Leandro S Palácio

Elisabete Teruel

Dr Ao Prof

Celso V Santilli

Dr Karim Dahmouche

Silvania Drª

Dr Michel Lanfredi

Wong

Dr Sandra H Pulcinelli E Ao

Peter Hammer

Rosembergue, Álvaro, Rodolfo Rodrigo Paula

Aline Fernanda

Lídia

Thiago, Nalva, Danúbia Marina Douglas

Marlon Bianca

Eloísa, Wellington, Yane, Celso, Fábio Ana Bruno

Samara

Andressa

Jorge Mayte

Ayoub

Mai Jérémy

Rafa Aos

Keywords: orgânico-inorgânicos, processo sol-gel, fotoluminescência, revestimentos OIH, condutores Hybrides organique-inorganique, procédé sol-gel, photoluminescence, revêtements OIH, conducteurs ioniques solides Organic-inorganic hybrids, Sol-gel process, Photoluminescence, OIH coatings, Solid ionic conductor

Neste trabalho de Tese uma metodologia sol-gel mais verde para a preparação de materiais híbridos orgânicoinorgânicos (OIH) a base de dois poli-éter amina terminal (Jeffamine®), o óxido de poli-etileno (PEO) e o óxido de poli-propileno (PPO), ligados de forma covalente com o agente reticulador ureasil (U) é apresentada. Devido aos diferentes sítios ativos presentes na estrutura do material OIH, uma vasta gama de cátions metálicos pode ser introduzida na matriz híbrida a partir da coordenação com os átomos de oxigênio do tipo éter ou do tipo carbonil. Assim, diferentes matrizes híbridas contendo cátions Eu 3+ e Li + , foram sintetizadas visando avaliar seu potencial como material fotoluminescente ou condutor iônico, respectivamente. O entendimento das características térmicas e estruturais dos OIH contendo cátions Eu 3+ ou Li + , assim como o efeito plastificante do PPO 2000 na blenda híbrida Ux PEO 1900 :/U-1-x PPO 2000 , (fração de PPO 2000 na mistura, x = 0,2, 0,5 e 0,8), foram investigadas por DSC e SAXS. Os resultados de DSC revelaram uma única temperatura de transição vítrea (T g ) para todos os materiais estudados. A adição de cátions Eu 3+ nas matrizes não causou variações nos valores de T g enquanto a adição de cátions Li + causou aumento dos valores de T g , indicando a existência de interações entre o cátion Li + e a fase polimérica do material OIH. As curvas calorimétricas referentes ao U-PEO 1900 ainda revelaram a presença de um pico endotérmico em 25 °C, associado à fusão dos domínios cristalinos do PEO 1900 . A presença de um segundo máximo nas curvas de espalhamento de raios X a baixo ângulo (SAXS) confirmaram a presença da estrutura semicristalina do PEO 1900 em uma região de temperatura entre -100 ºC < T < T f . Todas as amostras, não dopadas e dopadas com cátions Li + e Eu 3+ , apresentaram um pico de correlação, indicando que a nanoestrutura da matriz híbrida não é afetada pela dopagem com os cátions metálicos. As análises por Espectroscopia no Infravermelho com Transformada de Fourier (FTIR) e por Espectroscopia Raman confirmaram a interação dos cátions Eu 3+ com o oxigênio tipo carbonil, presente nos grupos ureia da matriz híbrida, e dos cátions Li + com o oxigênio tipo éter. A fotodegradação acelerada revelou uma perda da eficiência da fotoluminescência (PL) associada a mudanças na coordenação dos cátions Eu 3+ com a matriz híbrida. A fotodegradação induz a formação de fotoprodutos provenientes da β-cisão do macroradical formado na fração orgânica da matriz híbrida. A β-cisão pode ser a responsável da diminuição da PL do material devido a queda da eficiência do efeito antena do ligante orgânico para o centro luminescente. A transição no visível da cor de emissão de vermelho → azul com a fotodegradação qualifica estes materiais como bons candidatos para aplicação como sensores e marcadores ópticos. A condução iônica das matrizes híbridas dopadas com cátions Li + foi investigada por Espectroscopia de Impedância em função da temperatura e os resultados revelaram correlações entre a superestrutura lamelar do PEO 1900 com o processo de condução. A adição de um plastificante (PPO 2000 ) permitiu aumentar a condutividade iônica em regiões de baixa temperatura, -100 ºC < T < 10 ºC devido ao aumento da fração da região amorfa utilizada como caminho efetivo de transporte iônico na blenda híbrida polimérica Ux PEO 1900 /U-1-x PPO 2000 .

Palavras-chaves: híbridos

2.5 Schematic representation of a DSC pattern of a generic semi-crystalline polymer, representing the glass transition (T g ) and the melting point (T m ).

2.6 Microlithographic trends in minimum device feature size and imaging technology. The figure illustrates the time evolution of random access memory (RAM) devices. Meaning of acronyms at Glossary 2.7 Examples of the future manufacturing of electronic devices utilizing OIH materials.

2.8 Chemical formula of monomers constituting PEO and PPO polymers.

2.9 (a) Ionic transport interrupted by the active charger transfer saturation and (b) Dependency of the ionic conductivity with the charge transfer (n) concentration.

2.10 Schematization of the Li + ionic transfer mechanism (a) in the glass state (T < T g ) and (b) in the rubbery state (T > T g ).

2.11

Examples of natural light emitted by glow worms, Aurora Borealis, rotting fish and luminescent wood.

2.12 Luminescence spectrum [Eu(tta)3(phen)] at 77 K upon excitation at 396 nm. All of the transitions start from the 5 D 0 state 2.13 Schematic representation of the Eu 3+ :OIH complex derived from functionalized dipicolinic acid ligands. 3.8 Subtraction of the typical SAXS curve of the U-PEO 1900 OIH matrix by the power law contribution straight line curve. The insert show a schematic representation of the siloxane nodes distance spaced by the polymeric chain. xvii 6.20 Straight line equation SAXS curves subtraction at siloxane correlation peak (q max ) as a function of the temperature for Ux PPO 2000 :U-1-x PEO 1900 OIH blends for a x PPO 2000 content equal to (a) 0.8 -unloaded, (b) 0.8 -Li + -loaded, (c) 0.5unloaded, (d) 0.5 -Li + -loaded, (e) 0.2 -unloaded and (f) 0.2 -Li + -loaded.

6.21 (a) Evolution of the three different component areas (x10 -4 nm 2 ) and the middle-q area (nm [START_REF] Karimi | A click-derived dual organic-inorganic hybrid optical sensor based on SBA-15 for selective recognition of Zn 2+ and CNin water[END_REF] ) and (b) evolution of the average distance (ξ) relative to the three different components from the Gaussian fitting of the correlation peak for U-0.5 PPO 2000 /U-0.5 PEO 1900 OIH blend. 6.22 (a) Evolution of the three different component areas (x10 -4 nm 2 ) and the middle-q area (nm [START_REF] Karimi | A click-derived dual organic-inorganic hybrid optical sensor based on SBA-15 for selective recognition of Zn 2+ and CNin water[END_REF] ) and (b) evolution of the average distance (ξ) relative to the three different components from the Gaussian fitting of the correlation peak for U-0.2 PPO 2000 /U-0.8 PEO 1900 OIH blend.

6.23 Nyquist Impedance diagrams of the U-PEO 1900 :Li + monolith at various temperatures.

6.24 Nyquist Impedance diagrams of the U-0.2 PPO 2000 :Li + :U-0.8 PEO 1900 :Li + monolith at various temperatures.

6.25 Nyquist Impedance diagrams of the U-0.5 PPO 2000 :Li + :U-0.5 PEO 1900 :Li + monolith at various temperatures. Intensity of the scattered beam as function of the module of the scatter vector ICR:

Inter-configurational rearrangement IET:

Internal energy transfer IsoTREOs:

3-(isocyanate propyl)-trietoxisilane LIB:

Lithium-ion battery LIE:

Lanthanide ion emission Ln 3+ : lanthanide trivalent ion LSI: large scale integration K: Kelvin (temperature) K:

Geometric factor RAM:

Randon Access Memory MSI: medium scale integration OIH materials:

Organic-Inorganic Hybrid materials PEO:

Poly(ethylene oxide) PPO:

Poly(propylene oxide) PL: Photoluminescence SAXS:

Small Angle X-Ray Scattering SSI:

small scale integration T g : Organic-inorganic hybrid (OIH) materials have tremendous potential as a bridge between the organic, mineral, and biological universes, opening new frontiers for the development of systems and devices for industrial and technological applications. These OIH materials are not simply the sum of two components, but rather, a synergic combination. In fact, the applications of OIH materials penetrate nearly all of the scientific field, for example, environment, human health care, optics, electronics, membranes, protective coatings, catalysts, sensors, barriers, and biology [START_REF] Karthik | A visible-light active catechol-metal oxide carbonaceous polymeric material for enhanced photocatalytic activity[END_REF][START_REF] Karimi | A click-derived dual organic-inorganic hybrid optical sensor based on SBA-15 for selective recognition of Zn 2+ and CNin water[END_REF]3,4,5,6,[START_REF] Kwon | Two-terminal DSSC/silicon tandem solar cells exceeding 18% efficiency[END_REF][START_REF] Chen | Cross-cascaded AWG-based wavelength selective switching integrated module using polymer optical waveguide circuits[END_REF][START_REF] Croissant | Organosilica hybrid nanomaterials with a high organic content: syntheses and applications of silsesquioxanes[END_REF][START_REF] Catauro | Modification of Ti 6 Al 4 V implant surfaces by biocompatible TiO 2 /PCL hybrid layers prepared via sol-gel dip coating: Structural characterization, mechanical and corrosion behavior[END_REF][START_REF] Yao | Small organic molecule templating synthesis of organic-inorganic hybrid materials: their nanostructures and properties[END_REF] .

The multifunctional OIH materials developed in this thesis are nanocomposites based on an Ureasiloxane (ureasil -U) backbone covalently connected with polyether (PE) chains of either poly(ethylene oxide) (PEO) or polypropylene oxide (PPO). Due to the different polar sites present in the OIH structure, it is possible to have a wide variety of metal cations.

The repeating units grafted onto a siliceous backbone by urea, -NHC(=O)NH-, offers this material a blue emission under ultraviolet (UV) light. Their blue-emission can be tuned by adding cations with luminescent properties. In this way, the new emission color will be characteristic of the cation added into the OIH matrix. The organic templates play a key role, which mainly determines the morphologies, structures and properties of the hybrid materials, allowing them to be modified in different ways. Additionally, organic materials show poor mechanical stability, while inorganic materials show high resistance. In view of that, OIH materials have an enormous potential as protective coatings due the combination of the organic shape modification and the inorganic chemical/thermal/mechanical stability.

Dahmouche, K. et al [START_REF] Dahmouche | Structural modelling of Eu 3+ -based siloxane-poly(oxyethylene) nanohybrids[END_REF] , have studied the dependence of the Eu 3+ concentration with the oxyethylene repeat units by different spectroscopically techniques and have shown that in di-ureasils containing long organic segments, and low concentration of Eu 3+ , the ions interact mainly with the carbonyl-type oxygens of the urea cross-links located at the organic/inorganic interface. In contrast, in the di-ureasils with short organic segments at the same ratio of Eu 3+ concentration, the ions are unable to disrupt the strong and ordered hydrogen-bonded urea-urea structures and the preferential coordination sites are the ether-type oxygens of the polymer chains. However, for high salt concentration, the coordination of the Eu 3+ cations with the OIH matrices has a distinct cation local site environment, involving the interaction with the urea carbonyl oxygens atoms.

Ribeiro S. J. L. et al [START_REF] Ribeiro | Study of hybrid silica-polyethyleneglycol xerogels by Eu 3+ luminescence spectroscopy[END_REF] , have studied the photo-luminescence of OIH materials doped with different Eu 3+ concentrations and have demonstrated that for lower doping concentrations dried gels present statistical distributions of Eu 3+ , typical of an amorphous environment, while for higher concentrations a crystalline-like environment of Eu 3+ was observed. This behavior leads to a decreasing radiative decay rates and spectral variations suggest the transformation of Eu 3+ surroundings from amorphouslike to crystalline-like. The effect of the Eu 3+ concentration on the photo-luminescence of OIH materials was also studied by Bermudez, V. de Z. et al, and the authors have found similar results [START_REF] Bermudez | Coordination of Eu 3+ ions in siliceous nanohybrids containing short polyether chains and bridging urea crosslinks[END_REF] .

Molina, C. et al [START_REF] Molina | Enhanced emission from Eu(III) b-diketone complex combined with ether-type oxygen atoms of di-ureasil organic-inorganic hybrids[END_REF] , have studied the nano-structure of OIH materials with different Eu 3+ concentrations by EXAFS measurements which indicate a decrease in Eu 3+ coordination number with the increase in Eu-doping. A higher symmetry around the metal ion was also observed by increasing Eu 3+ concentration, while a non-radiative decay path from the 5 D 0 excited state become more important

Still talking about the reports done by Dahmouche, K. et al [START_REF] Dahmouche | Structural modelling of Eu 3+ -based siloxane-poly(oxyethylene) nanohybrids[END_REF] the authors have related for OIH materials based on poly(oxyethylene) chains, the possibility to tune the Eu 3+ coordination between the carbonyl oxygens of the urea groups and the ether oxygen atoms of the poly(oxyethylene) chains controlling both the salt concentration and the polymer molecular weight. For these reasons, looking for an Eu 3+ coordination with the urea group from the OIH materials, developed in this PhD thesis, with an amorphous surroundings for the guest cation, was adopted a low concentration of Eu 3+ , and the relationship, [O carbonyl ] / [Eu 3+ ] = 3 was kept constant for all materials studied.

Another field of application for OIH materials is in rechargeable lithium-ion batteries (LIBs). The emerging interest in materials with electrical properties comes from the increasing demand for electric vehicles, portable electronics, and implantable medical devices, due to their high energy density, high operating voltage, low selfdischarge, long cycle-life and low toxicity. The research and development of new series of polymer electrolytes for LIBs has remained popular for decades because of their better performance in safety and fabrication compared to liquid electrolytes, which could cause safety concerns due to leakage and the explosive nature of volatile organic electrolytes, especially at high temperatures (T > 60 °C). Solid OIH electrolytes were considered to be the most promising candidates for high-temperature LIBs by virtue of enhanced safety and dimensional stability.

In the study of Li + -loading OIH materials, prepared with different kinds of polyethers macromeres have been investigated, polymeric matrices used for ionslithium battery application, due to their high values of ionic conductivity [START_REF] Li | Novel Nanocomposite of Poly(acrylonitrile-co-glycidyl methacrylate) Crosslinked with Jeffamine-Functionalized Multiwalled Carbon Nanotubes as Gel Polymer Electrolytes[END_REF][START_REF] Ran | A polymer electrolyte based on poly(vinylidenefluoridehexafluoropylene)/hydroxypropyl methyl celulose blending for lithium-ion battery[END_REF][START_REF] Luo | Preparation and characterization of novel crosslinked poly[glycidyl methacrylate-poly(ethylene glycol) methylether methacrylate] as gel polymer electrolytes[END_REF][START_REF] Luo | Crosslinked poly(acrylonitrile-glycidyl methacrylate) as a novel gel polymer electrolyte[END_REF] . Some examples of polymers and their respective values of ionic conductivity are found in However, these polymer still exhibit low value of ionic conductivity for industrial application, which it is necessary the research for new kinds of materials with best electrical properties. Among them the poly(ethylene oxide) (PEO) has tremendous potential to this kind of application due to the ionic transport facilitate by the segmental motion of chain. However, the linearity polyether chain favors the crystallization and the formation of semi-crystalline structure, which makes difficult the ionic motion [START_REF] Luo | Preparation and characterization of novel crosslinked poly[glycidyl methacrylate-poly(ethylene glycol) methylether methacrylate] as gel polymer electrolytes[END_REF] . On the other hand, the development of OIH materials allows the fabrication of materials based on PEO with a lower degree of crystallinity, owing amorphous pathway to the ionic motion.

Dahmouche, K. et al [START_REF] Dahmouche | Investigation of new ion-conducting ormolytes silicapolypropyleneglycol[END_REF][START_REF] Dahmouche | New Li + ion-conducting ormolytes[END_REF] , have evidenced by room temperature AC Impedance Spectroscopy measurements with a maxima in the ionic conductivity for the relationship The third chapter will be focused on the study of the LIB, which will be analyzed to find the effect of Li This general objective is accompanied by the study of the effect of lanthanide and alkaline cation incorporation, photo-oxidation, temperature and the properties of PEO/PPO blending in their structure.

Specific objectives:

The specific objectives were classified into two sets, based on the functional properties of materials derived from the Eu 3+ or Li + salts incorporation.

 1.3.1 Europium salt;

The first set of objectives comprises of the expansion of the previous knowledge of lanthanide-containing materials and reports the influence of the polymer conformation from the ligand to metal charge transfer with reference to a detailed investigation of their crystalline-amorphous structures and vibrational properties. This set of objectives was achieved from an in-depth study of the OIH matrix structures, focused on the effect of the Eu 3+ -loading on the thermal, vibrational, structural and nanostructural properties.

Moreover, the optical properties were studied as a function of the artificial polymer photo-oxidation using photoluminescence and FTIR techniques to utilize Eu 3+ cations to probe its local environment, with special emphases on the loss of the "antenna effect" from the organic ligands and the Eu 3+ f-f transition. Thus, the specific objectives are:  Photoluminescence analyses of the OIH:Eu 3+ complex and its dependence on the UV-vis photo-degradation time:


o Photoluminescence  Correlate the evolution of optical and the structural properties during artificial aging.

 1.3.2 Lithium salt;

The second set of objectives aims to assess the effect of Ux PEO 1900 /U- The oldest reference of the existence of hybrids is found in Greek mythology 23 , (Υβρίδιο [hybris]) where fantastic creatures populate the human imagination. As an example consider the Griffon (Fig. 2.1), a creature that combines the strength of a lion with the shrewdness and flying ability of an eagle, thus resulting in a fearful guardian of the temple of Gods. Keeping this idea in mind, Organic-Inorganic Hybrid (OIH) materials possesses a tremendous interest in commercial applications due to their excellent physical-chemical properties which combine the thermal/chemical stability of ceramics with the workability and flexibility of organic polymers. The ability to conjugate the two (organic and inorganic) worlds into a unique material can lead to the development of a new series of multifunctional materials possessing inedited properties and a wide field of applications, such as: optics [START_REF] Kim | Enhancing light-extraction efficiency of OLEDs with high-and low-refractive-index organic-inorganic hybrid materials[END_REF] , energy [START_REF] Kashif | Cobalt polypyridyl complexes as transparent solution-processable solid-state charge transport materias[END_REF] , engineering 27 , environmental [START_REF] Pan | Fabrication of highly hydrophobic organic-inorganic hybrid magnetic polysulfone microcapsules: a lab-scale feasibility study for removal of oil and organic dyes from environmental aqueous samples[END_REF] , biology 29 , medicine [START_REF] Jin | Lanthanide-integrated supramolecular polymeric nanoassembly with multiple regulation characteristics for multidrug-resistant cancer therapy[END_REF] , solar cells 31 ,catalysis [START_REF] Fei | Syntheses, structures and catalytic properties of organic-inorganic hybrid materials constructed from Evans-Showell-type polyoxometalates and zinc-organic coordination units[END_REF] , sensors [START_REF] Zhao | Preparation of hydrophilic organic groups modified mesoporous silica materials and their humidity sensitive properties[END_REF] and batteries [START_REF] Kitschke | Porous Ge@C materials via twin polymerization of germanium(II) salicyl alcoholates for Li-ion batteries[END_REF] .

OIH materials are nanocomposites with the phase distribution on a nanometric scale [START_REF] Chaker | Correlações entre estrutura e propriedades de condução iônica em materiais híbridos siloxanopoli(propileno óxido), dopados com sais de sódio e potássio[END_REF] . The nature of the organic-inorganic interphases is used to categorise the OIH matrix into two classes. In class I, the interphase interaction is defined by weak bonds (hydrogen bonding, van der Waals, etc), while in class II the interphase interaction is characterized by the covalent bond between the inorganic and organic components [START_REF] Samento | Estrutura e propriedades de materiais híbridos siloxano-PMMA preparados pelo processo sol-gel. 2005. 168 f. Tese[END_REF] 

Hybrid Siloxane-Poly(ether);

Poly-siloxanes were synthetized for the first time by Hall, P. G. [START_REF] Hall | Ion conductivity in polysiloxane comb polymers with ethylene glycol[END_REF] and Fish, D. [START_REF] Fish | Conductivity of solid complexes of lithium perchlorate with poly{[-methoxyhexa(oxyethylene)ethoxy]methylsiloxane}[END_REF] , followed by the investigation of similar systems by Spindler, R. and Shriver, D. F. The chemical formula of poly-siloxanes is (R 2 SiO) n , where R is typically methylsiloxanes (CH 3 ), but can also be H, alkyl, or aryl groups. The siloxane-poly(ether) hybrid materials consist of a biphasic system in which the siloxane part acts as crosslinking nodes for the polymeric chain, thus giving rise to a three-dimensional (3D) network.

The The siloxane nodes present in the structure confer to the amorphous OIH materials an electron density contrast easily observed by Small Angle X-Ray Scattering (SAXS).

In the case of concentrated system the interference caused by the X-ray scattering from neighboring siloxane nodes led to a maximum at the q max value. However, the intensity can vary with the presence of guest cations, coordinated with the different polar oxygens present in the segment chain [START_REF] Molina | Fine-tuning of a nanostructure, swelling, and drug delivery profile by blending ureasil-PEO and ureasil-PPO hybrids[END_REF] and with the polymer backbone conformation, as with the PEO case [START_REF] Moura | Influence of the hydrophilic/hydrophobic nature of polyetheramines on the interaction between amine-alcohol-silicate hybrids and anionic dyes for effective water cleaning[END_REF] .

The linearity of PEO segmental chains confers to this polymer a helical conformation forming a semi-crystalline polymer [START_REF] Godovsky | Effect of molecular weight on the crystallization and morphology of poly(ethylene oxide) fractions[END_REF] . The presence of this crystallinity in the OIH matrix affects the correlation peak by the q max intensity decreases due to a lower electron density contrast between the organic-inorganic phases. Another interesting feature observed in semi-crystalline polymers is the presence of a second maximum located at middle q-range values which can be attributed to the long period peak. As displayed in Figure 2.3, the long period distance L is composed by the sum of the crystalline lamellae thickness LC and of the amorphous layer LA (L = LC + LA).

This reflection shows a temperature dependency and a persistency above the fusion temperature, which is not well known in literature and will later be discussed in chapter 4.

Relationship between Structure/Properties:

The multifunctional OIH matrices developed in this thesis have an intrinsic relationship between their different properties and their structure. The properties associated with ionic conductivity are intimately connected with their thermal behavior [START_REF] Mark | Hybrid Organic-Inorganic Composites[END_REF] . In the same way, the presence of the urea group in the OIH structure demonstrates an interesting photo-luminescent property, which shows a dependence on the polymeric nature [START_REF] Carlos | Full-color phosphors from amine-functionalized crosslinked hybrids lacking metal activator ions[END_REF] . The understanding of these properties will be explained in more detail below, which will be helpful for a better comprehension of the interpretation of the results discussed in Chapter 6.

Thermal properties:

The structure of polymers has an interesting dependence on the temperature. To gain a better understanding of this kind of material, knowledge about the concept of glass transition temperature, T g , is important. One first definition concerning T g values is the division of materials into two main families: Elastomers, when materials have a T g < 0 °C, and rigid structures, when polymers have a T g > 25°C.

Additionally, in terms of structure, these non-crystalline materials have different states: i) glass state, when T < T g , ii) rubber-like state, when T > T g . The representation of the volume variation of a non-crystalline material with the temperature is seen in Fig.

(curve 2

). From this Figure, it is observed that in a temperature range below T c that approaches the rubber-like state, the specific volume of the non-crystalline material decreases at almost the same rate that is found in the liquid-like state. The slope of the curves is drastically affected when the temperature reaches the T g of the non-crystalline material, where the volume variation becomes close to 0.

On the other hand, for a crystalline material Fig. 2.4 (curve 1), the cooling of the material in the liquid state shows a large change in of volume, characterizing the crystallization process, in a constant temperature. After that, in a semi-crystalline polymer will be found the mixture of these two effects in the same material [START_REF] Lee | Polymer Materials: block-copolymers, nanocomposites, organic/inorganic hybrids, polymethylenes[END_REF] . The glass transition temperature dependence for non-crystalline materials, for which the cooling rate is influenced by the relaxation time, is characterized by the time during which the structure adapts itself to a variation in temperature [START_REF] Klempner | Interpenetration polymer networks[END_REF] . At T > T g , polymer chains are capable of achieving equilibrium configurations, consequently, extra hole of "free volume" (υ f ), is created, thus giving rise to the noncrystalline, rubbery state. The presumption that molecular transport is regulated by free volume was first introduced by Cohen and Turnbull (1959). However, their conceptualization was initially believed to be suitable only for liquids. The "free volume" theory for ion diffusion through a polymeric system can be applied on several levels, and can also provide a basis for a qualitative understanding of the influence on diffusional behavior by variables such as temperature, concentration, and solvent molecular size. Elastomers, or non-crystalline rubber-like materials, in conditions far above their respective T g , possess a large fractional hole of "free volume". In this sense, the ionic motion through the segmental chains is not only large in magnitude, but also dependent on the temperature [START_REF] Duda | Free-volume theory[END_REF] . The dependence of υ f with T g is expressed as follows [START_REF] Cameron | Ionic conductivity in liquid polymeric electrolytes[END_REF] :

𝜐 𝑓 = 𝜐 𝑔 [𝑘 + 𝛼(𝑇 -𝑇 𝑔 )] (1)
As non-crystalline, amorphous materials are cooled, the motion of individual polymer chains becomes so constrained that the cooling rate becomes faster than the rate at which the polymer sample can volumetrically relax. The non-equilibrium condition created is referred to as the glass state. In this way, the glass state is a consequence of the free volume decrease, accompanied by a higher compaction of the organic chain segments [START_REF] Maccallum | Polymer electrolyte reviews[END_REF] . This leads to lower organic chain permeability, which results in decreased dissolution properties. Thus, the passage from the rubbery to the glass state is denoted as the glass transition. In this sense, the glass state can be defined as a system possessing solid mechanical properties while also exhibiting the typical structural features of a disordered liquid.

Quantitative information about the temperature at which the T g occurs in any material can be measured by the change in the ΔC p slope curves carried out by Differential Scanning Calorimetry (DSC) measurements (Fig. 2.5). This measurement is based on the classical thermodynamics shown by the Ehrenfest second-order transition, expressed as follows [START_REF] Cangialosi | Dynamics and thermodynamics of polymer glasses[END_REF] :

Π = 1 𝑉𝑇 Δ𝐶 𝑝 Δ𝑘 (Δ𝛼) 2
(2)

One of the basic characteristics of the glass transition is the Prigogine-Defay ratio Π, which is known to give a general correlation between the compressibility Δk, the thermal expansion coefficient Δα, and the isobaric heat capacity C p , while occurring in a temperature range near of the glass transition temperature T=T g [START_REF] Schmelzer | The Prigogine-Defay ratio revisited[END_REF] .

DSC measurements also provide other important information concerning semicrystalline polymers. At a temperature range above T g these materials are not completely amorphous, having a crystalline-amorphous phase equilibrium. The completely amorphous (liquid-like) phase is reached at the melting point (T m ), characterized as an endothermic peak. The peak area can be used to calculate the crystalline mass fraction. Miscible blends constituted by two or more non-crystalline polymers interact with each other, thus giving rise to a unique phenomenon of T g 41 . On the other hand, in the case of blended systems constituted by immiscible non-crystalline polymers, DSC patterns are identified by the presence of more than one glass transition temperature having a clearly defined separation between the two phenomena [START_REF] Fang | Location of a nanoclay at the interface in an immiscible poly(εcaprolactone)/ poly(ethylene oxide) blend and its effect on the compatibility of the components[END_REF] . The immiscible blend properties are controlled by their morphology, which is dependent on the thermodynamic properties, rheological properties and thermal history properties 56 .

Ionic Conductivity Properties:

As a consequence of the thermal properties, polymers show another important feature intimately correlated with the in temperature, ionic conductivity. The ionic conductivity is dependent on the polymer chain motion, which becomes more rigid and less conductive as the value of T g increases. The dependency of the ionic conductivity with T g is correlated using the Vogel-Tamman-Fulcher -VTF equation, derived from the Arrhenius-law, as follows [START_REF] Kuo | Influence of lithium salt addition on ionic conductivity and transporting properties of lithium bis(trifluoromethanesulfonyl)imide-doped glycine-based ionic liquid electrolyte[END_REF][START_REF] Philipp | Structure-property relationship and transport properties of structurally related silyl carbonate electrolytes[END_REF] .

𝜎 = 𝜎 0 𝑒𝑥𝑝 ( -𝐸𝑎 𝑇 -𝑇 0 ) (3)
where σ 0 , T 0 and Ea are fitting parameters. σ 0 is the well-known Arrhenius preexponential factor, which represents the frequency of collisions. For polymers, σ 0 can be associated ith the organic chain mobility as well as the state density. T 0 is supposed to have a close relationship with the glass transition temperature, and Ea is the activation energy 59 .



Ionic conductors;

The term "molecular electronics" had a strong impact on the scientific community in the 1990s because the idea that a single molecule might function as a self-contained electronic device gave rise to the possibility of developing a computer based on molecular-sized electronic elements [START_REF] Bowden | Polymers for electronic and photonic applications[END_REF] . After the first studies conducted by Wright P.

V. [START_REF] Wright | Cyclization equilibrium constants and the conformations of polydimethylsiloxane chains[END_REF] in 1973 in the field of ionic conductivity of a material based on Poly(ethylene oxide) (PEO), the evolution of electrolytic, solid polymers have shown a wide expansion [START_REF] Armond | Estudo de eletrólitos poliméricos a base de poliéter por espectroscopia raman, análise térmica e condutividade iônica[END_REF] , reflecting the progress of the understanding of the ionic motion process and the correlation between the molecular architecture, supramolecular and conductivity.

The possibility of utilizing "molecular electronics" was first discussed by Carter, F.

L. in 1981 [START_REF] Carter | Molecular electronic devices[END_REF] and 1983 [START_REF] Carter | Molecular electronic devices II[END_REF] , which led to a progression in the semiconductor industry, with the size reduction of electronic devices on the order of micrometers (μm). Extrapolation of information from a timeline composed of research from this time (Fig 2.6) show that within about 30 years, electronic components will reach a size on the order of nanometers. A set of polymeric materials shows an ionic conductivity value around 10 -7 and 10 -6 S.cm -1 at room temperature, even after lithium salt dissociates into the matrix. However, this range of conductivity is far below those considered attractive for Lithium-ion

CH 2 CH 2 O CH 2 CH 2 O n CHCH 2 O CHCH 2 O n CHCH CH 3
PEO PPO battery (LIB) applications (10 -3 -10 -2 process. They have found that the plasticized hybrid electrolytic membrane exhibits a high ionic conductivity, with a value of 6.9x10 -3 S.cm -1 at 30 °C.

Poly(ethylene oxide) -PEO 1900 , i.e.: wt = 1900 g.mol -1 , is a semi-crystalline polymer, possessing both amorphous and crystalline phases at room temperature, thus being an excellent candidate to apply as LIBs due to its capability of ionic transport that is facilitated through the polar -oxygens present in the segment of the organic chain, which allows for the dissolution of a wide variety of inorganic cations. Li + ions dissolved in poly-ether-based OIH, have several advantages, such as good compatibility, ease of shaping into thin films of large surface area, leak-proof nature, and manufacturability [START_REF] Schantz | On the ion association at low salt concentrations in polymer electrolytes; a Raman study of NaCF 3 SO 3 and LiClO 4 dissolved in polypropylene oxide[END_REF][START_REF] Anilkumara | Poly(ethylene oxide) (PEO) -poly(vinyl pyrrolidone) (PVP) blend polymer based solid electrolyte membranes for developing solid state magnesium ion cells[END_REF][START_REF] Soo | Rubbery block copolymer electrolytes for solid-state rechargeable lithium batteries[END_REF][START_REF] Ruzette | Melt-formable block copolymer electrolytes for lithium rechargeable batteries[END_REF] . On the other hand, the multiphase nature of semicrystalline PEO is most often regarded as a major problem in this kind of materialdue to the transport of Li + ions in these electrolytes, which is associated with the local relaxation and segmental motion of the amorphous regions in the PEO chains [START_REF] Choi | Poly(ethylene oxide)-based polymer electrolyte incorporating roomtemperature ionic liquid for lithium batteries[END_REF] . The suppression of crystallinity of polymer chains improves the polymer chain mobility, which in turn, leads to better ionic transfer through the organic chain segments [START_REF] Kumar | Investigations on the effect of complexation of NaF salt with polymer blend (PEO/PVP) electrolytes on ionic conductivity and optical energy band gaps[END_REF] .



Lithium-ion battery;

Rechargeable lithium-ion batteries (LIBs) are emerging power sources that are currently used in many portable electronic devices and electric vehicles due to their high energy density, high operating voltage, low self-discharge, long cycle-life and low toxicity [START_REF] Aldalur | Jeffamine® based polymers as highly conductive polymer electrolytes and cathode binder materials for battery application[END_REF] .

However, new battery components must be developed for some applications in order to obtain high performance LIBs with better safety and low cost. incompatible with the high temperature range due to the volatility and flammability of the added plasticizer [START_REF] Chaurasia | mechanical, structural, and thermal behaviors of polymeric gel electrolyte membranes of poly(vinylidene fluoride-cohexafluoropropylene) with the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate plus lithium tetrafluoroborate[END_REF] . Because of this, the Siloxane-Poly(ether) OIH Li + -containing materials developed in this thesis deserve special attention for this kind of application, which combines their excellent mechanical / thermal properties with the possibility of allowing the organic portion to behave independent of the inorganic one [START_REF] Grünebaum | Synthesis and electrochemistry of polymer based electrolytes for lithium batteries[END_REF] .



Effect of the plasticizers in conductivity;

Polymeric blends often exhibit properties that are superior to the single-component polymers. A similar observation was made with enhanced ionic conductivity of PEO:Li + -loaded electrolytes with the addition of pyrrolidinium (RTIL), which was reported by Shin J. H. in 2005 [START_REF] Shin | PEO-based polymer electrolytes with ionic liquids and their use in lithium metal-polymer electrolyte batteries[END_REF] ; the effect was attributed to the formation of a saltcontaining amorphous phase of PEO at low temperatures with RTIL leading to an overall reduction of crystallinity of the system. Plasticizers are often utilized to improve material flexibility by lowering the glass transition temperature [START_REF] Nollenberger | Poly(meth)acrylate-based coatings[END_REF] . The Li + ions that are bonded with the "O" atoms of PEO segments could be partially or fully freed from that trap by bonding with the anion of RTIL, hence leading to a larger number of charge carriers with improved charge migration. Thus, incorporation of RTIL is an effective way of enhancing the ionic conductivity of PEO-based PEs to an appreciable level [START_REF] Shin | PEO-based polymer electrolytes with ionic liquids and their use in lithium metal-polymer electrolyte batteries[END_REF] .

As a result, several approaches have been developed in order to improve the ionic conductivity by increasing the OIH:Li + monoliths amorphous content, such as addition of nanosized particles, copolymerization, dispersion of different fillers, synthesis of block copolymers or blends and use of different plasticizers [START_REF] Deng | Microporous polymer electrolyte based on PVDF/PEO star polymer blends for lithium ion batteries[END_REF][START_REF] Nimah | Solid-state polymer nanocomposite electrolyte of TiO 2 /PEO/NaClO 4 for sodium ion batteries[END_REF][START_REF] Jung | Thermal behavior and ion conductivity of polyethylene oxide/polyhedral oligomeric silsesquioxane nanocomposite electrolytes[END_REF] . The high value of conductivity could also be attributed to the presence of plasticizers, which reduces the viscosity of the poly-electrolyte and assists in the metal salt dissociation, thus contributing to the increase in the number of charge carriers in the films [START_REF] Kumar | Investigations on PEO/PVP/NaBr complexed polymer blend electrolytes for electrochemical cell applications[END_REF] . The reduced viscosity improves the segmental motion of the host polymer, therefore increasing its backbone segmental flexibility 86 .

 2.4.4 Others parameters affecting the ionic conductivity;

Alternatively, the ionic conductivity is not only sensitive to the degree of crystallinity of the polymer matrix, but also to two other important factors:

i) The salt concentration -i.e.: the conductivity of an electrolyte is highly dependent on the charge carrier concentration, n, the nominal charge of the carriers, q, and the mobility of the charge carrier, μ, through the relation of σ = nqμ [START_REF] Verma | Ab initio study of mechanical strength of solid polymer electrolyte (PEO) 5 LiClO 4[END_REF] . Therefore, as the salt concentration increases, the number of the charge carriers will also increase, which then leads to the enhancement of the conductivity. However, a high value for the charge carrier concentration can saturate the polymeric active sites, thus decreasing the ionic motion [START_REF] Kumar | Ionic conduction in the solid state[END_REF] . Considering this for our work, we have decided to utilize a ratio well-known by the literature, [O ether ]/[Li + ] = 15 [START_REF] Dahmouche | Investigation of new Ion-Conducting Ormolytes: Structure and Properties[END_REF] . Fig. 2.9 shows the effect of a high charge carrier concentration on the ionic conductivity. ii) The temperature: the polymer segmental chain motion is highly dependent on the T g value of the polymer backbone. In a temperature range below T g , the rigidity is enough to block the ionic motion through the polymeric active sites, preventing ionic conductivity (Fig. Siloxane-polyether OIH materials have another interesting property, which is their photoluminescent capacity, emitting a blue light when exposed to UV-radiation. The characteristic blue color of these matrices comes from NH groups from urea bridges and the electron-hole recombination in the siliceous domains in the inorganic backbone, which leads to a broad emission. The photo-luminescent properties offer a new range of possible applications to Siloxane-polyether OIH materials developed in the thesis. This is true once their luminescent features can be tuned, adding most, or all, luminescent cations in the form of trivalent lanthanide ion (Ln 3+ ). For this kind of application, it is important to know that the luminescent properties of the OIH:Ln 3+ complex can happen independent of the ionic conductivity. This knowledge is important to open new fields of application for this material; as an example, it can be used as the OIH bio-marker material, which was developed by Powell J. A. and co-authors [START_REF] Powell | Hybridized enhancement of the SERS detection of chemical and bio-marker molecules through Au nanosphere ornamentation of hybrid amorphous/crystalline Si nanoweb nanostructure biochip devices[END_REF] , which is vital to the understanding of metal coordination/ discoordination, life time, bio-compatibility, among others.

 2.5.1 Luminescence;

Luminescence is a spontaneous radiative recombination process which involves the participation of electrons and holes. According to IUPAC, luminescence is defined as follows: "Spontaneous emission of radiation, from an electronically or vibrationally excited species not in thermal equilibrium with its environment" [START_REF]IUPAC compendium of chemical terminology -the Gold book[END_REF] . The excitation of carriers prior to recombination requires a potential driving energy, which can be electrical, optical, mechanical or thermal. Although several publications report its radiative emission as phosphorescence or fluorescence, it is recommended to nowadays use the term "Luminescence" for all these phenomena. There have been related studies of luminescent materials since the seventeenth century, which was the origin of the phosphor (phosphori) denomination on the study of BaS, believed to be the first-ever synthesized sulfide phosphor, realized by Vincenzo Casciarolo in 1602 [START_REF] Roda | The discovery of luminescence: the bolognian stone[END_REF] i.e.: The word phosphorus derives from the Greek ϕϖσϕορος[fosforos], combining φϖσ (light) and φερϖ (to carry), therefore meaning light carrying or luminous [START_REF] Yen | Inorganic phosphors: compositions, preparation and optical properties[END_REF] ; in 1888, Eilhard

Wiedemann introduced the terms luminescence, photoluminescence (PL), electroluminescence (EL), thermoluminescence (TL), chemiluminescence, triboluminescence, and crystalloluminescence by creating the first classification of different phosphors based on their type of excitation [START_REF] Wiedemann | Ueber Fluorescenz und Phosphorescenz I. Abhandlung[END_REF] .

This phenomenon has captivated mankind for a long time, whether it was through natural light emitted by glow worms, Aurora Borealis, rotting fish, or luminescent wood (Fig. 2.11). The utilization of the luminescence properties was documented by the Chinese people as early as 2000 years ago. It was used for paintings which glowed in the dark; the source of this effect belongs to the lanthanides family, more specifically, the trivalent lanthanides ions, Ln 3+ , whose luminescence occurs naturally [START_REF] Khare | Optical properties of rare earth doped srs phosphor: a Review[END_REF] . [START_REF] White | The glow worms adaptations[END_REF][START_REF]THE 10 BEST places to stare in awe at the aurora borealis[END_REF][START_REF]EXPLORE peixe de água salgada e muito mais! Pinterest[END_REF][START_REF] Workshop | Make a log slice wood art décor -woodworking[END_REF] ].

 2.5.2 Europium (III);

It is already known that organic ligands and ion concentrations have great influence on the luminescent properties of Eu 3+ due to the variation of the microenvironments around the cations 100 . On the other hand, there are several reasons why the Eu 3+ ion is so often used as a spectroscopic probe for the symmetry of the first coordination sphere of a trivalent lanthanide ion. First of all, Eu 3+ ions are excellent activators with strong redemission and high luminescence quantum efficiencies, good color purity and great radiation stability 101 . The ground state ( 7 F 0 ) and the most important emitting excited state ( 5 D 0 ) are non-degenerated and thus, are not split by the crystal-field effect. The most important transitions in the luminescence spectra are from the 5 D 0 excited state to [START_REF] Kwon | Two-terminal DSSC/silicon tandem solar cells exceeding 18% efficiency[END_REF] F J levels with a low J value (J = 0, 1, 2). This also facilitates the interpretation of the experimental absorption and luminescence spectra. Furthermore, the trivalent europium ion (Eu 3+ ), comparable to Ln 3+ 5 D 0 → 7 F J transition intensities, provides an asymmetrical ligand field that drastically facilitates the 5 D 0 → 7 F 2 transition to yield an essentially monochromic single-band red photoluminescence emission 102 . This characteristic allows for the use of Ln 3+ to probe its local environment 103 , which shows that the different 5 D 0 → 7 F J lines are well separated, meaning that there is virtually no overlap between the crystal-field levels belonging to different 7 F J levels. Another interesting characteristic is that the wave functions of the 7 F J levels and of the 5 D 0 , 5 D 1 and 5 D 2 excited states are well described within the intermediate coupling scheme and J is a good quantum number. J-mixing is limited so that there is very little flexibility with the selection rules and it is possible to obtain an accurate theoretical description of the energy level structure of the 4f 6 configuration of Eu 3+ 104 .



Luminescence mechanism of Ln 3+ ions and selection rules;

Ln 3+ ions have attracted considerable research interest due to their excellent luminescent properties, especially because they have intra 4f-4f luminescence spectra characterized by narrow lines with high color purity. This feature is observed due to the shielding of 4f electrons by outer 5s 2 and 5p 6 electrons 105 .

A luminescence spectrum (or emission spectrum) is recorded by fixing the excitation wavelength while the detection wavelength of the spectrofluorimeter is scanned. The luminescence spectra of Eu 3+ compounds are more informative than the corresponding absorption spectra. Many Eu 3+ compounds show an intense photoluminescence, due to the 5 D 0 → 7 F J transitions (J = 0-6) from the 5 D 0 excited state to the J levels of the ground term 7 F. However, 7 F 5 and 7 F 6 transitions levels are not often observed because they are outside of the wavelength range of the detectors, as represented at Fig. 2.12, which shows the luminescence spectrum of the europium βdiketonate complex[Eu(tta)3(phen)] / (tta = 2-thenoyltrifluoroacetylacetonate, phen = 1.10-phenanthroline). The Eu 3+ emission spectra, in the spectral range from 575 to 725 nm, reveals that the positions of the different 5 D 0 → 7 F J transitions between the J and the J + 1 line increases with an increasing J value, i.e.: the 5 D 0 → 7 F 1 transition is very close to the 5 D 0 → 7 F 0 transition, but the 5 D 0 → 7 F 4 transition lies more than 50 nm further from the infrared than the 5 D 0 → 7 F 3 transition 106 . Most transitions observed in the luminescence spectrum for Ln 3+ compounds are induced by electric dipole transitions (ED transitions), which are a consequence of lanthanide ion and electric field vector interactions through an electric dipole. not always completely fulfilled in real compounds, so in reality, the terms "forbidden"

and "allowed" transitions should be understood as "low probability" and "high probability" transitions 107 .

 2.5.4 Lanthanide containing OIH materials;

A search for lanthanide luminescence and related terms in any bibliographic database or web search engine will typically return tens of thousands of articles; even just within the last year, there were more than a thousand publications pointing to its popularity in several fields, such as in catalysis 108 , photovoltaics 109 , sensors for ethanol 110 , temperature 111 and pH 112 , solar cells 113 , bio-imaging 114 , markers 115 , etc. Their popularity came from an attractive feature of luminescent lanthanide compounds, their line-like emission, which results in a high color purity of the emitted light. The emission color depends on the lanthanide ion, but is mainly independent of the environment 116 .

Due to the shielding by the 5s 2 and 5p 6 electrons, the 4f electrons weakly interacts with the ligands with an electrostatic nature and the complex geometry is conditioned to steric factors. This phenomenon is accompanied by the high values of ionic radius, which favors the formation of Ln 3+ compounds with a high coordination number (CN), varying from 6 to 12, with CN numbers 7, 8 and 9 being the most common. This feature motivates the conjugation of Ln 3+ complex luminescence with nanoparticles 117,118 , polymer matrices 119,120,121 , glass-ceramics 122,123 , mesoporous/microporous materials 124 , ionogels 125,126 , inorganic hosts such as zeolites/silica 127,128,129 and metal-organic frameworks (MOFs) 130,131,132 .

Among the different variety of conjugations, the incorporation of Ln 3+ on organicinorganic hybrid (OIH) matrices 133,134,135,136,137 is the most interesting in terms of processing due to their possibility of tailoring not only the optical response, but also, controlled for specific applications, other properties such as mechanical and chemical resistance, thermal stability, hydrophobicity, and optical quality or refractive index, which must be controlled for specific applications 138 . In general, OIH materials have superior mechanical properties and have a better workability than lanthanide complexes incorporated into ceramic and glass materials.

Franville and coworkers, prepared Eu 3+ -containing OIH materials based on derivatives of pyridine-2,6-dicarboxylic acid (dipicolinic acid). The Eu 3+ ions were introduced in the sol as Eu(NO 3 ) 3 x6H 2 O, and the Eu 3+ /ligand ratio was 1/3 139,140 . A schematic representation of the OIH:Eu 3+ matrix complex is shown in Fig. 2.13. Moreover, the incorporation of lanthanide complex in hybrid matrix is also beneficial for its luminescent characteristics 133 . The most pronounced effect caused by Ln 3+ incorporation in silica matrices is the broadening of Ln 3+ emission peaks, while the relative intensities of the emission bands and the luminescence decay times were relatively unaffected 136 . The luminescence decay times were slightly lower in the hybrid materials than in the Ln 3+ organic complexes; this was attributed to the residual silanol groups in the OIH. The silanol groups do not directly interact with the Eu 3+ ion, but their presence in the second coordination sphere influences the luminescence properties, for instance, via hydrogen bonding with the chelating groups of the ligands 104 .



Antenna Effect;

The OIH materials developed in this thesis are composed of macromer grafted onto a siliceous backbone by urea, -NHC(=O)NH-, which offers a blue emission under ultraviolet (UV) light (Fig. 2.14 (a) -left). Their photoluminescence (PL) can be tuned by adding trivalent lanthanide (Ln 3+ ) cations. In this way, the new emission color is characteristic of the Ln 3+ added into the hybrid matrix, (Fig. 2.14 (a) -right), showing

O Si O O Si O O O Si O O H Si O Si O O O O Si O Si O O O O Eu 3+ Si O O Si O O O Eu 3+ Si O Si O O O O Si O Si O O O O O Si N O N N O Si Si O O N O N N O Si Si Eu 3+ N O N N O Si Si O O O Si O O O O O O O O H H H H H O Si O Si O O Si O O O Eu 3+ = N N N H H O O
that the OIH:Eu 3+ has a blue → red emission transition. A representation of the incorporation of different Ln 3+ in a generic OIH matrix is shown in Fig. 2.14 (b), where a to h indicates the luminescent properties resulting from the inclusion of different Ln 3+

guests into the matrix. It is well known that the PL of Ln 3+ shows a limited intensity due to the poor UVabsorption from the forbidden Laporte transition and from the intra-configurational nature of the 4f transitions 116 . The trivalent europium ion (Eu 3+ ) exhibits an intense red photoluminescence upon irradiation with UV light 100 . This PL is observed not only for Eu 3+ ions doped into crystalline host matrices or glasses, but also for Eu 3+ complexes with organic ligands 104 . Consequently, organic ligands with a high absorbing coefficient are usually utilized in Ln 3+ coordination, where the characteristic emission observed is the result of the organic ligand energy transfer to the Ln 3+ center 103 . This phenomenon, (a) (b) called the "antenna effect" 142,143 , represented in Fig. 2.15, was first reported by

Weissman 144 . The mechanism consists of UV-light absorption by the organic ligand coupled with an "Inter-configurational rearrangement" (ICR) from a singlet state to a triplet state, for example, followed by an "Internal Energy Transfer" (IET) of the light to the luminescent center, and a subsequent highly efficient "Lanthanide Ion Emission"

(LIE) [START_REF] Carlos | Full-color phosphors from amine-functionalized crosslinked hybrids lacking metal activator ions[END_REF] . However, the Eu 3+ 5 D 0 → 7 F 2 transition is very sensitive to the environment, showing to be more intense for a complex ion than for a fully hydrated ion in water; the intensity can be enhanced in some cases by a factor of 100 or even more 104 . Sinha, S. P. shown a total of four publications 151,152,153,154 for the keywords "hybrid materials" and "photoageing", revealing the real importance of focusing scientific attention on this investigation. However, there are not any photo-ageing studies concerning Siloxane-Poly(ether) OIH matrices.

Antenna Effect Antenna Effect

OIH materials demonstrate a great potential in engineering applications including coatings and films 155,156,157 based on polyesters, polyurethanes, epoxies, acrylicmelamine composites, among others. Depending on the application, these materials are subjected to several environmental ageing factors, including UV light, temperature and atmospheric oxygen. One of the most important properties that organic coatings must fulfill is weathering resistance. The property changes due to the ageing and external conditions and have to be monitored and quantified to determine the weatherability of materials and the PL stability when exposed to sun radiation. On the other hand, all polymers, without exception, are eventually degraded within the environment to which they are exposed during their life cycle. Degradation and oxidation of the polymers have several serious effects on its physical, chemical and mechanical properties, like mass transport, tensile strength, impact strength, creep, etc 158 . The most common processes leading to degradation are photo-initiated oxidation and hydrolysis, resulting from unavoidable exposure to light, air, temperature and/or water. The rate at which these processes occur varies widely, depending on the exposure site, time of year, coating composition and substrate. However, it is difficult to know the polymer's incident solar energy when exposed to natural weathering conditions due to the variability of the season, time and geography 159 . The most common procedure consists of using UV-light irradiation (λ > 300 nm), which is appropriate to simulate the solar UV-range due to the ability of these materials to absorb light within this wavelength range 160 .

Early detection methods are based on highly sensitive techniques for detecting the onset of degradation, which are ideally carried out on samples subjected to ambient weathering in the field. Some works have focused on investigations of the chemical mechanisms based on infrared (IR) spectroscopy data 161,162,163,164 , which is a useful tool for characterizing the degradation of the chemical structure and the understanding of the pathways of degradation.

The reactivity and the mechanism of degradation for OIH materials are directly related to their chemical structure. Polymeric materials photo-ageing at λ > 300 nm have been widely studied 165 and involve a mechanism of oxidation via radical, leaving hydroperoxides to form as primary products. The hydroperoxides formed decompose photochemically, thus giving formates, ketones, esters and hemiacetals, (which are thermally unstable and give rise to alcohols and carboxilyic acids, given that the degree of reaction propagation depends on the polymeric chain mobility 166,167 ).

Garlette, J-L. et al. studied amorphous polypropylene (PP) films after UVirradiation, combining IR analysis with chemical derivatization reactions and physical treatments, which allowed the authors to observe ketone and acids formation as the main photo-products after UV-light irradiation 168 . However, several basic aspects of the mechanism of oxidation remain unclear. We intend to combine PL and FTIR measurements to better understand this phenomenon by observing the emission of light by lanthanide discoordinated OIH materials with a special emphasis on the loss of the "antenna effect" from the organic ligands and the Eu 3+ f-f transition.

2.6 Sol-gel method:

OIH materials based on PEO and PPO polymers can be synthetized by the sol-gel process. This procedure allows for effective control of size and homogeneity in the matrix, enabling the covalent bonding between the inorganic-organic phases 169 . The solgel process has another advantage compared with other synthetic routes since it involves the use of mild conditions of temperature and pressure 170 .The sol-gel transition is a phenomenon in which a colloidal suspension becomes a gel by the bonding of nanoparticles, or oligomeric species, leading to the formation of 3D networks 171 . The chemistry of the sol-gel process is based on an inorganic polymerization reaction 170,172 and their chemical precursors are often salts or metal alkoxides. The sol-gel procedure can be divided into the following steps: i) Precursor hydrolysis ii) hydrolyzed precursor poly-condensation -sol formation and gelation, iii) aging and iv) drying 173 .

The hydrolysis and condensation reactions usually occur together in the initial synthesis steps, the reaction kinetics depend on the kind of precursors, temperature, reaction conditions, pH and ionic strength 173 . For alkoxide precursors, the reaction between the alkoxide M-OR and water can produce aquo or hydroxo (M-OH) complexes (Equation 4). The M-OH species are essential for the condensation reactions leading to the formation of M-O-M poly-condensates 174 . The global sol-gel reactions involving alkoxides of transition metals M(OR) x are expressed as follow 175 :

M(OR) x + H 2 O → M(OH)(OR) x-1 + ROH (4) M-OH + M-OH → M-O-M + H 2 O (5) M-OH + M-OR → M-O-M + ROH (6)
The hydrolysis procedure is strongly dependent on the pH solution, which determines the type of catalysis mechanism. The silicon alkoxide acid hydrolysis involves the protonation of an alkoxide group, followed by the nucleophilic attack of water to form a transition state (Fig. 2.16 (a)). The elevated hydrolysis rate promotes the growth of siliceous networks, thus leading to a polymeric solution. The ramified structure gel that is obtained is called "polymeric gel".

On the other hand, under basic catalysis conditions, the anion coming from the water dissociation reacts with the siliceous atoms by a nucleophilic attack, thus forming a penta-coordinate intermediate. In this case, the gel formed is called "colloidal gel" having a structure formed by agglomerates leading it to a ramified network (Fig. 2.16 (b)) 171 . At pH neutral conditions, it is expected that the hydrolysis and condensation occur by a nucleophilic addition followed by proton transfer and water and alcohol elimination

The kinetics for the hydrolysis and condensation of siliceous alkoxide is slow, allowing for the control of these reactions during the synthesis procedure from acid/basic catalysis. Due to this fact, both sol and gel can be used in the conformation of objects with different shapes, like thin films, monoliths, and others 182 . The step-by-step procedure of the sol-gel process for OIH materials (even the Li + /Eu 3+ -loaded) are explained in detail in Chapter 3 Si O The OIH precursor was synthesized according to the procedure already well-known by GFQM -UNESP 176 . In brief, the ureasil (U) cross-linking agent (3-(isocyanatopropyl) -triethoxysilane -IsoTrEOS) was covalently bonded to both ends of the functionalized PPO (O.O′-bis(2-aminopropyl)poly(propylene oxide)) by reacting their terminal aminopropyl groups in a molar ratio of 1:2. These commercially available reagents (Fluka, Aldrich) were stirred together in ethanolic solution under reflux for 6 h at 78 ºC, leading to the formation of the OIH precursor, (EtO) 3 Si-

R + H + + fast Si O + + R H Si O + + R H + HOH . . Si HOH Si O + R H O H H Si Si O + + R H O O O H H H H + Si O H + ROH + H + (a) Acid catalysis (b) Basic catalysis OH - . . H + + H 2 O Si O R OH - . . + - Si O R O H Si Si O O O R O O O H H - Si Si O O R O O H - Si Si O O R O O H - R - Si O R O H Si Si O O O R O O O H H Si HO + RO -
(CH 2 ) 3 NHC(=O)NHCHCH 3 CH 2 -(polyether)-CH 2 CH 3 CHNH(O=)NHC(CH 2 ) 3 -Si(OEt) 3 .
This procedure has shown to be an efficient method for the preparation of OIH matrices 177 in comparison to the oldest method that uses tetrahydrofuran (THF) as the solvent and 15 h of reflux. This procedure, proved to be a more green route, has shown to be adopted for U-PEO 1900 and U-PPO n with average molecular weight (mw) of 230, 2000 and 4000 g.mol -1 (labelled as U-PPO 230 , U-PPO 2000 and U-PPO 4000 ).

The second step involves the sol-gel reactions comprised in the hydrolysis of Si(OEt) 3 , generating silanol moieties ensued by the condensation reaction to form ureasil cross-linking nodes. Hydrolysis starts by adding a specific volume of water to satisfy the relationship: [𝐇 𝟐 𝐎] / [𝐒𝐢] = 𝟒, (Table 3.1), and 12 μl of HCl (10 -2 mol.l -1 ) employed as a catalyst in 1.6 mL of the ethanoic precursor solution (this volume is equivalent to 0.5 g of dry precursor). This procedure leads to the formation of a rubbery material with two different polar oxygen active sites, named as I and II (Fig 3 .1), ascribed to oxygen ether-type and carbonyl-type, respectively, which allow for a wide variety of guest cations for complexation. Li + / Eu 3+ -OIH complex formation was carried out by the solubilisation of a desired proportion of bis(trifluoromethane) sulfonimide lithium salt (Fluka, Aldrich, The measurements were performed in Soleil, Saint-Aubin -France. Data with a resolution of 2 cm -1 was collected, it ranged from 100 to 3100 cm -1 . Raman spectra were recorded every 12 seconds during heating from -85 °C to + 100 °C, at 5 °C/min, in order to collect one spectrum of each degree (°C).

Fourier Transform InfraRed (FTIR);

Infrared spectra were recorded with a Nicolet 760-FTIR spectrometer, working with OMNIC software. Spectra, in transmission mode for the OIH films (≈ 50 μm) were obtained using 32 scan summations and a 4 cm -1 resolution in a spectral range from 400 to 4000 cm -1 .

 3.3.5.1 Qualitative identification of species derived from OIH photo-aging:

The photo-oxidized samples were subjected to a NH 3(g) chemical treatment in order to identify their photoproducts. The irradiated films were exposed to reactive gas at room temperature in a simple flow system that could be sealed off to permit the reaction to proceed. In parallel to those treatments, ammoniac chemical treatment showed itself to be inert when Eu 3+ -unloaded because the hybrid matrices were not reacting with the gas (Fig. The evolution of the nanostructures of the hybrids was monitored by small angle Xray scattering (SAXS) recorded in in situ during controlled change of temperatures. The measurements were performed at the SAXS1 beamline of the National Synchrotron Light Laboratory (LNLS, Campinas, Brazil). The instrumentation was equipped with a multi-layer monochromator (λ = 1.550 Å), a 2D Pilatus 300k detector located 910.9 mm from the sample, and a multichannel analyzer to record the scattering intensity, I(q), as a function of the modulus of the scattering vector, q = 4π/λsin(ε/2), where ε is the X-ray scattering angle. The data was normalized by considering the varying intensity of the direct X-ray beam, detector sensitivity, and sample transmission.

I (q) q (nm -1 ) Experimental SAXS curve Straight line equations y = a + (b * x) + cte I(q calculate ) = a * (q nm -1 ^ b) + cte 0 1 2 3 4 5
low-q values q max q (nm -1

) I(q experimental ) -I(q theoric ) I(q experimental ) -I(q theoric ) Theoric fitting curve

 s = (2 * ) / q max 2 3 4 5  s = (2 * ) / q max  3.

Photo-Luminescence;

The external quantum efficiencies were estimated using the C9920-02G PL-QY measurement system from Hamamatsu. The setup comprised of a 150 W monochromatized Xe lamp, an integrating sphere (Spectralon® Coating, Ø = 3.3 inch) and a high sensitivity CCD camera for detecting the whole spectral luminescence (the emission spectra were integrated from 576 nm to 728 nm for the europium-based compounds). The automatically controlled excitation wavelength range spread from 250 nm to 500 nm with a resolution bandwidth better than 5 nm. Absolute photoluminescence (PL) quantum yield excitation spectra were recorded for PEO 1900 and different molecular weight U-PPO n , Eu 3+ -loaded OIH materials, in the solid form, and obtained by scanning the excitation and monitoring the overall luminescence of Eu 3+ .

The values reported on the y axis correspond to the absolute quantum yield, which is defined as the internal quantum yield ε in corrected from the absorption coefficient leading to the ε ex 181 , as shown below:

𝜀 𝑖𝑛 = 𝑁 𝑒𝑚 𝑁 𝑎𝑏𝑠 𝑎𝑛𝑑 𝜀 𝑒𝑥 = 𝑁 𝑒𝑚 𝑁 𝑒𝑥 = 𝜀 𝑖𝑛 ( 𝑁 𝑎𝑏𝑠 𝑁 𝑒𝑥 ) (7)
where N em is the number of photons of the emission light of the sample, N abs is the number of photons that are absorbed by the sample, and N ex is the number of photons of the excitation light from a Xe source. The present Chapter will discuss the effects of Eu 3+ -loading on OIH materials in order to probe local coordination of Eu 3+ ions and discover its effect on the PL of unloaded ureasil-polyether. In this way, FTIR measurements in transmission mode were carried out in the unsupported films (50 μm) of the OIH:Eu 3+ samples in both the (C-O-C) backbone and the amide region. The PL was measured using the OIH:Eu 3+ monoliths with a thickness around a few milimeters. The PL values were confronted with the polymer backbone conformation (gauche and/or trans) and investigated by FT-Raman.

The PL of the OIH:Eu 3+ complexes were also studied as a function of the UV-vis irradiation varying with the time of exposure. Nano-structural characterization was realized by SAXS in order to help us understand the PL dependence along with the UVvis irradiation.

4.2: Effect of Eu 3+ -loading in the thermal/structural properties of the OIH: On the other hand, the most significant effect resulting from the Eu 3+ -loading into OIH matrices is the appearance of a new band in the Amide region (1800 -1500 cm - 1 ) 185 , which can be divided into two contributions: Amide I and Amide II. The Amide I Wavenumber / cm -1

In the case of OIH:Eu 3+ complexes, the free carbonyl oxygen atoms which originate from this process coordinate with the Eu 3+ cations forming structures of Eu 3+ ---O = C (urea) probably involving short contact distances. Characteristic spectral changes, manifested as wavenumber shifts or band splitting, are a result of the coordination of polymer chains with guest cations. Analysis of the spectra of different Eu 3+ -loaded OIH di-ureasil matrices leads us to conclude that the complexation by chromophore molecules belonging to the OIH matrix happens by the oxygen carbonyl from the urea groups present in this kind of material. Thus Eu 3+ -(urea) complexes are probably responsible for the downshift of the band from 1641 to 1608 cm -1 193 .

In a different way, U-PPO 230 does not show a single peak at 1608 cm -1 , but rather, a displacement of the Amide I band to lower wavenumber values. The for this is that the U-PPO 230 OIH matrix has the higher portion of urea groups, showing a band intensity in the Amide I region that is 2 and 8 times higher than the U-PPO 2000 and U-PPO 4000 , respectively. This feature is accompanied by a smaller intensity for the band at 1110 cm - 1 by having the smaller number of (-CH(CH 3 )-CH 2 -O-) n monomer in the organic chains.

For instance, the Amide I region of U-PEO 1900 (Fig 4.4 (a)) displays an intense band around 1640 cm -1 and a shoulder at around 1680 cm -1 , attributed to hydrogen bonding and "free" C=O groups, respectively 194 . However, the second derivate of the curve reveals that the Amide I region is composed of three components and the Amide II shows a single intense band at 1560 cm -1 . In order to quantify these components, To get further information about the effect of the OIH matrix -Eu 3+ coordination and its effect on the conformational state of the poly(ether) chains (PE), FT-Raman was carried out in situ during heating from -85 °C to + 100°C, in the energy range from 700 to 1500 cm -1 corresponding to rocking, wagging and twisting modes of matrix it has been reported 197,198,199,200,201 that the torsional angle of polymer backbone becomes smaller than the average angle found in net PEO when a 3:1 complex was formed between PEO and a small metal cation, leading to the increase of the gauche/trans conformer ratio of the chains. For this reason, the growth of some bands at 809, 890, 1040 and 1140 cm -1 are stronger in the spectra of U-PEO 1900 :Eu 3+ complexes (more obvious at low temperature).

In for both Eu 3+ -unloaded and Eu 3+ -loaded, due its amorphous character even below 0 °C. peak with a maximum (q max ) at 2.13 and 1.49 nm -1 . This effect provides evidence for a strong spatial correlation between the regularly spaced siloxane cross-linked nodes 204 .

After Eu 3+ -loading, red SAXS curves showed a q max displacement of 1.63 and 1.33 nm -1 The broad band in the green-blue spectral range is ascribed to the convolution of the emission from NH groups from urea bridges and the emission originating from electron-hole recombination in the siliceous domains in the inorganic backbone 208,209,210 , which have already been observed in unloaded matrices 211 of similar hybrids 212,213 . In the λ em. > 425 nm region, five emission peaks lying at 578, 590, 615, 652 and 699 nm, belonging to the 5 D 0 → 7 F J (J = 0-4) Eu 3+ transitions can be observed [START_REF] Dahmouche | Investigation of new Ion-Conducting Ormolytes: Structure and Properties[END_REF] .

By increasing the time of UV-light irradiation, a decrease of intensity of all emission bands can be observed. The decrease in the broad band at 425 nm can be associated with polymer β-scission leading to a decrease in the number of spatially correlated siloxane nodes, as shown in Fig. 4.9, while the decrease of the narrow lines is a consequence of the polymer β-scission accompanied by the loss of Eu 3+ coordination with the carbonyl oxygen. The effect of photo-ageing in the OIH structure will be further discussed in Chapter 5.

The narrow line at 579 nm represents the 5 D 0 → 7 F 0 transition 116 -The presence of this electronic transition in both emission spectra of OIH:Eu 3+ complexes reveal a disordered-like complexation, as observed in oxide glass 108 . The 5 D 0 → 7 F 1 transition corresponds to a parity-allowed magnetic dipole transition, which is practically independent of the chemical environment 214 and therefore, it has been used for normalization. On the other hand, the 5 D 0 → 7 F 2 transition, called "hypersensitive" 215,216 , is a forced electric dipole (ED) transition, being a forbidden transition by the selection rules. However, the 5 D 0 → 7 F 2 electric dipole transition becomes allowed for molecules without centers of inversion because the Laporte's rule is relaxed due to odd parity terms in the ligand field Hamiltonian 209 . The emission strength of this transition is sensitive to the surroundings of Eu 3+ 217 , indicating that the Eu 3+ ions occupy a low symmetry site without an inversion center for both U-PEO 1900 :Eu 3+ and U-PPO 2000 :Eu 3+ . For this reason, the ratio between the intensities (I 0-j ) of the 5 D 0 → 7 F 2 and 5 D 0 → 7 F 1 transitions, I( 5 D 0 → 7 F 2 ) / I( 5 D 0 → 7 F 1 ), called the Judd-Ofelt parameters (Ω 1,2 ) 148, 218 , can be considered as a parameter to probe the "asymmetry" of the Eu 3+ sites 219,220 . Usually Judd-Ofelt intensity parameters are obtained from absorption data. However, in the case of Eu 3+ , the pure magnetic dipolar character displayed by the 5 D 0 → 7 F 1 transition makes it possible for the determination of the intensity parameters to be obtained from The low intensity found for the 5 D 0 → 7 F 3 is due to its forbidden origin by the selection rules, happening in a forced way through the electric dipoles 223 . At the same time, the "hypersensitive" transition, 5 D 0 → 7 F 2 , the band observed at 699 nm, ascribed to the 5 D 0 → 7 F 4 transition, is also a forced electric dipole transition, as defined by the selection rules. Therefore, its intensity (I 4 ) should become lower as its symmetry becomes higher. after irradiation of U-PPO 2000 :Eu 3+ . The band observed at 340 nm comes from the energy absorption of the organic ligands, while the band at 368 nm is due to the Eu 3+ cation excitation by the antenna effect 103 . The PL-QY for this material before the UVlight irradiation was found to be around 9%. On the other hand, the U-PEO 1900 :Eu 3+ material before UV-light irradiation showed a poor PL-QY value (QY ~1.5 %). The significant difference between these values points out the crucial role of the ureasil substituent's nature in the PL-QY features, particularly the hydrophilic/hydrophobic properties, where the water molecules typically found coordinate with the PEO backbone and can quench the Eu 3+ PL features.

After 1 h of UV-light irradiation, the U-PPO 2000 :Eu 3+ PL-QY decreases 45% from its initial value, accompanied by the intensity increase of three bands, located at 380, 395 and 465 nm. These bands are well-known in literature and are attributed to the 7 F 0 → 5 L 7 , 7 F 0 → 5 L 6 , and 7 F 0 → 5 D 2 Eu 3+ transitions, respectively. This kind of electronic transition is not characteristic to the Eu 3+ cation coordinated in a complex system environment without a symmetry center. As the time of the UV-light irradiation increases, the intensity of the bands from the Eu 3+ non-coordinated environment increases as well, showing a dependence ofEu 3+ -OIH matrices complexation on UVlight irradiation. This finding allows for the proposal of applying this material in the field of coatings as optical-markers and UV-sensors. Both polymer complexes showed narrow emission lines, ascribed to the 5 D 0 → 7 F j europium transitions, confirming Eu 3+ dissociation into the matrix. The poor PL-QY observed for the U-PEO 1900 :Eu 3+ complexes were shown to be ascribed to the PEO 1900 tgt helical conformation, which coordinates with water molecules, thus preventing an efficient ligand-metal energy transfer. On the other hand, U-PPO 2000 , with a transconformation, showed a reasonable PL-QY value and a good dependency on Eu 3+ -O carbonyl complexation as a function of the UV-irradiation time. The intensity decrease of the broad green-blue band and the narrow lines (ascribed to the 5 D 0 → 7 F j europium transitions) was enlightened. This new knowledge of lanthanide-containing materials combined with the excellent mechanical properties and bio-compatibility of OIH materials allows for their application in different fields such as UV-sensor coatings and biological optical-markers.

Introduction to the Chapter:

In this Chapter, we intend to evaluate the role played by the carbonyl oxygen atoms in the loss of coordination with Eu 3+ cations suggested by the visible red → blue transition in order to gain an in-depth understanding of these luminescent features, which were discussed in Chapter 4. We will analyze the FTIR spectral signature and photoluminescence properties of U-PPO of different molecular weights in the carbonyl range (1800 -1500 cm -1 ) for OIH:Eu 3+ thin films as a function of the duration of artificially accelerated UV-irradiation (λ ≥ 300 nm). Our efforts were focused on OIH:Eu 3+ complexes based on PPO, aiming to evaluate the effect of the polymers' molecular weight on the photo-aging rate. U-PEO 1900 :Eu 3+ was not discussed in detail due to the complexity of the mass transport properties in semi-crystalline polymers.

Therefore, the detailed studies that were carried out refer to the set of amorphous polymers that can give us more reliable results.

Effect of Eu 3+ -loading on photo-degradation:

The UV-vis irradiation at λ > 300 nm for the Eu 3+ -unloaded and Eu 3+ -loaded OIH material matrices of the U-PPO films (thickness = 50 μm) (wt. = 230, 200 and 4000 gm -1 ) caused notable modifications in the IR spectra. However, UV-irradiation had to be limited to moderate extents of oxidation times because the samples completely degrade in a very short amount of time, especially in the case of thin films.

For polymers, as in the case of PEO and PPO, the first step of photo-oxidation, occurring at λ > 300 nm, is the formation of hydroperoxides (Fig. respectively. In both cases, for U-PPO and Eu 3+ U-PPO, it is observed the formation of a new IR band at 1720 cm -1 with a shoulder at 1740 cm -1 with UV-irradiation time.

For U-PPO 2000 , the IR spectra during 10 hours of UV-irradiation (Fig. 5.3 (a))

shows the formation of a new absorption band in the carbonyl domain, whose intensity increases with the time of the UV-irradiation, with a maximum at 1720 cm -1 and a shoulder at 1740 cm -1 , which are the contribution of different carbonylated species, from the OIH material photo-ageing, resulting in the photo-products of the polymer oxidation.

For OIH:Eu 3+ complex based on PPO, the IR spectra (Fig. 5.3 (b)) shows the formation of the same absorption bands with a maximum at 1720 cm -1 and a shoulder at 1740 cm -1 , whose intensity increases with the UV-irradiation duration. This reveals that the same oxidation products are formed in both cases. On the other hand, the IR band at 1608 cm -1 which corresponds to the Eu 3+ complex and previously characterized as ʋ(C=O) from the Eu 3+ -O carbonyl complexation, decreases whereas two bands appear at 1620 and 1575 cm -1 with the increase of the UV-irradiation time. This phenomenon suggests a decomplexation of Eu 3+ cations with the U-PPO ligands upon UV-vis irradiation, once these maximums have already been attributed to the Amide region, originated from the loss of the Eu 3+ -OIH coordination with the increase of UV irradiation time. Absorbance / a. u. Other feature found by comparing the FTIR photo-aging results of the U-PPO hybrid prepared with PPO of different molecular weights (wt. 230, 2000 and 4000 g.mol -1 ), is the effect of the Eu 3+ loading on rate of photo-oxidation products formation.

The rates of photo-oxidation of the unload and Eu 3+ loaded U-PPO, Fig. 5.4, respectively, can be compared by the subtraction of the band at 1720 cm -1 . In case of the thin films, with the same thickness, this rate can be directly compared with each other. weight is observed. The curve profiles of carbonylated formation (Fig. 5.4) are sensitive to the PPO molecular weight and the Eu 3+ -loading as well. U-PPO 2000 Eu 3+ -unloaded was the OIH material with the higher carbonylated products formation, while the U-PPO 230 Eu 3+ -unloaded was the lower one 228 .

Figure 5.4: Variation of absorbance at 1720 cm -1 as a function of UV irradiation time (photooxidation at λ > 300 nm, 60 ºC) for the U-PPO films with different molecular weights (230, 2000 and 4000 g.mol -1 ), Eu 3+ -unloaded (full circles) and Eu 3+ -loaded (empty squares). From Fig. 5.6 (a) and (b), it is observed that there is an intensity decrease of the main oxidation band at 1720 cm -1 correlates with an increase of two bands at 1680 cm -1 and 1640 cm -1 . These bands originated from the reaction between ammonia with U-PPO 2000 photoproducts. The host structure reaction (Fig. 5.6 (a)) leads to an increase of absorbance at 1680 cm -1 (peak # 1) attributed to amide groups, which are formed by the reaction between ammonia and ketone (1720 cm -1 ) 224 :

On the other hand, unclear in Fig. 5.6 (a), a new band referred to the amides formed from the reaction of NH 3 with ester. In fact this new band is expected to be in the same wavenumber range of the Amide groups that already exist in the OIH material structure 185,229 , hidden from the observation of the band formed from the ammonia -photoproducts reaction. However, in Fig. 5.6 (b), it was possible to observe the band at 1640 cm -1 due to the presence of the Eu 3+ -O carbonyl complexation band at 1608 cm -1 .

This result helps to prove the ester groups to be one of the PPO photoproducts, Fig.

O C R OR' + NH 3 O C R NH 2 ν(C=O) 1680cm-1 (a) (b)
Unloaded and Eu 3+ -loaded OIH U-PPO materials showed two different, main photoproducts, confirmed by the NH 3 reaction; one of the photoproducts comes from a hydroperoxide β-scission resulting in ketone groups, and the other one comes from a cage reaction forming ester groups, leaving a -CH 2 ° radical (Fig 5 .3).

Red → Blue photoluminescence transitions and its application:

The loss of Eu 3+ coordination with the UV irradiation allow for these complexes to have a transition in the visible range from red to blue. The red → blue transition (Fig. 5.8) is responsible for the second effect on the polymers photo-oxidative behavior. This effect came from the efficient intermolecular energy transfer of the UV-light absorbed, realized by the urea organic chromophore -NH-C(=O)-NH-to the luminescent center. These results give the material the possibility to be applied as optical marker coatings for monitoring exposure to excessive UV-light for packaging.

For that, the photoluminescence of Eu 3+ -loaded OIH matrices as a function of UV irradiation time was carried out to measure the energy transfer from the organic ligand to the Eu 3+ luminescent center. The quantification of the absolute PL quantum yield values (%) recorded for U-PPO:Eu 3+ complexes with different molecular weights, considering the overall luminescence of the Eu 3+ cation, as function of the UV-irradiation time, is reported in Fig. 5.9. U-PPO 2000 :Eu 3+ and U-PPO 4000 :Eu 3+ showed a PL decreasing from 9% to 4% and 8 % to 3%, respectively, after 1 h of UV-light irradiation. U-PPO 230 :Eu 3+ does not show a considerable value of PL in the red emission range, which may be explained by the high europium concentration in the matrix, thus causing an inefficient energy transfer. U-PPO 2000 :Eu 3+ showed the best performance in the field of Eu 3+ energy transfer. Following these results, this U-PPO material is the most appropriate for this kind of application, combining its PL properties with the excellent physical-chemical properties and its remarkable capacity to holding its structure during high wavelength irradiation.

Partial Conclusions:

The aim of this Chapter was to utilize of the knowledge of polymer degradation mechanisms to confirm the coordination of Eu 3+ -O carbonyl from urea groups and to complement the results obtained in Chapter 4. Room temperature FTIR of the OIH thin films showed a 1608 cm -1 band intensity decrease that depended on the UV-vis irradiation time. These results are coherent with the loss of Eu 3+ coordination when the materials are exposed to intense UV-light. The loss of Eu 3+ coordination reveals a dependence of PPO molecular weight present in OIH materials, leading to different photo-degradation kinetics rates.

These set of results enable proposing a mechanism of degradation. Furthermore, the difference in the kinetics parameters after Eu 3+ -loading shows a slower rate of βscission reaction compared with the Eu 3+ -unloaded OIH materials, allowing us to propose that the presence of Eu 3+ atoms protects the OIH material from β-scission of organic chain.

The formation of new absorption bands at 1720 and 1740 cm -1 with the increases of UV-vis exposure allowed the OIH photo-products determination by the ammoniac chemical treatment of the photo-degraded OIH materials. It was observed the formation of formate and ester as the main photo-products, even to the OIH:Eu 3+ complex, from the hydroperoxides organic chain β-scission and cage reaction, respectively. The satisfactory value of PL absolute quantum yield for the U-PPO 2000 :Eu 3+ and U-PPO 4000 :Eu 3+ before the UV-vis irradiation accompanied with their quickly loss of Eu 3+ coordination showing to own a red → blue PL transition. The Eu 3+ β-scission chain protecting make these OIH:Eu 3+ complexes emerging materials for application as optics markers and/or packaging monitoring of intense UV exposure.

Introduction to the Chapter:

This Chapter will focus on the effect of Li + -loading on the thermal, structural and electrical properties of OIH matrices based on PEO 1900 , PPO 2000 and U x PEO 1900 :U-1-

x PPO 2000 blends. The thermal properties were analyzed by DSC and the effect of blending in the melting of the semi-crystalline phase and glass transition temperature, T g , is discussed. The thermal events are compared with their structural features by room temperature FTIR spectroscopy and in situ monitoring during programed temperature variation using time resolved Raman spectroscopy and SAXS. This set of results allowed for the correlation of nano-structural features and ionic conductivity of OIH with the polyether backbone conformation, the PEO crystallinity, and the amount of PPO in the hybrid blend. The ionic conductivity was carried out by impedance spectroscopy for the OIH:Li + electrolytes monoliths. This kind of study allowed for the proposal of the Electrical Equivalent Circuit and the relationship between the circuit components and the OIH structural building blocks. The evolution of T g with the composition for unloaded and Li + -loaded samples is shown in Fig. 6.2. The comparison of unloaded and Li + -loaded samples reveals a high value of T g for the OIH:Li + . This feature suggests that the polymeric organic chain is interacting with the guest cation by the ether-type oxygen, thus leading to a more rigid organic chain with lower organic chain motion compared to the unloaded OIH matrices [START_REF] Chaker | Correlações entre estrutura e propriedades de condução iônica em materiais híbridos siloxanopoli(propileno óxido), dopados com sais de sódio e potássio[END_REF] . On the other hand, as the PPO 2000 fraction increases in the blend, the T g value decreases in a similar way for the unloaded and Li + -loaded materials. This finding suggests that partition of the Li + atoms between the two polymers is almost unaffected by the blend composition. implies that the polyether component of the hybrid can form a thermodynamically stable, compatible mixture at temperatures above the melting point, and that the amorphous phase acts as a diluent of the crystalline polymer 233 . In order to confirm this crystalline polymer/amorphous diluent behaviour, the D C of the PEO 1900 in the hybrid blending was calculated from the relationship between the observed melting enthalpy (ΔH m ) and the standard melting enthalpy for 100 % crystalline PEO (ΔH p ) (188.9 J/g) [START_REF] Liang | Charge-tunable insertion process of carbon nanotubes into DNA nanotubes[END_REF] .

Thermal behavior:

𝑫 𝒄 (%) = ∆𝑯 𝒎 ∆𝑯 𝒑 𝒙 𝟏𝟎𝟎% (𝟗)

(b) (a)
On the other hand, Li + -loading in the OIH matrix does not cause an abrupt damage in the Amide region, as was observed in the case of the Eu 3+ cations (Fig 4.4 (d)). The effect of the hydrogen-bonding in the U-PEO 1900 Amide region after a Li + -addition is shown in Fig 6 .5. "Amide II" The three components of the Amide I region for U-PEO 1900 (Fig. 6.6 (black)) are dominated by an intense band centered at 1564 cm -1 . As discussed earlier, these components are attributed to the ordered urea/urea, urea/poly(ether) hydrogen bonding.

On the other hand, in the case of the same OIH matrix Li + -loaded,(Fig. 6.6 (blue)) the area maxima are observed for the band at 1656 cm -1 , ascribed to disordered urea/poly(ether), poly(ether)/poly(ether) hydrogen bonding. These results are consistent with the amorphous nature of U-PEO 1900 -Li + -loaded observed by DSC. However, U-PEO 1900 -Li + -loaded, showed a small area integral (14 %), ascribed to an ordered hydrogen bond. Considering that the O ether in the (O-C-C-O) structural backbone is interacting with Li + cations which restrain the PEO helical conformation, the presence of this component could come from urea/urea aggregates. This effect will be further discussed below.

In the case of the component at 1674/1680 associated to the "free" C=O, it is observed that the area remains invariant with the Li + loading, indicating that Li + cations do not interact with the OIH matrix via the polar oxygen-carbonyl. This preferable configuration helps to explain how a wide concentration of guest metallic cations can be complexed by these poly-ethers.

As the temperature increases, the helical PEO backbone is lost (at T >T f ) and a new, broad band arises at 810 cm -1 due to the trans backbone conformation (CCOC or COCC).

In the same way, the bands observed at 1040 and 1242 cm -1 in the gauche conformation are attributed to ν s (C-O-C) and to in-plan C-H deformations. The increments of temperatures above T f cause the loss of these band definitions and a broad band with a displacement for lower frequency values is observed. These changes can be the result of the breaks in intermolecular hydrogen bonds, found in the ordered helical configuration 235 .

The evolution of the U-PEO 1900 :Li + loaded Raman spectra as a function of the temperature increase from -85 to 100 °C is shown in Fig. 6.7 (b), which reveals an intense band at 740 cm -1 associated with the free anions [C 2 F 5 NO 4 S 2 ] -35 , which reveal the inorganic lithium salt dissociating into the OIH matrix. Also, two weak bands are observed at 1040 cm -1 , which can be associated with the weak interaction between the triflate ions with the OIH matrices, while the band at 1067 is due to the bi-or tridentate aggregate formation (Li 2 (CF 3 SO 3 )] + or [Li 3 (CF 3 SO 3 )] 2+ ) 236 . The absence of the band at 1077 cm -1 in the range of all temperatures excludes the presence of crystalline lithium salt. In this kind conformation, the metal coordination is similar to the crown-ether, in which the Li + cations are typicallycoordinated by 5 ether-type oxygen atoms. This crown-ether Raman shift / cm -1 conformation deviates from PEO helical conformation, usually found in bulk PEO crystalline structures, giving the material an amorphous character. Moreover, the addition of small cations in the form of salts has been shown to hinder PEO crystallinity, which is in agreement with DSC and FTIR results. The comparison between the spectra displayed in Fig. 6.8 (a) and (b) reveals a new band at 810 cm -1 accompanied by a displacement of the band at 870 to 865 cm -1 after Li +loading, indicating that the presence of the guest cation disturbs the system even for a trans conformational backbone structure Furthermore, the bands observed at 1048 and 1016 cm -1 are attributed to the Si-OCH 3 vibration mode of unloaded U-PEO 1900 and U-PPO 2000 , respectively. These stretches are ascribed to the tri-siloxane (Si-O 3 ), found around 1010 -1020 cm -1 , easily distinguished from the tetra-siloxane (Si-O 4 ) typically found at 1080 cm -1 . The presence of the tri-siloxane bands in both OIH matrices prove the poly-condensation of the alkoxisiloxanes existing at the end of the OIH materials.. The bands at 1450 and 1473 cm -1 and 1406 and 1456 cm -1 , for the U-PEO 1900 and U-PPO 2000 , respectively, are usually attributed to the CH and CH 2 symmetric deformation and asymmetric CH 3 230 . However, the O-CH 2 deformations can also contribute to this absorption 237 . U-PPO reveals a band at 1350 cm -1 , which is not observed for U-PEO 1900 . This band is characteristic of the tertiary carbon CH deformation coupled with the symmetric deformation modes of the two adjacent carbons 233 . Table 6.3 shows the attribution of the main bands observed in Raman spectra of different OIH materials. Raman shift / cm -1 The modifications of the nano-structural features of OIH materials caused by the addition of Li salts and the composition of Ux PPO 2000 :U-1-x PEO 1900 blends were studied by SAXS measurements carried out both at room temperature and during heating.

The effect of the Ux PPO 2000 :U-1-x PEO 1900 blend composition on the nano-structural features of hybrids is evidenced from the comparison of the room temperature SAXS pattern displayed in Fig. 6.9 (a). All SAXS curves exhibit a broad peak with a maximum (q max ) centered at 1.75 and 1.64 nm -1 for the unblended U-PEO 1900 and U-PPO 2000 samples, respectively. This maximum is due to effect of scattered interference resulting from spatial correlation of regularly spaced siloxane cross-link nodes 204 . The average correlation distance between two adjacent siloxane nodes (ξ) is estimated from the peak position, q max (ξ = 2π/q max ) 205 , 3.60 and 3.83 nm for U-PEO 1900 and U-PPO 2000 , respectively. OIH blends showed intermediate ξ values. The increase of both ξ and peak intensity as the amount PPO 2000 increases reflects the differences in the polymeric chain length and the electron density between the siloxane nodes due to the formation of less compact structures. In addition, some SAXS patterns exhibit an ill-defined second peak maximum located at a middle q-range, (q max ~ 0.58 nm -1 ). This maximum, corresponding to a Bragg distance of ξ sc -spacing = 10.8 nm, has been well associated with the long period distance of superstructures formed by lamellar arrangements and amorphous parts of semi-crystalline (SC) PEO homo-polymers 238 .

In the case of OIH:Li + materials, Fig. 6.9 (b), similar SAXS patterns are observed, indicating that Li + -loading does not lead to considerable modifications on the general nano-structural features of OIH materials. However, it is evident that the displacement of the siloxane correlation peak to higher q values after Li + -loading, leads to an increase of ξ from 3.20 to 3.59 and from 3.25 to 3.83 nm for U-PEO 1900 and U-PPO 2000 , respectively, accompanied by a decrease in I (q max ). This behavior is accompanied by decreases of the peak intensity, showing evidence that Li + additions lead to the decrease of the electron density contrast between the siloxanes nodes and the polyether matrix.

This finding allowed us to conclude that the interaction between the OIH matrix and the guest cation occurs by the polar ether oxygen-type present in the segments of the PEO or PPO chains.

The second maximum at the middle q-range is ascribed to the long period distance of superstructures 234 , which was also observed for some blend compositions of the OIH:Li + materials. The presence of this maximum was found for blends with PPO 2000 fraction x = 0.5 and 0.8. A possible explanation for this phenomenon is the presence of the amorphous PPO 2000 content in the homogenous OIH mixture, which contains a crystalline fraction of PEO 1900 .The presence of semi-crystalline PEO 1900 in Li + loaded blends can be explained by the preferential dissolution of Li -salts by the U-PPO 2000 chain matrix, thus leading to the depletion of Li + cations in PEO 1900 chains withe helical conformations. The characteristic melting event in the presence of semi-crystalline PEO 1900 was inexplicably masked in the DSC trace of Li + loaded blends (Fig.

6.1).

The above results are in reasonable agreement with the DSC and also indicate that the nanostructure of the hybrid blends could be described by the existence of an extensive mixture between the amorphous fraction of PEO 1900 and PPO 2000 chains and a small fraction consisting of lamellar domains associated with the PEO 1900 crystallinity even for OIH:Li + blends. In fact, all Ux PPO 2000 :U-1-x PEO 1900 hybrid blends are transparent, indicating the absence of macroscopic phase separation. 

Evolution of the SAXS patterns during heating;

In order to better understand the effect of the presence of crystalline PEO 1900 in the nano-structural features of OIH matrices, in situ SAXS measurements were carried out during heating with a range from -100 to +100 °C. Fig. 6.10 presents the threedimensional log-log SAXS curves stacked with a temperature interval of 5 °C for the U-

0.1 1 20 % 50 % 80 % 0 % q (nm -1
)

I (q ) 100 % U- x PPO 2000 : U- 1-x PEO 1900 U-PPO 2000 / % q max low-q 0.1 1 q (nm -1
)

I (q) 0 % U- x PPO 2000 :Li + : U- 1-x PEO 1900 :Li + 20 % U-PPO 2000 / % 50 % 80 % 100 % q max low-q q / nm -1
q / nm -1 middle q-range middle q-range PEO 1900 hybrid indexed with the DSC calorimetry trace. At low temperatures, -100<T <~ 25 °C, the SAXS curves display two maxima, attributed to the long distance period of semi-crystalline PEO (q < 1 nm -1 ), and to spatially correlated siloxane (q > 1 nm -1 ).

The vanishing of maxima at the middle q-range for temperatures above the melting q / nm -1 q / nm -1 I (q) I (q) q / nm -1 q / nm -1 Fig 6 .12 displays the temperature dependency of the average correlation distance calculated from the maximum of the peak position for U-PEO 1900 and U-PPO 2000 unloaded and Li + -loaded materials. For all samples the threshold of the thermal expansion are in agreement with the T g value found from DSC. The invariance of the average correlation distance below T g is consistent with the rigidity of the polymeric framework in the glass state, which relaxes and expands for T >T g . After T g , the slope of the thermal expansion curves (θ), distinctly increases for U-PEO 1900 , unloaded and Li + -loaded. Moreover, an abrupt increase of ξ is observed between 0 and 10ºC for unloaded U-PEO 1900 , evidencing a strong contribution of Li + -H 2 O interactions on the relaxation of the polymer chain. The slope of the thermal expansion curves for the unloaded U-PEO 1900 and U-PPO 2000 tend to approach the same final values (T > 50ºC).

The same behavior is observed for Li + -loaded samples. 

Quantitative evolution of the nano-structural parameters;

A common feature observed in log-log SAXS patterns of all OIH materials is the linear decay of intensity found at the low-q range. In this case, the scattered intensity follows a power law, I(q) = q -α , characteristic of Porod's law, which gives information concerning the interface structure 240 . It is expected that this power law contributes in a constructive way to the intensity of the entire SAXS curve. According to obtained quantitative information about the evolution of the structure of long period semicrystalline materials and the spatially correlated siloxane domains, the experimental SAXS curve was subtracted from the power law decay (Porod law: I= K q  ) observed at the low q-range. The linear Porod subtraction was carried out according to the following equation (10), and the results were plotted in Fig. 6.13:

𝐼(𝑞 𝑡ℎ𝑒𝑜𝑟𝑖𝑐 ) = 𝐾. 𝑞 𝛼 + 𝐵 (10)
Where K and α represent the linear and angular coefficient obtained from Porod´s region and B is a high q-range constant due to the diffuse scattered intensity.

The corrected U-PEO 1900 SAXS curves using equation 9 are displayed in Fig. 6.13(a) and (b), which reveal two well defined maxima associated with the semicrystalline domains of PEO 1900 (middle q-range,Fig. 6.13(a)) and with the correlation peak of the siloxane nodes (high q-range, Fig. 6.13(b)). The first one, Fig. 6. 13(a) shows a continuous increase of intensity until the H 2 O fusion temperature, followed by a pronounced decrease until a complete disappearance at the PEO 1900 melting point.

Moreover, the average long period distance ξ sc is invariant below T g and shows a linear expansion between T g and ~10 o C. This finding suggests that the water molecule participates of the PEO 1900 lamellae crystallite organization by hydrogen bonding with the polar oxygens present in the amorphous polymer chain segments, leading to an increase in the electron density contrast between the crystalline lamellae and the amorphous phase as the temperature increases from T g to 0 o C. On the other hand, the siloxane correlation peak measured at the lowest temperature (curve blue in Fig. 6.13 (b)) can be separated by the naked eye in at least two maxima. As temperature rises, the intensity of the component at the low q-side becomes higher, and we are no longer able to separate it in two maxima. In the case of U-PEO 1900 :Li + , the corrected SAXS curves in the region of the correlation peak of siloxane nodes (high q-range), Fig. 6.13 (c) displays low intensity, hampering the deconvolution component through the multiple peak fitting procedure. q max / nm -1

0 1 I(q experimental ) -I(q theoric ) q / nm

Peak Analysis

BaseLine:Line Any maximum found in the middle-q range (Fig. 6.18 (a)) for the blend with 0. q / nm -1 q / nm -1 q / nm -1 q / nm -1 q / nm -1 q / nm -1 blend with 0.8 PPO 2000 (Fig. 6.18(b)), a very broad band with low intensity is found at the middle q-range for all temperatures. The origin of this phenomenon is unclear and a speculative explanation is the non-homogeneus partition of Li + in the OIH blend. However, Fig. 6.18 (c) and (d) shows a dissimliar behavior for the blend with 0.5 PPO 2000. . In the case of the Li + unloaded blend (Fig. 6.18 (c)), the emergence of the maximum at the middle q-range is found in the temperature range between 0 and 25 o C.

For the unloaded Li + blend, this maximum at the middle q-range is found at all temperatures. In a different way, for the blend with 0.2 PPO 2000 , the middle q-range maxima is present for the entire low temperature range (T< 25 o C) of the unloaded sample (Fig. 6.18 (e)) and is absent for the Li + -loaded one (Fig. 6.18 (f)). As expected, the slope of the sample with U-PEO 1900 is almost 10 times higher than the other OIH samples. A classical mixture law involving intensive properties, like the linear expansion coefficient, is not followed for the hybrid blends. The experimental values are lower than the calculated values from the mixture law, indicating that the slope of PEO 1900 for both unloaded and Li + -loaded have a lower contribution in the thermal expansion of OIH blend materials.

- The 6.20(c) and (e). In fact, we can observe the emerging intensity of the middle q-range peak after the H 2 O fusion temperature followed by a pronounced decrease near the PEO 1900 melting point, again revealing the participation of hydrogen bonding from the H 2 O in the OIH blend.

On the other hand, the SAXS curves of Li + -loaded OIH blends (Fig. 6.20(b), (d) and (f)) show the intriguing presence of the middle q-range maxima in all studied temperatures, despite the amorphous character of these samples revealed from DSC (Fig 6.1). This feature coexists with the broad siloxane correlation peak of very weak intensity, which prevents the deconvolution of the band by a Gaussian function. These findings reveal that Li + cation incorporation causes drastic changes in the nano-structure of OIH materials. Afterwards, the comparison between the unloaded matrix with their respective Li + -loaded OIH matrix will be qualitative.

Thus, the quantitative nano-structural parameters of Ux PPO 2000 :U-1-x PEO 1900 was determined only for Li + unloaded Ux PPO 2000 :U-1-x PEO 1900 OIH blends and the results are discussed in the next section. q / nm -1 q / nm -1 q / nm -1 q / nm -1 

Evolution of nano-structural parameters of blend;

The Gaussian components from the siloxane correlation peak of Ux PPO 2000 :U-1-

x PEO 1900 prepared with 0.8 U-PPO (Fig. 6.20 (a)) was not calculated because the SAXS patterns are essentially temperature invariant. Furthermore, there is no evidence of the maxima associated with the average long period distance (ξ SC ). Therefore, our attention was focused on the Gaussian fitting for OIH blends with x = 0.5 and 0. PPO 2000 and the results are shown in Fig. 6. 21 and 6.22. Fig. 6.21(a) shows the evolution of the area of each Gaussian component of the siloxane correlation peak of U-0.5 PPO 2000 :U-0.5 PEO 1900 OIH blend as well as the area of the middle q-range peak associated with the semi-crystalline super-structure of PEO 1900 as a function of the temperature. Another observation can be made in U-PEO 1900 homohybrids (Fig. 6.17 0.02 is also invariant with the temperature and is lower than expected for cubic packing of the siloxane node Figs. 6.22 (b). These results show that adding PPO in the OIH blend disturbs the cubic arrangement of the siloxane nodes. 3.2). The numbers (between 6 and 1) shown inside the figures give the log 10 (signal frequency) for the corresponding point. In a temperature range below the material's T g , the impedance curves show an incomplete semicircle due to the high resistivity of OIH:Li + . As expected, these results demonstrate that the cation mobility assisted by the segmental motion of chains is negligible for polymers in the glass state.

The polymer chain rigidity in this range of temperatures blocks the ionic transfer through the polar ether-type oxygens hampering the macroscopic ionic conductivity.

However, in the same range of temperatures, a complete semi-circle for the U- It has been reported that the high frequency semi-circle does not appear in impedance plots for ion-facilitated plasticized polymer electrolytes 243 . The range of temperatures which the semi-circle disappears coincides with PEO 1900 semi-crystalline melting, observed by DSC and SAXS (as a function of the temperature). This phenomenon confirms that the fully rubber structure of OIH:Li + monoliths behave similar to a liquid electrolyte 244,245 . Comparing the set of Nyquist diagrams and the thermo-event revealed

for DSC, it is inferred that ionic conductivity values depend on two factors: i) The temperature, due to the increase of free volume with the temperature. In this process, the segmental motion of the chain helps the cation hooping between the ether-type oxygen, thus increasing the Li + diffused through the OIH material 246 and ii) the dependency of T g electrolytes, since it is well known that the lower the T g value is, the higher the free volume, υ f , will be.

In order to correlate the thermal and the nano-structural features with the ionic transfer properties of OIH:Li + , an in depth analysis by Electrical Equivalent Circuit (EEC) was employed and the main results are shown in Figs. 6.28 and 6.29. Different EEC were considered depending on the OIH blend composition and temperature.

As discussed above, PEO 1900 is a semi-crystalline polymer, having helical and ether crown conformation in equilibrium at room temperature (T < T m ). From the nanostructure point of view, the SAXS results indicate the coexistence of full amorphous and periodic semi-crystalline superstructures on the blend rich in PEO 1900 . Based on these findings, in a temperature range between T g and T m of Li + -unloaded PEO 1900 , there was a consideration of an EEC formed from the connection in series with three parallel elements related to resistance and constant phase elements -CPE (denominated as -RQ-

). In this case R represents de specific electric resistivity of the material and Q is a charge accumulation when a voltage (V) is applied through a sandwich capacitor (C) constituted of two parallel electrodes with an area (A) defined separated by a distance (l) in the vacuum. The relationship is defined as: 11) where ε o is the vacuum dielectric constant (8.885x10 -12 F.m -1 ) and C the system capacitance (Farads -F).

𝑄 = 𝜀 0 𝐴 𝑙 𝑉 = 𝐶𝑉 (
The impedance data and ECC fitting attained at -10 °C for U-PEO 1900 :Li + is shown in Fig 6.27 (a). According to previous results, we strongly believe that the first parallel According to the -RQ -RQ -equivalent circuit, the impedance spectra of all

x PPO 2000 : 1-x PEO 1900 blend compositions can be explained by two different hypotheses These equivalent circuit models were applied to determine the specific bulk conductivity (σ s ) of U-PEO 1900 :Li + , U-PPO 2000 :Li + and x PPO 2000 : 1-x PEO 1900 blends in the entire range of temperatures. The σ s is inversely proportional to the specific bulk electrical resistivity (ρ) since it is also dependent of the geometry of the sample. electrolytes with the temperature is in terms of the Arrhenius (ln(σ s ) vs. 1000/T (K)) plots.

The observed linear behavior suggests that the thermally activated process follows an Arrhenius-type expression 250 :

𝜎 𝑠 = 𝜎 0 𝑒𝑥𝑝 -𝐸𝑎 𝑘𝑇 ⁄ (12) where σ 0 is a pre-exponential factor, T is the temperature in Kelvin, E a is the activation energy of the conduction process and k is the Boltzman constant (8.614x10 -5 eV.T -1 ).

The Arrhenius plot of the U-PEO 1900 :Li + material displays three different linear regimes;

i) from -90 °C to -55 °C, where the conductivity is almost independent of the temperature and the activation energy is close to zero (E a = 0.04 eV), which is consistent with the rigidity of PEO 1900 in the glass state (T<T g ); ii) between T g and 15 °C, a linear step is observed with E a = 0.3 eV); and iii) the third linear step is observed above 20 °C, which has the highest slope (E a = 0.4 eV). These steps are in agreement with the RC component of the proposed EEC above.

These two steps with nearly the same slope values are observed for x PPO 2000 :Li + :U-1-x PEO 1900 blend with x = 0.2 and 0.5 U-PPO 2000 . A single linear behavior with a lower activation energy (E a -0.19 -0.22 eV) is found for OIH:Li + blend samples with a high amount of PPO 2000 (x = 0.8 and 1), suggesting a single transport mechanism in the entire temperature range. This different behavior of thermo-activation of ionic conductivity suggests that the presence of poly(propylene oxide) chains play an important role in the conduction mechanism. The isothermal variation of the ionic conductivity with PPO 2000 fraction in U-

x PPO 2000 :Li + :U-1-x PEO 1900 :Li + blends is presented in Fig. 6.31. The ionic conductivity of U-PEO 1900 :Li + varies between 3x10 -8 Ω.cm -1 at -90 °C and 8.5x10 -4 Ω.cm -1 at approximately 100 °C (370 K). The ionic conductivity of blends with PPO 2000 fraction higher than 0. The overall crystallinity of PEO is reduced in the presence of salt ions. A crown-ether conformation, which favors the amorphous state of PEO 1900 is considered to be the primary reason of suppressed its crystallinity. Ionic room temperature conductivity shows the highest value for the U-PEO 1900 :Li + (σ s ~ 5x10 -5 Ω.cm -). The conductivity decreases for the PPO 2000 x = 0.2 blend, as a result of a decrease in the number of active carriers transfer, was attributed to an increase in the degree of lithium content at the PEO 1900 fraction and an increase of it rigidity. It is found that the PPO 2000 polymer is not a good candidate for plasticizers for lithium batteries in high values of temperature. On the other hand, PPO 2000 addition results in a significant increase in the ionic conductivity of the electrolyte at lower temperatures. The best combination of ionic conductivity and mechanical properties, at low temperatures (T < 0 °C) was obtained for the OIH:Li + blends monoliths with high PPO 2000 fraction x = 0. confirmed their quick loss of Eu 3+ coordination. On the other hand, the properties of lanthanide-containing materials were found and their visible red → blue PL transition allowed for the proposal of their application as UV-sensors and biological optical-markers, as well as optics markers and/or packaging monitoring of intense UV exposure.

In a different way, Li + cations show drastic changes in the polymer O-CH 2 -CH 2 -O backbone chains, which confirm the solvation of Li + by ether-type oxygen atoms. This induces the reduction of PEO crystallinity, confirmed by DSC, Raman, and SAXS measurements. The evolution of nano-structure with temperature revealed the participation of water molecules in the lamellae crystallite organization, leading to the increase of the electron density contrast between the crystalline lamellae and the amorphous phase as the temperature increases from T g to 0 o C. For OIH:Li + materials, the water molecule has the role of mediator in the Li + ---H 2 O---O ether interaction, and the trans crown-ether conformation (amorphous state of PEO 1900 ) was considered to be the primary reason for the loss of U-PEO 1900 crystallinity.

For OIH blends, DSC measurements reveal that the semi-crystalline PEO 1900 is embedded by the amorphous fraction of the PPO 2000 . However, the evolution of the nano-structure reveals that these materials do not obey a mixture law.

The best room temperature ionic conductivity was found for the U-PEO 1900 :Li + (σ s ~ 5x10 -5 Ω.cm -) sample. The best combination of ionic conductivity and mechanical properties at low temperatures (T < 0 °C) was obtained for OIH:Li + blend monoliths with high PPO 2000 fraction x = 0.8 and 1. U-PEO 1900 :Li + showed a form resembling the RQ -RQ -RQ ECC model, ascribed to the PEO 1900 helical conformation, amorphous conformation and electrode charge transfer. U-PPO 2000 :Li + and OIH blends showed a form resembling the RQ -RQ model, suppressing the contribution of PEO 1900 helical conformation. The semi-crystalline PEO 1900 melting has an important role in ionic conductivity because for T > T m , the solid electrolyte behaves like ionic liquids and the RQ -RQ model is no longer satisfactory to fit the experimental results.

The distinct local coordination for the different metal cations in these OIH matrices reveal a new and interesting property of these OIH multifunctional materials, which is the possibility of combining the ionic conductivity of the polyelectrolyte with their photoluminescent properties. This finding can further increase the fields of application of OIH materials. However, some studies need to be carried out to better understand the role played by water molecules in structural properties of U-PEO materials.

Chapter 8:

  Figures List # pg 2.1 Griffon: Hybrid creature from Greek mythology. 2.2 Schematic representation of class I (a) and class II (b) OIH materials 2.3 Transparent Siloxane-Poly(ether) hybrid materials, based on PEO and PPO polymers. The magnification of the crosslinking nodes exemplifies the Si-O-Si crosslinking structure network of the matrix 2.4 Dependency of the Volume with the Temperature for a crystalline (curve 1) and non-crystalline material (curve 2).

2. 14

 14 (a) U-PPO 2000 OIH matrix (blue emission) and U-PPO 2000 OIH:Eu 3+ complex (red emission) developed at this thesis and (b) CIE chromaticity diagram of a generic support matrix, doped with different Ln 3+ , showing the photoluminescence dependency of the lanthanide cation. 2.15 Schematic diagram of the Antenna Effect by the organic ligand with an efficient energy transfer to the lanthanide center 2.16 Acid (a) and Basic (b) catalysis reaction mechanism to the siliceous alkoxide. 3.1 Schematic diagram of the different OIH -matrices with their two polar oxygen active sities, I: O ether and II: O carbonyl , respectively 3.2 Schematic representation of the synthesis of the U-PEO 1900 and U-PPOs n OIH, Metal-unloaded, Li + -loaded and Eu 3+ -loaded OIH materials. An analogous process was adopted in the synthesis of the OIH materials from POs 230, 2000 and 4000 (n = 2.3 and 68, respectively) 3.3 DSC time and temperature for thecontrol program 3.4 (a) Photograph of the SEPAP 12/24 chamber during activity and (b) metallic sample holder with a hollow center 3.5 U-PEO 1900 (left) and U-PPO 2000 (right) OIH matrices, non-irradiate, before (black) and after (red) the ammoniac chemical treatment of the hybrid thin film (50 μm). The same results were obtained for the U-PPO 230 and U-PPO 4000 OIH matrices -Annex. 3.6 (a) SAXS1 beamline at LNLS synchrotron ring -Campinas, Brazil (b) apparatus containing liquid nitrogen for the heating/cooling procedure and (c) a constant flux of air to avoid water crystallization at the sample holder surface 3.7 Typical SAXS curve of the U-PEO 1900 OIH matrix (black) and its Porod function (see equation inserted in the figure) fitting (red).

6. 26 1

 261 Nyquist Impedance diagrams of the U-0.8 PPO 2000 :Li + :U-0.2 PEO 1900 :Li + monolith at various temperatures 6.27 Nyquist Impedance diagrams of the U-PPO 2000 :Li + monolith at various temperatures 6.28 (a) U-PEO 1900 :Li + adjustment of the Nyquist diagram at -10 °C using a RQ -RQ -RQ equivalent circuit model, (b) Nyquist diagram at + 80°C and (c) Schematization of the EEC model used for describing the U-PEO 1900 :Li + electrical response: The blue parallel circuit represents the bulk electrical resistance, ascribed to the PEO 1900 semi-crystalline fraction at the helical conformation. The green parallel connection stands for the influence of PEO 1900 in the fully amorphous zone. The red parallel circuit represents the anode's charge transfer 6.29 U-PPO 2000 :Li + (Left) adjustment of the Nyquist diagram at -10 °C using a RQ -RQ model and (Right) Nyquist diagram at + 80°C 6.30 Temperature-dependent conductivities of (a) U-PEO 1900 :Li + , (b), (c) and (d) for Ux PPO 2000 :Li + :U-1-x PEO 1900 blending with χ PEO 1900 x = 0.8, 0.5 and 0.2, respectively and (e) U-PPO 2000 :Li + . 6.31 Isothermic evolution of the specific conductivity (σ s ) Ux PPO 2000 :Li + :U-1- x PEO 1900 :Li + hybrid blend with different PPO 2000 content (a) -90 to -50 °C (b) -0 to 0 °C (c) 10 to 50 °C and (d) +60 to +100 °C. Different polymers and their respectively value of ionic conductivity at room temperature 5 3.1

 2 . 4 . 1 19  2 . 4 . 2 23  2 . 4 . 3 23  2 . 4 . 4 26  2 . 5 . 1 28  2 . 5 . 3 29  2 . 5 . 4 32  2 . 5 . 6 34  2 . 5 . 7 41 3. 2

 2411924223243232442625128253292543225634257412 Ionic conductors; ...........................................................................................................Lithium-ion battery; ......................................................................................................Effect of the plasticizers in conductivity; ......................................................................Others parameters affecting the ionic conductivity; ......................................................24 2.5 Optical Properties: ..................................................................................................................Luminescence; ...............................................................................................................26  2.5.2 Europium (III); ..............................................................................................................Luminescence mechanism of Ln 3+ ions and selection rules; .........................................Lanthanide containing OIH materials; ..........................................................................30  2.5.5 Antenna Effect; .............................................................................................................Hypersensitivity; ...........................................................................................................Lanthanide containing OIH and photo-ageing; .............................................................35 2.6 Sol-gel method: ............................................................................................................................37 Chapter 3: ...............................................................................................................................................40 Methodology ..........................................................................................................................................40 3.1 Synthesis: .....................................................................................................................................Materials and methods: ................................................................................................................43  3.2.1 U-PPO n films; ................................................................................................................43  3.2.2 Differential Scanning Calorimetry (DSC); ....................................................................44  3.3.3 Raman spectroscopy with temperature-controlled program; ........................................44

[

  photoproducts. This study was carried out by FTIR spectral signature and luminescence

  Analysis of the Eu 3+ -loading effect in the OIH matrix structure by: o Differential Scanning Calorimetry (DSC). o Room temperature Infrared spectroscopy (FTIR). o In situ Raman spectroscopy data collection during programed temperature change. o Room temperature Small Angle X-Ray Scattering (SAXS) data collection during programed temperature change.  Time effect of the UV-vis light irradiation (λ>300nm), corresponding to mild conditions of accelerated aging, on the structure of the OIH: o Room temperature Infrared spectroscopy (FTIR).  Evaluation of the photo-degradation kinetics and OIH photo-products: o Ammoniac chemical treatment. o Room temperature Infrared spectroscopy (FTIR).

Figure 2 . 1 :

 21 Figure 2.1: Griffon: Hybrid creature from Greek mythology 24 .

  . A schematic diagram of OIH materials in classes I and II are shown in Fig. 2.2.

Figure 2 . 2 :

 22 Figure 2.2: Schematic representation of class I (a) and class II (b) OIH materials Adapted from 37 .

Figure 2 . 3 :

 23 Figure 2.3: Transparent Siloxane-Poly(ether) hybrid materials, based on PEO and PPO polymers. The magnification of the crosslinking nodes exemplifies the Si-O-Si crosslinking structure network of the matrix Adapted from 40 .

Figure 2 . 4 :

 24 Figure 2.4: Dependency of the Volume with the Temperature for a crystalline (curve 1) and noncrystalline material (curve 2) Adapted from 48 .

Figure 2 . 5 :

 25 Figure 2.5: Schematic representation of a DSC pattern of a generic semi-crystalline polymer, representing the glass transition (T g ) and the melting point (T m ) 54 .

Figure 2 . 6 :

 26 Figure 2.6: Microlithographic trends in minimum device feature size and imaging technology. The figure illustrates the time evolution of random access memory (RAM) devices 60 . Meaning of acronyms at Glossary.

Figure 2 . 7 :

 27 Figure 2.7: Examples of the future manufacturing of electronic devices utilizing OIH materials Compilation from 65,66,67,68 . The most known solid polymeric electrolyte is the poly(ethylene oxide)/LiClO 4 system 51 , with a lithium salt defined by the ratio [O]/[Li] = 8, where "O" is the polar

Figure 2 . 8 :

 28 Figure 2.8: Chemical formula of monomers constituting PEO and PPO polymers [ elaborated by the author ].

Figure 2 . 9 :

 29 Figure 2.9: (a) Ionic transport interrupted by the active charger transfer saturation and (b) Dependency of the ionic conductivity with the charge transfer (n) concentration [ elaborated by the author ].

  2.10 (a)). The rise in temperature promotes the glass → rubbery → liquid-like transition, accompanied by the increase of the polymeric free volume, which facilitates the Li + migration through the ether-type oxygens from organic chains. This behavior is induced by an increase in solid state diffusion in the poly-electrolyte as well as a decrease in charge transfer resistance between electrode and electrolyte (Fig.2.10 (b)).

Figure 2 . 10 :

 210 Figure 2.10: Schematization of the Li + ionic transfer mechanism (a) in the glass state (T < T g ) and (b) in the rubbery state (T > T g ) [ elaborated by the author ].

Figure 2 . 11 :

 211 Figure 2.11: Examples of natural light emitted by glow worms, Aurora Borealis, rotting fish and luminescent wood [ Compilation from[START_REF] White | The glow worms adaptations[END_REF][START_REF]THE 10 BEST places to stare in awe at the aurora borealis[END_REF][START_REF]EXPLORE peixe de água salgada e muito mais! Pinterest[END_REF][START_REF] Workshop | Make a log slice wood art décor -woodworking[END_REF] ].

Figure 2 . 12 :

 212 Figure 2.12: Luminescence spectrum [Eu(tta)3(phen)] at 77 K upon excitation at 396 nm. All of the transitions start from the 5 D 0 state 104 .

Figure 2 . 13 :

 213 Figure 2.13: Schematic representation of the Eu 3+ :OIH complex derived from functionalized dipicolinic acid ligands 141 .

Figure 2 .

 2 Figure 2.14: (a) U-PPO 2000 OIH matrix (blue emission) and U-PPO 2000 OIH:Eu 3+ complex (red emission) developed at this thesis and (b) CIE chromaticity diagram of a generic support matrix, doped with different Ln 3+ , showing the photoluminescence dependency of the lanthanide cation [ elaborated by the author ].

Figure 2 . 15 :

 215 Figure 2.15: Schematic diagram of the Antenna Effect by the organic ligand with an efficient energy transfer to the lanthanide center [ elaborated by the author ]. 2.5.6 Hypersensitivity; One of the most interesting phenomena found in the Eu 3+ emission diagram is the "hypersensitive" 5 D 0 → 7 F 2 transition 145,146 . The intensities of most induced ED

 2 . 5 . 7

 257 described that the 5 D 0 → 7 F 2 transition intensity of Eu 3+ complexes is about 100 times more intense compared to a water solution in contact with the rare earth ions 147 . The observed hypersensitive intensity electric dipole 5 D 0 → 7 F 2 transition enhancement is due to the low local symmetry of the Eu 3+ , relaxing the forbidden Laporte rules, which is well accepted by literature148,149,150 . Lanthanide containing OIH and photo-ageing;While there are hundreds of publications about polymer photo-ageing, this kind of study for OIH materials does not yet have the same attention. Scopus data base has

Figure 2 . 16 :

 216 Figure 2.16: Acid (a) and Basic (b) catalysis reaction mechanism to the siliceous alkoxide 171 .

Figure 3 . 1 :

 31 Figure 3.1: Schematic diagram of the different OIH -matrices with their two polar oxygen active sities, I: O ether and II: O carbonyl , respectively adapted from 35 .

Figure 3 . 2 :

 32 Figure 3.2: Schematic representation of the synthesis of the U-PEO 1900 and U-PPO n OIH, Metalunloaded, Li + -loaded and Eu 3+ -loaded OIH materials. An analogous process was adopted in the synthesis of the OIH materials from POs 230, 2000 and 4000 (n = 2.3 and 68, respectively) Adapted from 177 .

Figure 3 . 3 :

 33 Figure 3.3: DSC time and temperature-control program elaborated by the author .

 3 . 3 . 4

 334 Artificial Accelerated Photo-Oxidation;UV-light irradiations were carried out in a SEPAP 12/24 unit. This apparatus has been designed for the study of polymer photo-degradation in artificial aging corresponding to medium accelerated conditions 178 . The chamber is an elliptical reactor equipped with one medium-pressure mercury lamp (Mazda MA 400) in the vertical position at one axis of the chamber. Wavelengths below 300 nm are filtered by a glass envelope. At the second axis of the chamber, the samples were fixed on a rotating carousel with a 13 cm diameter which can receive 24 samples (Figure 3.4 (a)). The samples (cylindrical OIH monoliths and OIH films) were fixed in the hollow-centered metallic sample holder. A schematization is shown in Figure 3.4 (b). In this series of experiments, the temperature at the surface of the samples was fixed at 60 ºC

Figure 3 . 4 :

 34 Figure 3.4: (a) Photograph of the SEPAP 12/24 chamber during activity and (b) metallic sample holder with a hollow center elaborated by the author .

  3.5). NH 3(g) treatments were carried out in purely Teflon systems. This procedure was well known in the Laboratoire de Photochimie Moléculaire et Macromoléculaire -Université Clermont Auvergne, AUBIERE, France 179 and was used for photo-oxidation of U-PPO n Eu 3+ -unloaded and Eu 3+ -loaded OIH materials by UV-light irradiation (λ > 300 nm).

Figure 3 . 3 . 3 . 6

 3336 Figure 3.5: U-PEO 1900 (left) and U-PPO 2000 (right) OIH matrices, non-irradiate, before (black) and after (red) the ammoniac chemical treatment of the hybrid thin film (50 μm). The same results were obtained for the U-PPO 230 and U-PPO 4000 OIH matrices -Annex II elaborated by the author .

  The parasitic scattering intensity (due to the cell windows and vacuum) was subtracted from the total scattering intensity. Small pieces of the monolithic hybrids were introduced into thermostated, coupled sample cells and the measurements were performed from -100 °C to + 100 °C, at 5 °C/min. System cooling and heating was carried out by liquid nitrogen using a furnace type Transmission, Capilar and Mica, model DSC6000, allowing for work to be done in a temperature range from -196 °C to 600 °C for solid and liquid samples, manufactured by Linkan 180 . SAXS patterns were recorded every 12 sec during heating, taking one measurement at each degree (°C). To avoid water crystallization on the glass surface of the sample holder, a constant flux of air was injected in the sample holder surface during the cooling procedure Fig.3.6 (c).

Figure 3 . 6 :

 36 Figure 3.6: (a) SAXS1 beamline at LNLS synchrotron ring -Campinas, Brazil (b) apparatus containing liquid nitrogen for the heating/cooling procedure and (c) a constant flux of air to avoid water crystallization at the sample holder surface elaborated by the author .

Figure 3 . 7 :

 37 Figure 3.7: Typical SAXS curve of the U-PEO 1900 OIH matrix (black) and its Porod function (see equations inserted in the figure) fitting (red) elaborated by the author .

Figure 3 . 8 :

 38 Figure 3.8: Subtraction of power law contribution from the U-PEO 1900 SAXS curve. The insert show a schematic representation of the siloxane nodes distance spaced by the polymeric chain elaborated by the author .

Figure 3 .

 3 Figure 3.9: (Left) Gaussian equation and (Right) Gaussian function elaborated by the author .

 3 . 3 . 8

 338 Fig. 3.10) by a Leit-C ® (sigma-aldrich # 09929)

 4 . 2 . 1

 421 Thermal behavior;DSC curves (Fig.4.1), for all OIH materials showed that there was a relatively sharp change of the heat capacity (ΔC p ), characteristic of the glass transition. The T g event occurred at -58 and -60 C for U-PEO 1900 and U-PPO 2000 , respectively. The Eu 3+loading did not show changes in the T g value, suggesting that the Eu 3+ -OIH matrix coordination does not happen in the (-C-O-C-) backbone. The DSC curves also revealed an endothermic fusion peak for the U-PEO 1900 and U-PEO 1900 :Eu 3+ ascribed to the crystalline PEO 1900 melting temperature (T m ~25 °C) which is absent in the case of the PPO 2000 OIH matrix. The presence of the endothermic fusion peak for U-PEO 1900 :Eu 3+ is an important indicator that Eu 3+ cations do not break the helical conformation, typically found in semi-crystalline polymers 182 , thus supporting the coordination between the lanthanide and OIH matrix by another active site. The investigation of Eu 3+ coordination was carried out by spectroscopy techniques.

Figure 4 . 1 :

 41 Figure 4.1: DSC curves of U-PEO 1900 and U-PPO 2000 Eu 3+ -unloaded (black) and Eu 3+ -loaded (red).

 4 . 2 . 2

 422 Room temperature FT-IR analysis of the OIH:Eu 3+ complexes;One way to study the structural modifications caused by adding an inorganic salt to OIH matrices is by IR spectra analysis on the region of the C-O-C backbone stretching (νCOC) mode, 1200-1000 cm -1 (Fig 4.2). The C-O-C backbone region is sensitive to changes occurring in the conformations of the polyether chains as result of the bonding between the guest cation and the polar oxygen ether-type atoms present in the polyether 183 . Figs 4.2 (a) and (b) do not show significant changes in the IR spectra of the OIH materials after Eu 3+ -loading. In the νCOC region spectra, all studied OIH matrices (unloaded and Eu 3+ -loaded U-PEO 1900 U-PPO 2000 and U-PPO 4000 ) show a broad band centered around 1110 cm -1 and a shoulder at 1150 cm -1 . These events, ascribed to the νCOC vibration mode and to the coupled vibration of the νCOC and rCH 2 modes, respectively, indicate the presence of the C-O-C backbone non-coordinated with the

Figure 4 . 2 :

 42 Figure 4.2: FTIR spectrum of (a) U-PEO 1900 and U-PEO 1900 Eu 3+ and (b) U-PPOs with different molecular weight (wt = 230, 2000 and 4000 g.mol -1 ) Eu 3+ -unloaded OIH materials (solid line) and OIH:Eu 3+ complexes (dotted line), films (50 μm) in the ν(C-O-C) backbone (1200 -950 cm -1 ) region.

  1640 cm -1 ) is a highly complex vibration 186 that involves the contribution of C=O stretching, which is sensitive to the specificity and magnitude of hydrogen bonding. Thus, the amide I vibration consists of several components reflecting C=O groups in different environments 187 . The Amide II region (around 1545 cm -1 ) is mainly associated with the N-H in-plane bending vibration 188 , which is sensitive to the chain conformation and intermolecular hydrogen bonding205 . The coordination between Eu 3+ ions and carbonyl oxygen atoms from urea linkages have been intensely investigated and so far, well accepted by other researchers 185 . Carlos et al have reported modifications in the spectra at the Amide I region due to the presence of a lanthanide salt in ureasil in OIH materials 189 . The authors have shown that the polyether chains are not strongly involved in the solvation of the Ln 3+ cations, and the presence of new components in the urea spectral region suggest that the Eu 3+ cations are preferentially coordinated by the carbonyl oxygens.

Fig 4 . 3 Figure 4 . 3 :

 4343 Fig 4.3 presents the spectra for OIH materials (solid line) and OIH:Eu 3+ complexes

Fig 4 . 4

 44 (b) shows the Gaussian fitting of the amide region spectra, and the best adjustment was obtained by the convolution of three components at 1642, 1660 and 1680 cm -1 , for the Amide I region. These distinct components are attributed to ordered hydrogen bonding urea/urea, urea/poly(ether), disordered hydrogen bonding urea/poly(ether), poly(ether)/ poly(ether) and "free" C=O environment, respectively 192 .

Figure 4 . 4 :

 44 Figure 4.4: FTIR spectra in the amide region with the 2 nd curve derivate for (a) U-PEO 1900 and (c) U-PEO 1900 :Eu 3+ and the Gaussian fitting of the amide region for (b) U-PEO 1900 and (d) U-PEO 1900 :Eu 3+ . The second derivate of the U-PEO 1900 :Eu 3+ curves Fig 4.4 (c) reveals a feature

Figure 4 . 5 :

 45 Figure 4.5: Schematization of the Eu 3+ coordination with the OIH matrix.

  CH 2 195 . It is well known that this energy range is sensitive to modifications of the PE ν S (C-O-C) backbone conformations by intermolecular interactions and/or temperature196 . In order to describe the changes of polymer conformation, it is convenient to use the conformer ratio of gauche and trans arrangements along the polymer backbone. The gauche/trans conformation correlation can be performed by the analyses in FT-Raman as a function of the temperature in the CH 2 backbone fingerprint spectral region and the effect of Eu 3+ -loading in the OIH matrix.

Fig 4 . 6

 46 Fig 4.6 shows the temperature dependency of the FT-Raman for U-PEO 1900 (a) Eu 3+ -unloaded and (b) Eu 3+ -loaded. In regards to the intermolecular interactions of OIH

Fig. 4 .

 4 6 (a), it is observed that when the temperature increases up to the PEO 1900 T m (~ 25 °C), the well-defined bands at 844, 1063, 1144, 1234 and 1278 cm -1 vanish, giving rise to a set of broad bands accompanied by a displacement of the maximum bands to lower values of energy, leading to the increase of the trans/gauche conformer ratio of the chains 202 . The appearance of the broad bands is due to the change of the helical conformation, typical of the crystalline PEO 1900 , to an amorphous trans -like conformation for the PE ν S (C-O-C) backbone 203 .Thus the local degree of order of the chains increases, meaning that the population of gauche conformers increases as well. FT-Raman of U-PPO 2000 , Fig. 4.7, shows a trans ν S (C-O-C) conformational backbone,

Figure 4 . 6 :

 46 Figure 4.6: Raman Spectroscopy in situ with the temperature, from -100 °C to 100 °C, in an energy range from 800 to 1300 cm -1 for a U-PEO 1900 OIH material (a) Eu 3+ -unloaded and (b) Eu 3+ -loaded.

Fig. 4 .Figure 4 . 7 :

 447 Fig. 4.7 (a) and (b) shows the Raman spectra measured in situ with the heating of U-PPO 2000 and U-PPO 2000 :Eu 3+ , respectively. The Raman spectra for the Eu 3+ -loaded

Figure 4 . 8 :Figure 4 . 9 :

 4849 Figure 4.8: Room temperature SAXS curves for the (top) U-PPO 2000 (black) and U-PPO 2000 :Eu 3+ (red) and (botton) U-PEO 1900 (black) and U-PEO 1900 :Eu 3+ (red) OIH materials

Figure 4 . 10 :

 410 Figure 4.10: Effect of UV-light exposure times on the emission spectra of the Eu 3+ -OIH complex, (a) U-PEO 1900 and (b) U-PPO 2000 .

Fig. 4 .

 4 photoluminescence quantum yield (PL-QY). Absolute QY values in different times of

Fig. 4 .

 4 Fig. 4.11 (b) shows a maximum displacement from 340 nm (black) to 368 nm (red)

Figure 4 . 11 :

 411 Figure 4.11: Excitation spectra, in the spectral range from 250 to 500 nm, of the OIH:Eu 3+ complexes, (a) U-PEO 1900 and (b) U-PPO 2000 , exposed to different UV-irradiation times.

  5.1). This process occurs on a secondary carbon in the β-position from an ether-type 224 oxygen, and was well defined by J-L Gardette and S. Therias 225 . The molecular structure of hydroperoxides produced from photo-aging of U-PPO OIH materials can result in three different photoproducts (Fig.5.2). The different possibilities of the photo-products for U-PPO hydroperoxide are consequences of ageing, which produces heterogeneous effects mostly caused at a macroscopic level due to the oxygen diffusion-limited effects226 . These heterogeneous effects are dependent on the coupling of chain with the oxygen consumption rate, which depends on the reactivity of the polymer and the oxygen permeability in the material 227 .

Figure 5 . 1 : 3

 513 Figure 5.1: Mechanism of photo-degradation of U-PPO in hydro-peroxide and macro-radical.

Figure 5 . 3 :

 53 Figure 5.3: FTIR spectra evolution during accelerated photo-aging assays (a) U-PPO 2000 and (b) U-PPO 2000 :Eu 3+ films (50 μm) in different UV-light exposure at λ ≥ 300 nm and 60 ºC.

Figure 5 .

 5 Figure 5.4 displays the time evolution of the area of the band at 1720 cm -1 for the U-PPO prepared with PPO of different molecular weights. From Fig.5.4 (a), at 1720 cm -1 , a remarkable variation in curves profiles with the Eu 3+-loading and with PPO molecular

Figure 5 . 5 :

 55 Figure 5.5: Variation of absorbance at 1608 cm -1 as a function of UV irradiation time (photooxidation at λ > 300 nm, 60 ºC) for Eu 3+ -loaded U-PPO films with different molecular weights (2000 and 4000 g.mol -1 ).

Figure 5 . 6 :

 56 Figure 5.6: Effect of NH 3 treatment of (a) U-PPO 2000 and (b) U-PPO 2000 :Eu 3+ , films photo-degraded by 10 h of UV-light exposure (λ ≥ 300 nm, 60 ºC), in IRFT spectra in the carbonyl range.

Figure 5 . 7 :

 57 Figure 5.7: Schematic diagram of the reactions between ammonia with U-PPO 2000 photoproducts.ν(C=O) 1750cm-1

Figure 5 . 8 :

 58 Figure 5.8: Schematization of the application of U-PPO n :Eu 3+ complexes as optical marker showing the red → blue transition.

Figure 5 . 9 :

 59 Figure 5.9: Evolution of the U-PPOs:Eu 3+ QY-value as a function of the long wavelength (λ > 300 nm) UV-light irradiation.

Fig. 6 .Figure 6 . 1 :

 661 Fig. 6.1 (a) shows the DSC trace of PEO 1900 , PPO 2000, U-0.5 PPO 2000 :U-0.5 PEO 1900 blend and Li + loading samples, measured during heating from -90 °C to + 200

Figure 6 . 2 :

 62 Figure 6.2: Dependence of the glass transition temperature on the percentage of PPO 2000 at the Ux PPO 2000 :U-1-x PEO 1900 hybrid blend, respectively.

Fig. 6 .Figure 6 . 3 :Figs. 6 .

 6636 Fig. 6.3 reveals that the D C follows the dashed, straight line corresponding to a

Figure 6 . 4 :

 64 Figure 6.4: Room temperature FTIR pattern, in the spectral range from 1800-1100 cm -1 , Li + -unloaded (black) and Li + -loaded (blue) for thin films (50 μm) of (a) U-PEO 1900 and (b) U-PPO 2000.

Fig 6 . 5

 65 Fig 6.5 (c) shows the second derivate of the U-PEO 1900 :Li + -loading OIH matrix and

Figure 6 . 5 :

 65 Figure 6.5: FTIR spectra in the amide region with the 2 nd curve derivate for (a) U-PEO 1900 and (c) U-PEO 1900 :Li + and the Gaussian fitting of the amide region for (b) U-PEO 1900 and (d) U-PEO 1900 :Li + .

Figure 6 . 6 :Fig. 6 .

 666 Figure 6.6: Comparison between the relative area of Amide I and of U-PEO 1900 (black) and U-PEO 1900 :Li + (blue). 6.3.2 In situ with the temperature FT-Raman Spectroscopy;

Figure 6 . 7 :

 67 Figure 6.7: Raman spectra of (a) Li + -unloaded and (b) Li + -loaded U-PEO 1900 as a function of the temperature from -85 to 100 °C.On the other hand,the structural backbone conformation characterized by the set of bands in the 836 -869 cm -1 region remains almost invariant in the range of all temperatures. These results allowed us to conclude that U-PEO 1900 -Li + complexing

Fig. 6 .

 6 Fig. 6.8shows the Raman spectra of Li + -unloaded and Li + -loaded U-PPO 2000 as a

Figure 6 . 8 :

 68 Figure 6.8: Raman spectra of (a) Li + -unloaded and (b) Li + -loaded U-PPO 2000 as a function of the temperature from -85 to 100 °C.

Figure 6 . 9 :

 69 Figure 6.9: Room temperature log-log SAXS curves of Ux PPO 2000 :U-1-x PEO 1900 blends prepared with different PPO 2000 fraction, (a) Li + -unloaded and (b) Li + -loaded.

  point of PEO 1900 (T m = 25 °C) confirm the attribution of this peak to the periodicity of the superstructure formed by the semi-crystalline PEO 1900 phase. Moreover, this feature is in full agreement with the temperature dependence of PEO 1900 organic chain conformation revealed from Raman spectra (Fig.6.7 (a)), in which a transition from a gauche state to trans state is found at the same temperature range where the disappearance of the middle q-range maximum was observed. This phenomenon leads us to conclude that the long-distance period peak found for U-PEO 1900 above T m also has a backbone conformation dependence 239 . On the other hand, all OIH materials have shown increases of the correlation peak intensity during heating. This feature is due to the increase of the electron density contrast difference associated with the thermal expansion of the polymeric framework as shown by the displacement of the siloxane correlation peak position during heating (Fig 6.12 (a) and (b)).

Figure 6 . 10 :

 610 Figure 6.10: Tri-dimensional log-log SAXS curves measured in situ during a temperature range increasing from -100 °C to 100 °C, and their calorimetric curve (a) U-PEO 1900 and (b) U-PEO 1900 :Li + .

Figure 6 .

 6 Figure 6.11: Tri-dimensional log-log SAXS curves measured in situ during a temperature range increasing from -100 °C to 100 °C, and the their calorimetric curve (a) U-PPO 2000 and (b) U-PPO 2000 :Li + .

Figure 6 . 12 :

 612 Figure 6.12: Average displacement of the siloxane correlation peak position (ξ) as a function of temperature for (a) U-PEO 1900 (black) and U-PPO 2000 (blue), unloaded (full circles) and Li + -loaded (empty circles).

Figure 6 .

 6 Figure 6.13Corrected SAXS curves of (a) U-PEO 1900 long period semi-crystalline peak and ξ SC peak position as a function of temperature and siloxane correlation peak of (b) U-PEO 1900 and (c) U-PEO 1900 :Li + .The Gaussian fitting for U-PEO 1900 , Fig.6.14, reveals a peak profile composed of

Figure 6 . 14 :Figure 6 . 15 :Fig 6 .

 6146156 Figure 6.14: Gaussian fitting of the siloxane correlation peak: (a), (b) and (c) for U-PEO 1900 and (d), (e) and (f) for U-PEO 1900 :Li + , at -100, +5 and +100 °C. The fitting was made utilizing three component named here as components #1 (red) #2 (black) and #3 (blue).

Figure 6 . 16 :

 616 Figure 6.16: Evolution of the average distance (ξ) of three Gaussian components of the correlation peak of (a) U-PEO 1900 and (b) U-PEO 1900 :Li + .

Fig. 6 .

 6 Fig.6.17(a) shows the evolution of area with temperature for each component of

Figure 6 .Figure 6 . 18 :

 6618 Figure 6.17: (a) Evolution of the three different component areas (x10 -4 nm 2 ) and the middle-q area (nm 2 ) as a function of the temperature from -100 °C to 100 °C.

  8 U-PPO 2000 confirms the complete solubilization of semi-crystalline PEO 1900 in amorphous U-PPO 2000 matrices, as suggested by the DSC results. After the Li + incoporation in the1

Fig 6 .

 6 Fig 6.19(a) and (b) displays the temperature dependency of the average correlation

Figure 6 . 19 :

 619 Figure 6.19: Average displacement of the siloxane correlation peak position (ξ) as a function of temperature for (a) U-PEO 1900 (black), U-0.2 PPO 2000 /U-0.8 PEO 1900 (green) U-0.5 PPO 2000 /U-0.5 PEO 1900 (red), U-0.8 PPO 2000 /U-0.2 PEO 1900 (magenta) and U-PPO 2000 (blue) (a) unloaded and (b) Li + -loaded.

  SAXS curves of Ux PPO 2000 :U-1-x PEO 1900 corrected using equation 10 are displayed in Fig. 6.20. This correction makes the absence of maxima associated with semi-crystalline domains of PEO 1900 in the unloaded (Fig 6.20(a)) and Li + -loaded (Fig 6.20 (b)) blend prepared with the higher amount of PPO 2000 (0.8) evident. The two well defined maxima associated with semi-crystalline domains of PEO 1900 and with the correlation peak of siloxane nodes are evident in the Li + -unloaded blend with x = 0.5 and 0.2 of U-PPO 2000 (Fig.

Figure 6 . 20 :

 620 Figure 6.20: Straight line equation SAXS curves subtraction at siloxane correlation peak as a function of the temperature for Ux PPO 2000 :U-1-x PEO 1900 OIH blends for a x PPO 2000 fraction equal to (a) 0.8unloaded, (b) 0.8 -Li + -loaded, (c) 0.5 -unloaded, (d) 0.5 -Li + -loaded, (e) 0.2 -unloaded and (f) 0.2 -Li +loaded.

  (a)), where component # 3 remains almost constant in the entire range of temperatures. This behavior can be due to the hydrophobic contribution from PPO 2000 present in the blend. On the other hand, the maxima ascribed to the long period distance (middle q-range -magenta) display transient contribution between 0 and 15 o C, which can result from PEO 1900 cold crystallization. The vanishing of this peak occurs at the same temperature which the area of components # 2 and 3 start to increase. We also observe in this temperature range an acceleration of the siloxane correlation distance increasing for components #1 and # 2 (Fig.6.21 (b)). These findings indicate the presence of water in the PEO 1900 lamellae crystallite organization, hydrogen bonded with polar ether-type oxygens present in the polymer chains. Moreover, we again observe that the ratio between the correlation distance ξ #1 /ξ #2 stays almost temperature invariant and the average value (ξ #1 /ξ #2 = 1.3± 0.05) became lower than the expected for the cubic packing of the siloxane node Figs.6.21(a).

Figure 6 .Fig. 6 .

 66 Figure 6.21: (a) Evolution of the three different component areas (x10 -4 nm 2 ) and the middle-q area (nm 2 ) and (b) evolution of the average distance (ξ) relative to the three different components from the Gaussian fitting of the correlation peak for U-0.5 PPO 2000 /U-0.5 PEO 1900 OIH blend.

Figure 6 . 5

 65 Figure 6.22: (a) Evolution of the three different component areas (x10 -4 nm 2 ) and the middle-q area (nm 2 ) and (b) evolution of the average distance (ξ) relative to the three different components from the Gaussian fitting of the correlation peak for U-0.2 PPO 2000 /U-0.8 PEO 1900 OIH blend.

PPO 2000 :Figure 6 . 23 :Figure 6 . 24 :Figure 6 . 25 :Figure 6 . 26 :Figure 6 . 27 :

 2000623624625626627 Figure 6.23: Nyquist Impedance diagrams of the U-PEO 1900 :Li + monolith at various temperatures.

  circuit represents bulk electrical resistance, ascribed to the relaxation time of PEO 1900 at the helical (gauche) conformation associated with the memory of the semi-crystalline state. The segmental relaxation process has an important role in controlling ion transport in these solid polymer electrolytes 247 . The completely glass structure is found in this range of temperatures, which could have a relaxation time near the PEO 1900 crystal.With the increase in temperature, the relaxation time at the high frequency arises from the motion of the polymer chains due to the glass → rubber transition. Temperature has the effect of decreasing relaxation times 248 , consistent with the increase of ionic conductivity. On the other hand, the amorphous layer fraction present between the crystalline lamellae of the long period PEO 1900 superstructure must have a different relaxation time, ascribed to the second parallel circuit in the middle frequency region from 5 kHz to 50 Hz. The third parallel circuit in lower-frequency ranges represents the charge transfer at the anode interface 249 . The relaxation in the low frequency region is the electrode polarization phenomenon occurring as a result of an accumulation of ions near the electrodes 247 . Fig. 6.28 (c) shows a schematic diagram of the (-RQ -RQ -RQ -) model used, indicating where the different processes take place. U-PPO 2000 :Li + (Figs 6.29) and Ux PEO 1900 :Li + / 1-x PPO 2000 :Li + OIH blends (Annex)show the Nyquist impedance diagrams that are in agreement with the well-known RQ -RQ model (inserted inFigs 6.28 and 6.29). In this kind of model, the first parallel circuit represents bulk electrical contribution of the hybrid electrolyte and the second parallel circuit represents the low-frequency charge transfer at the anode interface. It is well accepted that PPO 2000 is an amorphous polymer, making the ECC composed of two parallel associations -RQ -RQ -physically consistent with the experimental results and with the nano-structural feature of OIH:Li + . This ECC is physically consistent with the mechanism of ionic transfer, in which the ions hoop through the amorphous fraction of PEO 1900 and PPO 2000 polymers and not by the PEO 1900 semi-crystalline region.

Figure 6 .

 6 Figure 6.28: (a) U-PEO 1900 :Li + adjustment of the Nyquist diagram at -10 °C using a RQ -RQ -RQ equivalent circuit model, (b) Nyquist diagram at + 80°C and (c) Schematization of the EEC model used for describing the U-PEO 1900 :Li + electrical response: The blue parallel circuit represents the bulk electrical resistance, ascribed to the PEO 1900 semi-crystalline fraction at the helical conformation. The green parallel connection stands for the influence of PEO 1900 in the fully amorphous zone. The red parallel circuit represents the anode's charge transfer.

Figure 6 .

 6 Figure 6.29: U-PPO 2000 :Li + (Left) adjustment of the Nyquist diagram at -10 °C using a RQ -RQ model and (Right) Nyquist diagram at + 80°C.

Fig. 6 .

 6 Fig. 6.30 analyzes the dependence of the specific ionic conductivity of OIH:Li +

Figure 6 . 30 :

 630 Figure 6.30: Temperature-dependent conductivities of (a) U-PEO 1900 :Li + , (b), (c) and (d) for Ux PPO 2000 :Li + :U-1- x PEO blending with PEO 1900 fraction x = 0.8, 0.5 and 0.2, respectively and (e) U-PPO 2000 :Li + .

Figure 6 . 31 :

 631 Figure 6.31: Isothermic evolution of the specific conductivity (σ s ) Ux PPO 2000 :Li + :U-1-x PEO 1900 :Li + hybrid blend with different PPO 2000 fraction (a) -90 to -50 °C (b) -0 to 0 °C (c) 10 to 50 °C and (d) +60 to +100 °C.

8 and 1 U

 1 -PEO 1900 :Li + showed a ECC model as RQ -RQ -RQ, ascribed to the PEO 1900 helical conformation, amorphous conformation and electrode charge transfer, respectively, U-PPO 2000 :Li + and the OIH blends showed a RQ -RQ model, suppressing the PEO 1900 helical conformation contribution. At T > PEO 1900 T m , the solids OIH:Li + monoliths behaves as ionic liquids, and the RQ -RQ model is no longer anymore satisfactory to fit the Nyquist impedance patterns. The temperature-dependence conductivities of the OIH:Li + monoliths obey Arrhenius rule. The observed Arrhenius behavior in the blend is attributed to the lower mobility of PEO 1900 segments in amorphous phase, which are restrained between crystalline regions, and the poor ionic mobility of PPO 2000 . The enhancement of ionic conductivity with the increase of temperature (T > 50 °C) is attributed to the fully amorphous structure. Sol-gel methods allowed for the synthesis of rubber, transparent, flexible and moldable OIH materials with different optical and ionic conductivity properties caused by the addition of Eu 3+ and Li + , respectively. From several spectroscopy techniques, we were able to prove that Eu 3+ and Li + are coordinated by different polar sites of the OIH matrices, with the former interacting with the oxygen carbonyls of the urea linkage and the latter being solvated by ether type oxygens of the polyether. The Eu 3+ dissociation into the matrix was confirmed by the narrow emission lines, ascribed to the 5 D 0 → 7 F j europium transition. The Eu 3+ ---O carbonyl coordination leaves the PEO 1900 tgt helical conformation (O-CH 2 -CH 2 -O backbone chains) untouched, while the coexistent, amorphous and semi-crystalline phase led to the poor PL-QY values for this OIH:Eu 3+ matrix, as compared to amorphous U-PPO 2000 :Eu 3+ material. Independent from the confirmation of Eu 3+ -O carbonyl coordination from urea groups, we obtained the continuous recovery of the Amide I structure during Eu 3+ decomplexation induced by exposure to intense UV-light. Formate and ester were considered the main photoproducts formed by UV-light exposition, which were confirmed by the ammoniac chemical treatment of photo-degraded OIH materials. The visible red → blue PL transition observed with the increase of UV-light exposure for OIH:Eu 3+ materials based on PPO 2000 and PPO 4000

Figure A. 1 :Figure A. 3 :

 13 Figure A.1: Effect of UV-light exposure times on the emission spectra of the Eu 3+ -OIH complex, (left) U-PPO 230 and (right) U-PPO 4000 .

Figure A. 4 :

 4 Figure A.4: FTIR spectra evolution during accelerated photo-aging assays (left) U-PPO 4000 and (right) U-PPO 2000 :Eu 3+ films (50 μm) in different UV-light exposure at λ ≥ 300 nm and 60 ºC.

Figure A. 5 :

 5 Figure A.5: NH 3 treatment of (left) U-PPO 230 and (right) U-PPO 230 : Eu 3+ film photo-oxidised at 10 h of UVlight exposure (λ ≥ 300 nm, 60 ºC), in the carbonyl range.

Figure A. 6 :

 6 Figure A.6: NH 3 treatment of (left) U-PPO 4000 and (right) U-PPO 4000 : Eu 3+ film photo-oxidised at 10 h of UV-light exposure (λ ≥ 300 nm, 60 ºC), in the carbonyl range.

  Figure A.7: U-0.2 PPO 2000 :U-0.8 PEO 1900 -Li + -loaded (Left) adjustment of the Nyquist diagram at -10 °C using a RQ -RQ model and (Right) Nyquist diagram at + 80°C.

  Figure A.8: U-0.5 PPO 2000 :U-0.5 PEO 1900 -Li + -loaded (Left) mathematical theoretical adjustment of the Nyquist diagram at -10 °C using a RQ -RQ model and (Right) Nyquist diagram at + 80°C.

  Table content the volume of water (μl) and the mass of europium salt (g), to satisfy the relationship [H 2 O]/[Si]=4 [O carbonyl ]/[Li + ]=15, and [O carbonyl ]/[Eu 3+ ]=3, respectively. Table containing the values of the Gaussian fitting parameters for the Amide I and Amide II regions of the U-PEO 1900 and U-PEO 1900 :Eu 3+ 60 4.2 I( 5 D 0 → 7 F 2 ) / I( 5 D 0 → 7 F 1 ) ratio (Ω 1,2 ), of the Eu 3+ -OIH complex, exposed to different UV-light irradiation times 70 6.1 Attribution of the FTIR spectroscopy bands for the U-PEO 1900 and U-PPO 2000 OIH thin film (50 µm) matrices, Li + -unloaded and Li + -loaded 91 6.2 Table containing the mathematical fitting values of the Amide I and Amide II regions of U-PEO 1900 and U-PEO 1900 :Li + . 93 6.3 Attribution of the Raman bands of Li + -unloaded and Li + -loaded U-PEO 1900 and U-PPO 2000 OIH. 99 6.4 Values of the thermal expansion coefficient represented by the slope of the curve from the average distance of the siloxane correlation peak as a function of the temperature.

	3.2 Volume of water (μl) and the mass of lithium salt (g) used to satisfy the relationship [H 2 O]/[Si]=4 and [O carbonyl ]/[Li + ]=15, and the electrical geometric factor of the U-x PPO 2000 /U 1-x PEO 1900 poly-electrolytes. ΔH f : PEO melting enthalpy ΔH p : Standard melting enthalpy for 100 % crystalline PEO CN: Coordination number DSC: Differential Scanning Calorimetry E a : Energy of activation 4.1 Glossary ED: Electric dipole	42 51
	EEC Eu 3+ :	Electrical Equivalent Circuit Europium trivalent ion
	FTIR:	Fourier Transformer InfraRed
	I(q):

  Chapter 1: .................................................................................................................................................1 Introduction and Objectives .....................................................................................................................1 1.1 Introduction: ...................................................................................................................................2 1.2 General objectives: .........................................................................................................................8 1.3 Specific objectives: ........................................................................................................................8  1.3.1 Europium salt; .................................................................................................................9  1.3.2 Lithium salt; ..................................................................................................................10 Chapter 2: ...............................................................................................................................................11 State of the art ........................................................................................................................................11 2.1 Organic-Inorganic Hybrid Materials: .....................................................................................12

		Temperature of glass transition
	U:	Ureasiloxane
	ULSI:	ultra large scale integration
	U-PEO:	Ureasil -Poly(ethylene oxide) OIH material
	U-PPO:	Ureasil -Poly(propylene oxide) OIH material
	UV:	Ultraviolet
	VLSI:	very large scale integration
	wt:	molecular weight
	3D:	Three-dimensional

xx Summary  2.1.1 Origin, properties and synthesis; ...................................................................................12  2.1.2 Hybrid Siloxane-Poly(ether); ........................................................................................13 2.2 Relationship between Structure/Properties: ...........................................................................15 2.3 Thermal properties: ................................................................................................................15 2.4 Ionic Conductivity Properties: ...............................................................................................19

Table 1 .

 1 1.

Table 1 . 1 :

 11 Different polymers and their respectively value of ionic conductivity at room temperature.

	Polymer	Ionic conductivity S/cm -1	Ref.
	AG/CNT-D400 (6%)	3,39x10 -4	16
	PVDF-HFP/HPMC (4:1)	3,80x10 -4	17
	P(GMA-PEGMA)-D2000(11)	8,29x10 -4	18
	P(NA-GMA)-D2000(23)	8,23x10 -4	19

  PEO 1900 , PPO 2000 and U x PEO 1900 :U-1-x PPO 2000 blends. The thermal features of the OIH matrices were carried out by DSC measurements in a temperature range of -100 °C to 200 °C; these results will be used to examine the structural properties of the OIH matrices. This investigation can be done using FTIR spectroscopy This PhD thesis aims to better understand the optical / electrical properties of the multifunctional OIH materials based on PEO 1900 and PPO n (n = 5, 33 and 68, ascribed to the mw. 230, 2000 and 4000 g.mol -1 , respectively) containing Eu 3+ and Li + , synthesized by the sol-gel method.

	at room temperature and in situ monitoring during programed temperature variation,
	which uses time resolved Raman spectroscopy from -90°C to +100 °C. The nano-
	structural features of these matrices were carried out by SAXS with in situ monitoring
	during programed temperature ranging from -90°C to +100 °C. Impedance

+ -loading on thermal, structural and electrical properties of the OIH matrices based on Spectroscopy was used to analyze the thermal/vibrational/structural/nano-structural results to examine their ionic conductivity properties. This kind of study allowed for the proposition of the Electrical Equivalent Circuit and the relationship between the circuit components and the OIH structural building blocks.

The innovative character of this thesis aims to understand the cause of several external influences on the multifunctional OIH materials properties, as Eu 3+ and/or Li +loading, temperature, photo-ageing and PEO 1900 :PPO 2000 blending. Photo and thermal stability are important structural features, which need to be explored in depth.

Consequently, the objectives of this thesis are given as follows:

1.2 General objectives:

1.1 Origin, properties and synthesis;

  1-x PPO 2000 blending on the relationship of structure vs. ionic conductivity, while focusing on the PPO 2000 plasticization and the structural conformation of PEO 1900 in order to better understand the ionic conductivity of OIH polyelectrolytes. This set of objectives was achieved from an in-depth study of the OIH matrix structures, focused on the effect of the Li + -loading on the thermal, vibrational, structural and nanostructural properties. This set of objectives consists of the following steps:

	2.1 Organic-Inorganic Hybrid Materials:
	 2.
	Chapter 2:
	State of the art

 Analysis of the effects on thermal and nanostructural properties in the OIH matrix due to Li + -loading and plasticizer (PPO n ) blending by: o Differential Scanning Calorimetry (DSC). o Room temperature Infrared spectroscopy (FTIR). o In situ Raman spectroscopy data collection during programed temperature change. o In situ Small Angle X-Ray Scattering (SAXS) data collection during programed temperature change.  Analysis of the effect of Li + -loading on the OIH matrix vibrational properties as well as the active sites in the -O-Li-O-bonding involving a polar oxygen ether type by: o Room temperature Infrared spectroscopy (FTIR). o In situ Raman spectroscopy data collection during programed temperature change.  Ionic conductivity analyses of the OIH:Li + electrolytes and its dependence on the temperature, PEO 1900 structural conformation and PPO 2000 fraction in the Ux PEO 1900 :Li + :U-1-x PPO 2000 :Li + OIH blend: o Impedance Spectroscopy.  Correlation of Ionic Conductivity/Structural properties.

Table 3 .

 3

	1: Table content the volume of water (μl) and the mass of europium salt (g), to satisfy the relationship [H 2 O]/[Si]=4 [O carbonyl ]/[Li + ]=15, and [O carbonyl ]/[Eu 3+ ]=3, respectively, for a
	mass of 0.5 g of the precursor.
	PEO mw. (g.mol -1 )	H 2 O volume (μl)	C 2 F 5 LiNO 4 S 2 mass (g)	EuCl 3 x 6 H 2 O mass (g)
	1900	30	0.176	0.052
	POs mw. (g.mol -1 )
	230	99	0.033	0.230
	2000	29	0.127	0.049
	4000	16	0.145	0.027

Table 3 . 2

 32

	OIH material	H 2 O volume (μl)	C 2 F 5 LiNO 4 S 2 mass (g)	K (cm -1 )
	U-PPO 2000	28.9	0.127	0.91
	U-0.8 PPO 2000 /U-0.2 PEO 1900	29.0	0.136	0.66
	U-0.5 PPO 2000 /U-0.5 PEO 1900	29.5	0.151	0.66
	U-0.2 PPO 2000 /U-0.8 PEO 1900	29.8	0.160	0.55
	U-PEO 1900	30.0	0.176	0.52

: Volume of water (μl) and the mass of lithium salt (g) used to satisfy the relationship [H 2 O]/[Si]=4 and [O carbonyl ]/[Li + ]=15, and the electrical geometric factor of the Ux PPO 2000 /U 1- x PEO 1900 poly-electrolytes.

Table 4 .

 4 1.

											Peak Analysis
							Data Set:[Book1]Sheet1!0h		Date:14/06/2016
							Baseline:Line
							Chi^2=9.42831E-006		Adj. R-Square=9.99253E-001	# of Data Points=95.
							SS=7.73121E-004			Degree of Freedom=82.
	Absorbance	2 U-PEO 1900 nd derivate	"Amide I" 1640 cm -1	1560 cm -1 "Amide II"		Absorbance	1680	1660	1642	1560
		1680 cm -1
			1652 cm -1	1635 cm -1	1560 cm -1					Peak Analysis
	1750	1700		1650	1600	1550	1500 Data Set:[Book1]Sheet1!0h		Date:14/06/2016
			Wavenumber (cm -1 )	0h	1700 Baseline:Line Fitting Results SS=4.25138E-003 Chi^2=6.96947E-005		1650	1600 Wavenumber (cm Degree of Freedom=61. -1 ) Adj. R-Square=9.99056E-001	1550	1500 # of Data Points=74.
		2 U-PEO 1900 -Eu nd derivate	3+ -doped		Peak Index 1. 2. 3. 4.	Peak Type Gaussian Gaussian Gaussian Gaussian	Area Intg 1.29019 8.84628 13.94349 4.38565	FWHM 17.37576 31.53757 36.09683 33.37639	1612	Max Height 0.07036 0.26351 0.36396 0.12379	Center Grvty 1681.39322 1638.75081 1559.93874 1659.80238	Area IntgP 4.53245 31.07706 48.98364 15.40685
											1590
	Absorbance	1644 cm -1	1588 cm -1	1550 cm -1		Absorbance			1640	1565
				1612 cm -1
	1700	1650			1600	1550	1500	1700			1650	1600	1550	1500
			Wavenumber (cm -1 )	Fitting Results			Wavenumber (cm -1 )
							Peak Index	Peak Type	Area Intg	FWHM	Max Height	Center Grvty	Area IntgP
							1.	Gaussian	3.23206	21.72847	0.13974	1640.75381	8.29939
							2.	Gaussian	17		22.99858	0.69441	1612	43.65322
							3.	Gaussian	16.33121	28.8695	0.53144	1589.91531	41.93587
							4.	Gaussian	2.38003	22.75481	0.09855	1565.61619	6.11152

Table 4 . 1 :

 41 Table containing the values of the Gaussian fitting parameters for the Amide I and Amide II regions of the U-PEO 1900 and U-PEO 1900 :Eu 3+ .

	Fitting Parameters	U-PEO 1900	U-PEO 1900 :Eu 3+
	Chi^2	9.43E-6	6.97E-5
	Adj. R^2	0.999	0.999
	Frequency (cm -1 )	Area int. (%)	Attribution	Ref
	1560 1564	48.98		N-H in plan	168
	1565		6.11
	1590 1612	------	41.93 43.65	δ(NH 2 ) --Eu 3+ ---O carb.	172
	1640 1642	31.08	8.3	H-O carb. (ordered)
	1656 1660	15.40	---	H-O carb. (desordered)	187
	1674 1680	4.5	---	C=O carb.

free  4.

2.3 FT-Raman analysis of the OIH:Eu 3+ complexes;

  emission spectra. The dependence of Ω 1,2 values as a function of the UV-light irradiation time of the OIH:Eu 3+ complex is found in (Table4.2).Both non-irradiated OIH:Eu 3+ complexes have been shown to have a high value of Eu 3+ asymmetry in its local surroundings, which can be seen by their high Ω 1,2 parameter value (~ 4.1), which is even higher than several oxide glasses 207 . This fact is in agreement with the apparition of the forbidden 5 D 0 → 7 F 0 transition. On the other hand, the photo-degradation plays a different role in PEO 1900 and PPO 2000 materials. It is seen from Table4.2 that Ω 1,2 values decrease in the first stage of exposure, and then increases after 5 and 3 h for U-PEO 1900 and U-PPO 2000 , respectively. It can be explained

	products 221 .
	After 3 h of UV irradiation, the Ω 1,2 value of U-PPO 2000 :Eu 3+ is almost two times
	higher than U-PEO 1900 :Eu 3+ . U-PPO 2000 :Eu 3+ remains non-crystalline even after the UV-
	irradiation. On the other hand, there is a slight increase of the symmetry for the U-
	PEO 1900 :Eu 3+ , which can be explained in following way: for semi-crystalline polymers,
	like PEO 1900 , photo-ageing starts in the amorphous phase due to the easy diffusion of
	oxygen to the unordered chains. It was already well-known that PEO 1900 has an ordered
	helical (gauche) conformation below the fusion temperature 222 . This ensures that Eu 3+
	cations are accommodated in a distinctly, more distorted environment in PPO 2000 (trans)
	than in PEO 1900 (gauche)

by an initial formation of chromospheres, which are unstable and undergo photolysis during prolonged irradiation. Kowalonek, J., et al. reported that for PEO + CoCl 2 UV photo-ageing, small crystallites are reordered and replaced by slowly growing of larger crystallites. This means that during the early step of photo aging of the OIH:Eu 3+ complex, the formation of chromophores in the hybrid matrix prevails over the photo-

Table 4 .

 4 2: I( 5 D 0 → 7 F 2 ) / I( 5 D 0 → 7 F 1 ) ratio (Ω 1,2 ), of the Eu 3+ -OIH complex, exposed to different UV-light irradiation times.

	Time of Irradiation (hours)	U-PEO 1900 :Eu 3+	Ω 1,2	U-PPO 2000 :Eu 3+
	0	4.07		4.13
	1	2.73		2.95
	3	1.70		3.49
	5	2.48		4.72
	7	2.79		4.11
	10	2.25		4.43

Table 6 . 1 :

 61 Attribution of the FTIR spectroscopy bands for the U-PEO 1900 and U-PPO 2000 OIH thin film (50 µm) matrices, Li + -unloaded and Li + -loaded.

	Frequency (cm -1 )	U-PEO 1900	Attribution U-PEO 1900 :Li	Refs
	1060	---	Anion SO 3
	1105	---	Li -O ether
	1108	ν as (C-O-C)	---
	1135	Rock (CH 2 ) crys	Rock (CH 2 ) amorph	103, 142, 185, 187, 189,
	1195	Anion CF 3	Anion CF 3	190, 209, 217, 236
	1334	Bending (CH 2 ) crys	Bending (CH 2 ) amorph
	1355	Wagging (CH 2 ) crys	Wagging (CH 2 ) amorph
	1457	Bending (CH 2 ) crys	Bending (CH 2 ) amorph
	1564	'Amide II'	'Amide II'
	1654	'Amide I'	'Amide I'

Table 6 . 2 :

 62 Table containing the mathematical fitting values of the Amide I and Amide II regions of U-PEO 1900 and U-PEO 1900 :Li + .

	Fitting Parameters	U-PEO 1900	U-PEO 1900 :Li
	Chi^2	9.43E-6	1.89E-5
	Adj. R^2	0.999	0.999
	Frequency (cm -1 )		Area int. (%)	Attribution	Refs
	1560 1564	48.98	52.22	N-H in plan	185, 187
	1565
	1640 1642	31.08	14	H-O carb. (ordered)
	1656		28.36	H-O carb.	168,236
	1660	15.40		(desordered)
	1674 1680	4.5	5.3	C=O carb. free

Table 6 .

 6 3: Attribution of the Raman bands of Li + -unloaded and Li + -loaded U-PEO 1900 and U-PPO 2000 OIH.

	Band frequency (cm -1 )	Attribution	Reference
	U-PEO 1900 / U-PPO 2000 740	[C 2 F 5 NO 4 S 2 ] -free anions	35
	807 / 810 845 / 866	Poly-ether conformational backbone (O-C-C-O)	231
	883 / 933
	1048 / 1015	δ S (Si-O) 3 deformations	35
	1098 / 1095 1140 / 1139 1286 / 1297	Si-OCH 3 groups Asymmetric stench of aliphatic ether ν S (C-O-C) phase twisting mode of the -(CH 2 ) n -	233 196
	---/ 1347	δ S (CH) symmetric deformation from tertiary carbon	229
	---/ 1406	δ S (CH 3 ) symmetric deformation
	1450 / 1456 1473 / ---	δ S (CH), δ S (CH 2 ) and δ A (CH 3 ) deformations	202
	6.4 Nanostructure:

 6.4.1 Room Temperature SAXS patterns;

Table 6 .

 6 4: Values of the thermal expansion coefficient represented by the slope of the curve from the average distance of the siloxane correlation peak as a function of the temperature.

	PPO 2000 fraction		θ at a middle range of temperature	Mixture Law
	0	Puro Li +	0.0091 0.0087	------
	0.2	Puro Li +	0.0009 0.0013	0.0075 0.0022
	0.5	Puro Li +	0.00200 0.00110	0.0051 0.0056
	0.8	Puro Li +	0.0007 0.0017	0.0028 0.0037
	1	Puro Li +	0.00120 0.00250	------

O

This leads to an increase in ion mobility and segmental mobility, which will assist ionic transport and virtually compensate for the hindering effect of ion clouds.