Romain David
email: romain.david@erinha.eu

Laurent Bouveret

Lorraine Coché

Pedro Pizzigatti Corrêa

Rorie Edmunds

Ana Heredia

Jean-Luc L Jung

Yasuhisa Kondo

Iwan Le Berre

Y Le Bras

E Lerigoleur

L Mabile

J Machicao

B Madon

Y Murayama

Margaret O'brien

T Osawa

H Raoul

A Richard

S Santos

A Specht

D Stepanyan

D Vellenich

L Wyborn

Mabile, L Dav

Data dictionary cookbook for research data and software interoperability at global scale

Keywords: PARSEC, Kakila, ERINHA-Advance

à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Dealing with complexity

• Developing data dictionary literacy is an essential work to imply scientists in variables definitions, • Enabling adaptability, portability, replicability and reproducibility implicates that software and workflows must be defined as all data in the data dictionary, • Addressing dimension issues in each context is necessary for all variables.

projects, the same cookbook

The PARSEC Project is building new tools for data sharing and reuse through a transnational investigation of the socioeconomic impact of protected areas.

The Kakila database centralizes and harmonizes marine mammal observation data for the AGOA sanctuary around the French archipelago of Guadeloupe, French Antilles.

The ERINHA-Advance project aims to support the operations of the ERINHA research infrastructure which is designed to generate data from transnational access research activities on highly pathogenic agents.

In these 3 global case-studies, similar challenges have arisen: to aggregate and interoperate pre-existing heterogeneous data at the global scale, and to share common tools to monitor, maintain quality, scan scale and cope with uncertainty.

As simple as possible!!

The common experience of our three projects showed that we need to proceed step by step as simply as possible and to ensure that each step is understandable for the whole community. It is necessary to improve access and re-use of all existing semantic materials and not trying to build a cathedral with a little spoon. -to Reuse existing vocabularies and ontologies (if several, choosing the better one). -to obtain a consensus between variables names and definitions. All terms must be community approved

Data dictionary cookbook

  Can some satellite images be used as proxys for socio-economic indicators?[Data dictionary principles] -Choose common definitions to enable comparisons between countries -Validate reusable definitions to ensure reproducibility of project resultsAbout the scientific question, examples of[ontologies, with a challenge: when there are several, choosing the better terms.All terms are community approvedData dictionary with [List of DEFINITIONS] approved by the whole community contain ALL [Scientific Questions], [List of ENTITIES], [List of QUALITIES], [Variables names: Entity_Quality_Dimentions_Units] and variables definitionsCommunity perimeter defined by: [Scientific Questions] Can we characterize cetacean presence in the waters of the Guadeloupe archipelago using several citizen science databases? [Data dictionary principles] -Choose common vocabulary to describe fields from heterogeneous databases -Adopt common variables description and values between databases About the scientific question, examples of [are: -to obtain a consensus for variables values between databases -to align with the existing data to Darwin Core vocabulary All terms are community approved Community perimeter defined by: [Scientific Questions] Can Biosafety level 4 laboratories compare their virologic in vivo studies results? [Data dictionary principles] -List all in vivo models, viruses, protocols and their data sensitivity -List and homogenize variables description for possible meta-analyses About the scientific question, examples of [

PARSEC is funded by the Belmont Forum through the National Science Foundation (NSF), The São Paulo Research Foundation (FAPESP), the French National Research Agency (ANR), and the Japan Science and Technology Agency (JST). ERINHA Advance is funded by ERINHA-Advance european program under grant agreement Nº824061.. Kakila database is funded by the LabEx DRIIHM French program "Investissements d'Avenir" (ANR-11-LABX-0010) and supported by the SO-DRIIHM project (ANR-19-DATA-0022). This work is partially funded by the EOSC-Life European program (grant agreement No. 824087).


Melisa Trejo-Maldonado

Luis Ernesto Elizalde
email: luis.elizalde@ciqa.edu.mx

Benjamin Le Droumaguet

Daniel Grande
email: grande@icmpe.cnrs.fr

Synthesis of Triazole-Functionalized Diblock Copolymers as Templates for Porous Materials

Keywords: diblock copolymers, CuAAC "click" reaction, triazole, porous materials

A versatile approach toward porous polystyrene-based frameworks functionalized with triazolyl moieties is reported. These porous materials were prepared from poly(D,L-lactic acid)-blockpoly(styrene-stat-4-azidomethylstyrene) (PLA-b-P(S-stat-4-AMS)) diblock copolymer precursors.

Upon macroscopic orientation and subsequent alkaline hydrolysis of the PLA block, such triazolylcontaining porous polystyrenes were produced. Experimentally, a PLA macroinitiator was synthesized by ring-opening polymerization (ROP) of D,L-lactide using a heterobifunctional initiator.

The prepared macroinitiator containing a terminal tertiary -bromo ester group allowed for further ATRP statistical copolymerization of styrene and 4-azidomethylstyrene, affording the second block, i.e. the P(S-stat-4-AMS) block. The styrene to 4-azidomethylstyrene molar ratio was tuned to obtain various compositions of the hydrophobic block. PLA macroinitiators and corresponding PLA-b-P(Sstat-4-AMS) diblock copolymers were fully characterized by size exclusion chromatography (SEC), 1 H and 13 C NMR, Fourier Transform Infrared (FT-IR) spectroscopy, and differential scanning calorimetry (DSC). Functionalization of PLA-b-P(S-stat-4-AMS) diblock copolymers with ptolylacetylene or 2-methyl-3-butyn-2-ol was carried out via copper-catalyzed azide-alkyne cycloaddition (CuAAC), yielding triazole ring in high yields (>90%). Finally, the porous structure of such functional polystyrene frameworks was examined by SEM.

Introduction

Over the last decade, functionalized porous materials have gained increasing interest from the research community in different areas, such as microelectronics, [START_REF] Tan | Block Copolymer Self-Assembly Directed Hierarchically Structured Materials from Nonequilibrium Transient Laser Heating[END_REF] energy storage, [START_REF] Singh | Effect of Molecular Weight on the Mechanical and Electrical Properties of Block Copolymer Electrolytes[END_REF] photonics, [START_REF] Tan | Synthesis and Formation Mechanism of All-Organic Block Copolymer-Directed Templating of Laser-Induced Crystalline Silicon Nanostructures[END_REF] separation, [START_REF] Dorin | Solution Small-Angle X-ray Scattering as a Screening and Predictive Tool in the Fabrication of Asymmetric Block Copolymer Membranes[END_REF][START_REF] Radjabian | Advanced porous polymer membranes from self-assembling block copolymers[END_REF] environmental remediation, [START_REF] Nunes | Block Copolymer Membranes for Aqueous Solution Applications[END_REF] and biotechnology, [START_REF] Nassif | From diatoms to silica-based biohybrids[END_REF] among others. The real breakthrough in these applications deals not only with their peculiar morphology but also with the specific properties they may offer, such as interaction between the porous material and the target molecules through a fast mass transfer, high specific surface area, and when hierarchically structured, they develop the capability of mimicking natural structures. [START_REF] Bertrand | Hierarchically porous bio-inspired films prepared by combining "breath figure" templating and selectively degradable block copolymer directed selfassembly[END_REF][START_REF] Montero De Espinosa | Bioinspired Polymer Systems with Stimuli-Responsive Mechanical Properties[END_REF] Actually, the porous materials by themselves cannot improve any useful property in the above-mentioned applications and require, in most cases, the introduction of chemical groups inserted in the backbone that can interact with metal ions, especially in the preparation of metal-organic frameworks (MOFs) [START_REF] Yao | A series of multidimensional MOFs incorporating a new N-heterocyclic building block: 5,5 ′ -di(pyridin-4-yl)-3,3 ′bi(1,2,4-triazole)[END_REF] or mesoporous metal-based materials (MMBMs). [START_REF] Zou | Recent advances in amphiphilic block copolymer templated mesoporous metal-based materials: assembly engineering and applications[END_REF] To date, porous polymeric materials can be prepared through several self-assembling procedures according to a bottom-up strategy; this technique notably relies on functional block copolymers, constituted of an inert block and a labile (sacrificial) one, [START_REF] Liu | Controlled ATRP Synthesis of Novel Linear-Dendritic Block Copolymers and Their Directed Self-Assembly in Breath Figure Arrays[END_REF][START_REF] Zalusky | Ordered Nanoporous Polymers from Polystyrene-Polylactide Block Copolymers[END_REF] which undergo self-assembly followed by the elimination of the labile block. Polystyrene-block-poly(D,L-lactic acid) (PS-b-PLA) semi-degradable diblock copolymers have been widely used in the two last decades for the preparation of such nanoporous polymers. The porosity has been created either by selective degradation of the PLA block or alternatively by a smarter strategy implying the selective cleavage of a chemical junction present between alien blocks. [START_REF] Ryu | Highly Ordered Gold Nanotubes Using Thiols at a Cleavable Block Copolymer Interface[END_REF][START_REF] Droumaguet | Clickable" thiol-functionalized nanoporous polymers: from their synthesis to further adsorption of gold nanoparticles and subsequent use as efficient catalytic supports[END_REF][START_REF] Kang | Synthesis of Photocleavable Poly(styrene-block-ethylene oxide) and Its Self-Assembly into Nanoporous Thin Films[END_REF][START_REF] Zhao | Functionalized Nanoporous Thin Films and Fibers from Photocleavable Block Copolymers Featuring Activated Esters[END_REF][START_REF] Gamys | Amine-functionalized nanoporous thin films from a poly(ethylene oxide)-block-polystyrene diblock copolymer bearing a photocleavable onitrobenzyl carbamate junction[END_REF][START_REF] Goldbach | Nano-to Macro-Sized Heterogeneities Using Cleavable Diblock Copolymers[END_REF][START_REF] Goldbach | Synthesis and Thin Film Characterization of Poly(styreneblock-methyl methacrylate) Containing an Anthracene Dimer Photocleavable Junction Point[END_REF][START_REF] Zhang | Highly Ordered Nanoporous Thin Films from Cleavable Polystyrene-block-poly(ethylene oxide)[END_REF][START_REF] Yurt | Scission of Diblock Copolymers into Their Constituent Blocks[END_REF][START_REF] Satoh | A facile synthesis of clickable and acidcleavable PEO for acid-degradable block copolymers[END_REF][START_REF] Poupart | Porous Gold Nanoparticle-Decorated Nanoreactors Prepared from Smartly Designed Functional Polystyrene-block-Poly(d,l-Lactide) Diblock Copolymers: Toward Efficient Systems for Catalytic Cascade Reaction Processes[END_REF][START_REF] Rao | Synthesis and self-assembly of dynamic covalent block copolymers: towards a general route to pore-functionalized membranes[END_REF][START_REF] Li | Nanoporous Films with Sub-10 nm in Pore Size from Acid-Cleavable Block Copolymers[END_REF][START_REF] Glassner | Formation of nanoporous materials via mild retro-Diels-Alder chemistry[END_REF] The latter has notably allowed for the facile release of chemical functionalities of interest that can be further implemented for pore surface functionalization. When porous metal-based materials are demanded, the addition of metal ions are common; however, the only expected interactions between the copolymer backbone and the metal ion are through Van der Waals forces. In this regard, few publications emphasize improving the strength of these interactions by functionalizing a stable block copolymer with chemical groups of interest that can reach stronger interactions with the metal ions by coordinate covalent bonds. [START_REF] Arredondo | A new route toward imidazolinefunctionalized porous polymeric materials from corresponding polystyrene-polylactide diblock copolymers[END_REF][START_REF] He | Assessment of magnetic core-shell mesoporous molecularly imprinted polymers for selective recognition of triazoles residual levels in cucumber[END_REF][START_REF] Ji | Hierarchical honeycombstructured films by directed self-assembly in "breath figure" templating of ionizable "clicked" PH3T-b-PMMA diblock copolymers: an ionic group/counter-ion effect on porous polymer film morphology[END_REF][START_REF] Song | Mesoporous Polystyrenes via Lamellar Block Copolymer Assembly[END_REF] The use of amphiphilic block copolymers followed by an induced or cooperative self-assembly has noteworthy advantages; the extent of the interactions between antagonist blocks could be predicted, based on the chemical nature of each block and their intrinsic physicochemical properties such as molar mass, molar mass distribution, block composition and solubility. [START_REF] Matyjaszewski | Atom Transfer Radical Polymerization (ATRP): Current Status and Future Perspectives[END_REF] Amphiphilic block copolymers with tunable molar masses, narrow molar mass distributions, and high endfunctionality can be obtained by controlled radical polymerization (CRP) techniques. Particularly, reactive/functional end-groups can promote post-polymerization reactions to obtain functionalized macromolecules. [START_REF] Droumaguet | Clickable" thiol-functionalized nanoporous polymers: from their synthesis to further adsorption of gold nanoparticles and subsequent use as efficient catalytic supports[END_REF][START_REF] Poupart | Porous Gold Nanoparticle-Decorated Nanoreactors Prepared from Smartly Designed Functional Polystyrene-block-Poly(d,l-Lactide) Diblock Copolymers: Toward Efficient Systems for Catalytic Cascade Reaction Processes[END_REF][START_REF] Arredondo | A new route toward imidazolinefunctionalized porous polymeric materials from corresponding polystyrene-polylactide diblock copolymers[END_REF] Atom Transfer Radical Polymerization (ATRP) is one of the most employed CRP processes due to its viability to polymerize a wide spectrum of functional monomers in a controlled manner, particularly for post-polymerization reactions, such as block extension or end group functionalization. Besides, adding one or more blocks with dissimilar chemistry is possible towards the preparation of biphasic systems when ATRP is combined with other polymerization techniques. These chemical features inherent to each block enable their phase segregation, promoting self-assembly of the domains at a nano/mesoscale, resulting in a hierarchically ordered structure.

Herein, we report on the synthesis of functionalized poly(D,L-lactide)-block-poly(styrene-statistical-4-azidomethylstyrene) (PLA-b-P(S-stat-4-AMS) diblock copolymers and their further functionalization to afford the corresponding diblock copolymers exhibiting various quantities of triazolyl moieties which could be used in the preparation of porous functional polymeric materials.

The as-obtained amphiphilic block copolymer is constituted of a stable block containing a tuned quantity of triazolyl groups embedded in the polymer chain and of a degradable PLA block that is notably sensitive to alkaline conditions. In the functionalized polystyrene block, the triazolyl groups are incorporated through the concomitant polymerization of styrene and 4-azidomethylstyrene (4-AMS), used as co-monomer, followed by the copper-catalyzed azide-alkyne cycloaddition (CuAAC) of two different acetylenic compounds. Further, some features of the porous morphology arising from such triazolyl functionalized diblock copolymers are given.

Experimental Section

Materials

The solvents were dried, as already reported in the literature. [START_REF] Armarego | Purification of Laboratory Chemicals[END_REF] Copper (I) bromide and copper (I) chloride (Aldrich, 99%) were purified by stirring in glacial acetic acid, then with several successive washings with methanol, and finally with anhydrous diethyl ether before drying overnight under vacuum. Dimethylaminopyridine (DMAP, >99%), 2-bromoisobutyryl bromide (>98%), N,N,N',N'',N''-pentamethyldiethylenetriamine (PMDETA, 99%), 4-chloromethyl styrene (97%), triethylamine (TEA, 99.5%), ethylene glycol (99.8%, anhydrous), and sodium azide (NaN3, ≥99.5%) were obtained from Aldrich and used as received. Styrene (Aldrich, 99%) was washed with NaOH and distilled from LiAlH4 under vacuum prior to use. D,L-Lactide (Aldrich, 99%) was lyophilized from toluene overnight prior to use. Other reagents and solvents were used without any further purification procedures unless otherwise stated.

Synthesis of 2-hydroxyethyl 2-bromoisobutyrate (HEBI) (1)

The synthesis of HEBI is adapted from an already reported procedure. [START_REF] Grande | Functionalized ordered nanoporous polymeric materials: From the synthesis of diblock copolymers to their nanostructuration and their selective degradation[END_REF] It is as follows: Ethylene glycol (5.54 g, 89.4 mmol) and TEA (6.78 g, 67.0 mmol) were placed into a 250 mL round-bottom flask and diluted with 50 mL of dichloromethane. 2-bromoisobutyryl bromide (5.14 g, 89.0 mmol) was added dropwise into the mixture in a time-lapse of 2 h at 0 °C. Upon completion of the addition, the reaction mixture was warmed to room temperature, and a catalytic amount of DMAP was added to the reaction. Finally, the reaction mixture was refluxed for 3 additional h. The obtained product was purified via vacuum distillation, isolating a colorless viscous liquid (10.19 g, 45 % yield). 1 H NMR (CDCl3 at 25 °C, 500 MHz): δ (ppm): 4.2 (t, 2H, J = 4.30 Hz, C(=O)O-CH2); 3.8 (t, 2H, J = 4.5 Hz, CH2-OH); 1.9 (s, 6H, -CH3). 13 . GC-MS (E.I.): m/z: [M .+ ]: 210 [START_REF] Ji | Hierarchical honeycombstructured films by directed self-assembly in "breath figure" templating of ionizable "clicked" PH3T-b-PMMA diblock copolymers: an ionic group/counter-ion effect on porous polymer film morphology[END_REF], 212 (30)

Synthesis of 4-azidomethylstyrene (4-AMS) (3)

4-chloromethylstyrene (10.0 g, 65 mmol) and sodium azide (8.45 g, 130 mmol) were mixed with 70 mL acetone in a 100 mL round-bottom flask. The mixture was refluxed for about 90 h. The organic phase was diluted with CHCl3, washed with H2O, dried over MgSO4, and vacuum-dried to afford the desired product as an orange viscous liquid (10.21 g, 98% yield). 1 (Aromatic Carbon), 114.4 (-CH=CH2), 54.6 (-CH2-N3). FT-IR (film in KBr): νC=C-H 3000 cm -1 , ν-N3 2097.60 cm -1 . GC-MS (E.I.): m/z: [M .+ ]: 159 [START_REF] Ji | Hierarchical honeycombstructured films by directed self-assembly in "breath figure" templating of ionizable "clicked" PH3T-b-PMMA diblock copolymers: an ionic group/counter-ion effect on porous polymer film morphology[END_REF], 116.9 (100).

General procedure for the synthesis of poly(D,L-lactic acid) PLA macroinitiator (2)

2-hydroxyethyl-2-bromo-2-methyl propanoate (HEBI, 0.39 g, 1.87 mmol) and tin (II) 2ethylhexanoate (1.53 g, 3.75 mmol) were mixed with 40 mL dry toluene in a 100 mL Schlenk tube.

The solution was degassed with 3 freeze-pump-thaw cycles. Inside a glove box, 1,4-dioxane-2,5dione (D, L-lactide) (5.0 g, 69.3 mmol) was added into a 30 mL quartz tube containing one-third of the solution previously prepared. This process was repeated twice in two more tubes. Each tube was place independently in a microwave reactor at 110 °C for 5 h and 30 min. The device was programmed to reach such a temperature after 5 min from room temperature. At the end of the reaction, toluene was evaporated, the residue was dissolved in dichloromethane and precipitated in a mixture 1/1 hexane/diethyl ether: 1/1 (v/v). The obtained solid (4.65 g, 93% yield) was dried under vacuum for at least 12h in each case and was further analyzed by 1 H NMR, 13 C NMR and SEC.

General procedure for the synthesis of poly(D,L-lactic acid)-block-poly(styrene-stat-4azidomethylstyrene) copolymer (4)

Herein is described the general procedure to prepare a P(S-stat-4-AMS) block containing 5 mol. % 4-azidomethylstyrene in the hydrophobic segment of the block copolymer. In a 100 mL Schlenk tube, copper (I) chloride (0.055 g, 0.55 mmol) and PMDETA (0.14 g, 0.83 mmol) were mixed to form the catalytic complex using toluene as solvent (5 mL). After 15 min, the PLA macroinitiator (2) (4.61 g) dissolved in 15 mL toluene was added to the reaction flask. Then, 4-azidomethylstyrene (0.54 g, 3.4 mmol) diluted in styrene (6.26 g, 60.2 mmol) and 15 mL toluene were successively added to the reaction mixture. Upon homogenization of the reaction mixture, it was submitted to three freezepump-thaw cycles, placed into an oil bath at 90 °C so as to trigger the polymerization and stirred at this temperature for 8 h. At the end of the reaction, the solution was concentrated under vacuum, dissolved in CHCl3, and passed through a pad of silica to remove the copper catalyst. The polymer solution was concentrated and precipitated into a large volume of methanol. This operation was repeated 2-3 times to remove totally unreacted monomer. After the pure polymer was vacuumdried, it was analyzed by 1 H NMR, 13 C NMR, and SEC.

General procedure for the diblock copolymer triazole functionalization (5)

In a 50 mL round-bottom flask, copper (I) bromide (0.011 g, 0.077 mmol), PMDETA (0.013 g, 0.077 mmol) and toluene (10 mL) were mixed. In a second 50 mL round-bottom flask, the synthesized copolymer (1.0 g, 0.077 mmol) and 4-ethynyltoluene (0.05 g, 5.5 mmol) were mixed and dissolved in 5 mL toluene, the resulting solution was transferred via a cannula into the reaction flask containing the catalyst under inert atmosphere. The reaction mixture was stirred for 24 h at room temperature (~25 °C). Afterward, the reaction mixture was passed through a pad of silica to remove the copper catalyst, and the functionalized polymer was precipitated in a large volume of methanol.

The functionalized polymer, obtained as a powder (0.64 g, 65% yield), was vacuum-dried and analyzed by 1 H NMR, 13 C NMR, and FT-IR.

Mechanical orientation of diblock copolymer matrices

A stainless-steel channel die was used to help the phase separation to occur and thus obtain oriented nanodomains in the different copolymers. Further characteristics of this device can be found in a previous report. [START_REF] Droumaguet | Clickable" thiol-functionalized nanoporous polymers: from their synthesis to further adsorption of gold nanoparticles and subsequent use as efficient catalytic supports[END_REF] Briefly, a small amount of previously pressed copolymer film was placed in the channel die between two stripes of Teflon. The channel die was heated at 120 °C in a hydraulic press and subjected to constant pressure load for 1 h. Afterward, the channel die was annealed in a vacuum oven at 160 °C overnight.

Solvent vapor annealing orientation of diblock copolymers

A few drops of diblock copolymer solution (concentration of 20 mg.mL -1 in dichloromethane) were deposited onto a small silicon wafer surface (approximately 1 cm 2 ) and spin-coated at 400 rpm for 15 sec and 2000 rpm for 40 sec. The obtained thin films were vacuum-dried prior to the annealing.

The supported thin films were later placed inside a closed glass chamber and exposed to solvent vapors of tetrahydrofuran for different periods of time. Samples were vacuum-dried prior to SEM observations.

Selective hydrolysis of PLA block in oriented block copolymer thin films

The oriented PLA block was removed using a 3M NaOH aqueous solution. Experimentally, the specimen sample was immersed in the alkaline solution at 60 °C and gently shaken on an orbital shaking plate. The hydrolysis reaction times were very different depending on the morphology of the samples: overnight for the thin films prepared on silicon wafer surfaces and almost one month for the parallelograms obtained by mechanical orientation through channel die processing. Once hydrolysis was completed, the samples were rinsed successively with water and ethanol before vacuum-drying overnight and further observation by SEM.

Instrumentation

The 1 H and 13 C NMR studies were realized on a Bruker Avance III spectrometer (500 MHz and 125 MHz, respectively) in CDCl3 with TMS as an internal standard. FT-IR spectra were recorded on a Nicolet Magna-IR 550 spectrometer using the attenuated total reflection (ATR) and KBr sample holder, between 4000 and 450 cm -1 , with an average of 32 consecutive scans and a resolution of 4 cm -1 . Size Exclusion Chromatography (SEC) analyses were performed on a system equipped with a Spectra-Physics P100 pump, two PL gel 5 μm mixed-C columns (Polymer Laboratories), and a Shodex RI 71 refractive index detector along with a Wyatt Technologies eight-angle laser light scattering (LLS) detector. The eluent was THF at a flow rate of 1 mL.min -1 . Calibration curves for the RI detector were obtained with polystyrene standards from Polymer Labs (PS standards in the range of 1350-1,997,000 Da). Scanning Electron Microscopy (SEM) was performed on a MERLIN microscope from Zeiss equipped with InLens and SE2 detectors using a low accelerating tension (2-3 kV) with a diaphragm aperture of 30 μm. Field Emission SEM was performed on a JEOL JSM 7401F coupled with an energy dispersive X-ray (EDX) detector. The samples were first coated with a 4-nm thin layer of palladium/platinum alloy in a Cressington 208 HR sputter-coater. Thermal analyses were realized on a calorimeter model 9105 from TA Instruments.

Results and Discussion

Synthetic pathway

Inserting chemical functions of interest at the pore surface of polymer-based membranes is often a challenging task and is mainly driven by the synthetic strategy implemented to prepare the precursor block copolymers. Azide moieties seem to be chemical functionalities of choice to introduce chemical grafts on the pending chains of a (co)polymer through further postpolymerization modification via the well-known copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction, a so-called "click" reaction. Such a versatile chemical reaction has hitherto been widely applied in polymer chemistry for easy and straightforward functionalization of various natural or synthetic macromolecules, either on pending chains or on termini of the backbone, as reported by different reviews. [START_REF] Binder | Click' Chemistry in Polymer and Materials Science[END_REF][START_REF] Binder | Click' Chemistry in Polymer and Material Science: An Update[END_REF][START_REF] Moses | The growing applications of click chemistry[END_REF] The CuAAC reaction indeed allows for the formation of triazolyl groups, well-known as metal cations scavengers, as they allow for the formation of coordination bonds with diverse oxidized metallic species. To that extent, a certain number of examples dealing with 4-azidomethylstyrene-based homo-or copolymer materials has been reported in the recent literature to design such azido-functionalized macromolecular structures/materials. [START_REF] Choi | High Capacitance, Photo-Patternable Ion Gel Gate Insulators Compatible with Vapor Deposition of Metal Gate Electrodes[END_REF][START_REF] Doran | Graft polymer growth using tandem photoinduced photoinitiator-free CuAAC/ATRP[END_REF][START_REF] Gu | High Toughness, High Conductivity Ion Gels by Sequential Triblock Copolymer Self-Assembly and Chemical Cross-Linking[END_REF][START_REF] Li | Click synthesis and reversible electrochromic behaviors of novel polystyrenes bearing aromatic amine units[END_REF][START_REF] Li | Double Click Synthesis and Second-Order Nonlinearities of Polystyrenes Bearing Donor-Acceptor Chromophores[END_REF][START_REF] Lorenz | Macroporous Polymer-Protein Hybrid Materials for Antibody Purification by Combination of Reactive Gelation and Click-Chemistry[END_REF][START_REF] O'shea | Sequence-controlled copolymers of 2,3,4,5-pentafluorostyrene: mechanistic insight and application to organocatalysis[END_REF][START_REF] Song | High-performance triazolecontaining brush polymers via azide-alkyne click chemistry: a new functional polymer platform for electrical memory devices[END_REF][START_REF] Sun | Light Harvesting Arrays of Polypyridine Ruthenium(II) Chromophores Prepared by Reversible Addition-Fragmentation Chain Transfer Polymerization[END_REF][START_REF] Urbani | Reactive Alkyne and Azide Solid Supports To Increase Purity of Novel Polymeric Stars and Dendrimers via the "Click" Reaction[END_REF][START_REF] Yao | Hairy fluorescent nanoparticles from one-pot click chemistry and atom transfer radical emulsion polymerization[END_REF] These macromolecular materials can be engaged in CuAAC reaction with various alkynes to produce the corresponding triazolyl-containing (co)polymers. Such materials can present some interesting coordination properties with metallic ions. Such homo-or copolymers in which are embedded 4-AMS can be obtained from the (co)polymerization of 4chloromethylstyrene (4-CMS) and further azidation of the corresponding (co)polymers. [START_REF] Choi | High Capacitance, Photo-Patternable Ion Gel Gate Insulators Compatible with Vapor Deposition of Metal Gate Electrodes[END_REF][START_REF] Doran | Graft polymer growth using tandem photoinduced photoinitiator-free CuAAC/ATRP[END_REF][START_REF] Gu | High Toughness, High Conductivity Ion Gels by Sequential Triblock Copolymer Self-Assembly and Chemical Cross-Linking[END_REF][START_REF] Li | Click synthesis and reversible electrochromic behaviors of novel polystyrenes bearing aromatic amine units[END_REF][START_REF] Li | Double Click Synthesis and Second-Order Nonlinearities of Polystyrenes Bearing Donor-Acceptor Chromophores[END_REF][START_REF] Song | High-performance triazolecontaining brush polymers via azide-alkyne click chemistry: a new functional polymer platform for electrical memory devices[END_REF][START_REF] Sun | Light Harvesting Arrays of Polypyridine Ruthenium(II) Chromophores Prepared by Reversible Addition-Fragmentation Chain Transfer Polymerization[END_REF][START_REF] Urbani | Reactive Alkyne and Azide Solid Supports To Increase Purity of Novel Polymeric Stars and Dendrimers via the "Click" Reaction[END_REF] Another alternative relies on the direct (co)polymerization of 4-AMS. [START_REF] Lorenz | Macroporous Polymer-Protein Hybrid Materials for Antibody Purification by Combination of Reactive Gelation and Click-Chemistry[END_REF][START_REF] O'shea | Sequence-controlled copolymers of 2,3,4,5-pentafluorostyrene: mechanistic insight and application to organocatalysis[END_REF][START_REF] Yao | Hairy fluorescent nanoparticles from one-pot click chemistry and atom transfer radical emulsion polymerization[END_REF] This functional monomer can be homo-or copolymerized in the presence of other monomer, e.g. (2,3,4,5,6pentafluoro)styrene. The proposed synthetic route (Figure 1) followed in this work entails the preparation of a poly(D,L-lactic acid) (PLA) macroinitiator (2) from a heterobifunctional initiator [START_REF] Tan | Block Copolymer Self-Assembly Directed Hierarchically Structured Materials from Nonequilibrium Transient Laser Heating[END_REF] containing both a terminal tertiary α-bromoester and a primary alcohol function. The latter should allow for the controlled ring-opening polymerization of D,L-Lactide. In contrast, the α-bromoester moiety should allow for the polymerization of the second block, namely a poly(styrene-stat-4azidomethylstyrene) (P(S-stat-4-AMS)) (4), via Atom Transfer Radical Polymerization (ATRP) methodology from PLA macroinitiator [START_REF] Singh | Effect of Molecular Weight on the Mechanical and Electrical Properties of Block Copolymer Electrolytes[END_REF]. Finally, the post-polymerization functionalization of the as-prepared isolated diblock copolymers was assessed by CuAAC reaction, [START_REF] Kim | Facile Synthesis of Amphiphilic Bottlebrush Block Copolymers Bearing Pyridine Pendants via Click Reaction from Protected Alkyne Side Groups[END_REF] to afford the corresponding triazolyl containing macromolecular materials (5a) or (5b), depending on the alkyne grafted.

Synthesis of initiator (1) (HEBI) and PLA macroinitiator (2)

Heterobifunctional initiator 2-hydroxyethyl-2-bromoisobutyrate (1) (HEBI) was selected as the starting initiator to prepare the functional diblock copolymers through two successive polymerization reactions. Indeed, this molecule contains a terminal tertiary α-bromoester, commonly used as ATRP initiator in styrene polymerization, [START_REF] Coessens | Functional polymers by atom transfer radical polymerization[END_REF] and another hydroxyl terminus that can promote the ring-opening polymerization (ROP) of D,L-lactide in the presence of a metal-based catalyst, i.e. SnOct2. According to the reported method, HEBI was synthesized and characterized by spectroscopic techniques to ensure its chemical structure. [START_REF] Grande | Functionalized ordered nanoporous polymeric materials: From the synthesis of diblock copolymers to their nanostructuration and their selective degradation[END_REF] Afterward, SnOct2-catalyzed synthesis of poly(D,L-lactic acid) (PLA) from HEBI initiator and D,L-lactide monomer was achieved at 110 °C in a microwave reactor for 5.5 h under moisture-free conditions. The experimental molar masses calculated by 1 H NMR were close to those theoretically expected, i.e. 8.0 and 15.0 kg.mol -1 , as shown in Table 1, thus demonstrating the good control of the ROP process. The PLA macroinitiator was purified by precipitation in a mixture hexane/diethyl ether, and the molar mass given by size exclusion chromatography (SEC) equipped with an eight-angle laser light scattering (LLS) detector. The molar mass distribution (Ð) was also given by SEC, while the functionalization degree was determined by 1 H NMR (Figure 2). The 1 H NMR spectrum of the vacuum dried product (2), shown in Figure 2, clearly demonstrated that the ROP of D,L-lactide from HEBI was successful. Characteristic PLA signals were observed, notably those with chemical shifts δ ~ 5.2 and 1.6 ppm for methine and methyl groups, respectively, together with those from the HEBI initiator, notably the 4 methylene protons at δ ~ 4.5 ppm. Additionally, a singlet at δ ~ 1.95 ppm was assigned to the six protons of the two equivalent methyl groups from the initiator in α-position of the bromine. The ultimate lactide unit inserted in the PLA block during ROP, was identified in the 1 H NMR spectrum with protons at δ = 5.05 ppm and at δ = 1.68 ppm, again assigned to the methine and methyl end group, respectively.

Synthesis of 4-azidomethylstyrene (4-AMS) (3)

4-azidomethylstyrene (4-AMS) (3) was obtained by nucleophilic substitution of chlorine from 4chloromethylstyrene by sodium azide in acetone, as already reported elsewhere. [START_REF] Lenstra | Catalytic Staudinger Reduction at Room Temperature[END_REF] Viscous orange liquid was obtained after evaporation of the acetone and isolated with nearly quantitative yield (98%). FT-IR spectroscopy (Figure S1 in Supplemental Information) confirmed the presence of the targeted compound with the appearance of a stretching absorption band νC-N3 = 2090 cm -1 , characteristic of the azide group covalently attached to the benzylic carbon. In addition, 1 H NMR spectrum of the pure product (Figure S2 in Supplemental Information) exhibited the shift of the singlet resonance peak of methylene protons in α-position of the chlorine from δ= 4.61 ppm to a new singlet resonance peak at δ = 4.26 ppm in agreement with the chemical shift of the methylene protons that are now in α-position of the azide moiety, a less electron withdrawing group than the halogen. 13 C NMR also corroborated these findings; a displacement of the chemical shift of the benzylic carbon was observed from 46.1 to 54.6 ppm, (Figure S3 in Supplemental Information), thus demonstrating the success of the nucleophilic substitution reaction. Mass spectrometry analysis (Figure S4 in Supplemental Information) indicated the presence of a molecular ion mass [M] +• = 116.9 m/z which confirmed the chemical structure of 4-azidomethylstyrene. This latter was stored in a glove box at -30 °C, due to its high reactivity.

Preliminary studies on styrene/4-azidomethylstyrene copolymerization from PLA macroinitiator

The preparation of diblock statistical copolymers from the PLA macroinitiator (2), styrene and 4-AMS was investigated. The synthesis of P(S-stat-4-AMS) (4) was assessed through a typical ATRP methodology. Hence, the copolymerization reaction of the 34 mol. % 4-AMS with styrene was performed in toluene using PMDETA/Cu (I) catalytic complex. The polymerization feed was kept at 100 °C for 20 h. After purification of the polymer by successive precipitations in methanol and vacuum-drying, the product was isolated as a light-yellow powder with 92% conversion, as calculated by gravimetric analysis. Upon dissolution of the PLA-b-P(S-stat-4-AMS) (4) diblock copolymer with chloroform, the copper-based catalyst was removed by passing the solution through a pad of silica. Nonetheless, larger solvent amounts were required to dissolve the product, despite this, a gel-like product was unexpectedly observed. 500 MHz 1 H-NMR analysis of the gel through a high-resolution magic angle spinning (HR-MAS) probe exhibits a resonance peak at 9.2 ppm which was assigned to an aldehyde proton. It was assumed that this type of products could arise from the redox reaction of the azide group with the PMDETA-copper (I) complex, involving some N2 release and leading to the formation of an imine group that can be further hydrolyzed to the corresponding aldehyde moiety. [START_REF] Kim | Redox reaction between benzyl azides and aryl azides: concerted synthesis of aryl nitriles and anilines[END_REF] Hence, we stated that the copper (I) complex could promote the reduction of the azide group and an aldehyde molecule could be produced, as depicted in Figure S5 (Supplemental Information). We thus hypothesized that 4-AMS generates free radicals by releasing N2 gas, [START_REF] Damiron | Crosslinked PDMS elastomers and coatings from the thermal curing of vinyl-functionalized PDMS and a diazide aliphatic crosslinker[END_REF] the nitrene radicals may be capable of initiating the polymerization by itself and therefore, promoting the crosslinking with other growing chains in a non-controlled fashion.

Consequently, gel formation may be promoted by an excess of radical species in the reaction medium: chain growing radicals and in situ formation nitrene radicals. It is likely that some of these nitrene radicals were accessible to react with the catalytic copper complex (Cu-L-X) and further yield aldehyde groups. To prove the extent of interactions between azide groups and other reagents employed in the ATRP polymerization, a kinetic study was performed. For such experiments, a 4-AMS/styrene molar ratio comprised between 5/95 to 34/66 and time lapses between 1 and 24 h were considered, while the temperature was kept constant at 90 °C (see Table S1 in Supplemental Information). Monomer conversion and gel content were routinely calculated and monitored, respectively. It was found out that higher amounts of 4-AMS were incorporated in the polystyrene chain when the initial 4-AMS/styrene molar fraction was lower than 0.15 and when the reaction time did not exceed 10 h. Under these specific experimental conditions, no gel formation was observed.

Preparation of PLA-b-PS and PLA-b-P(S-stat-4-AMS) copolymers (4)

Once the PLA macroinitiator was obtained, the tertiary α-bromo ester group capping one terminus of the polymer chain was used as a classic ATRP initiator. The PLA volume fraction (fPLA) targeted for such PS-b-PLA diblock copolymers was close to 0.35 since a hexagonally packed morphology is generally promoted after phase segregation in this case. However, it is also important to consider the 4-AMS/styrene molar ratio which is no longer higher than 0.15 in the stable polymer block.

Considering these variable parameters, two sets of PLA macroinitiators were employed for the concomitant ATRP polymerization of styrene and 4-AMS monomers: PLA126 (Mn SEC = 9.3 kg.mol -1 ) and PLA167 (Mn SEC = 12.3 kg.mol -1 ). For each macroinitiator, styrene degrees of polymerization of 140 and 185 were envisioned to obtain suitable PLA volume fractions, respectively. Moreover, three different 4-AMS/styrene molar ratios, i.e. 0, 0.05 and 0.10, were investigated for each PLA macroinitiator considered. The copolymerization reaction was carried out by dissolving the PLA macroinitiator in toluene in the presence of 4-AMS and styrene as the comonomers and PMDETA/Cu(I)Cl as catalyst under stirring at 90 o C for 10 h under inert atmosphere. The purification of the resulting copolymer was completed by removing the Cu(I)Cl/PMDETA catalytic complex by passing the polymerization mixture on a silica column and successive precipitations in a large volume of methanol. The diblock copolymers were characterized by spectroscopic techniques, such as ATR FT-IR and 1 H NMR but also thermal analysis and SEC. The molecular features of the as obtained diblock copolymers are gathered in Table 2 The integration of these protons was used to quantify the 4-AMS composition in the P(S-stat-4-AMS) polymer block. Finally, the methylene hydrogens bonded to the oxygen atoms belonging to the initiator, display broad signals in the 3.95-4.11 ppm region. In these sets of experiments, the synthesis of PS-b-PLA copolymers with no 4-AMS inserted in the chain was also considered. These materials were used as a reference, and characterization of such polymers was also achieved via 1 H NMR. ATR FT-IR analysis of the PLA-b-P(S-stat-4-AMS) diblock copolymers (4) (Figure S6 in Supplemental Information) showed characteristic absorption bands for the stretching of the carbonyl group at νC=O = 1750 cm -1 , and the bending absorption band at δC-H aromatic = 750 and 700 cm -1 for the aromatic protons of styrene. Finally, the stretching band of the C-N3 group at νC-N3 = 2094 cm -1 was also observed in the copolymers inserting 4-AMS. The DSC analysis of these diblock copolymers indicated the presence of two glass transition temperatures (Tg), namely Tg1 = 54.5 o C and Tg2 = 105 o C assigned to PLA and PS blocks, respectively (see Table S2 in Supplemental Information). Interestingly, a slight shift of each block Tg values was observed as compared to the theoretical Tg values of their respective homopolymers (Tg PLA = 50 °C, Tg PS = 100 °C). It is more likely that azido groups randomly distributed along the PS block may promote Van der Waals interactions with the lactide repeating units due to its intrinsic lability and may alter in consequence the block conformation. The molar mass distribution curve of the PLA126 (Mn SEC = 9.3 kg.mol -1 ) macroinitiator was compared with those of corresponding PLA126-b-P(Sm-stat-4-AMSn) copolymers. Figure 4 notably shows that SEC monomodal traces of such block copolymers, e.g. PLA126-b-P(S111-stat-4-AMS10) and PLA126-b-P(S97-stat-4-AMS4), are shifted towards higher molar masses when compared to the corresponding PLA126 macroinitiator (2), as expected from the polymerization of styrene and 4-AMS from the latter. Analogous results (Figure S7 in the supporting information) were obtained for the PLA167 (Mn SEC = 12.3 kg.mol -1 ) macroinitiator when compared to its corresponding PLA167-b-P(Sm-stat-4-AMSn) copolymers after copolymerization of styrene and 4-AMS.

Functionalization of diblock copolymers

The azido groups present along the PS backbone enable the functionalization of the copolymer to afford triazole derivatives (5a) or (5b) via CuAAC between PLA-b-P(S-stat-4-AMS) diblock copolymers and p-tolylacetylene or 2-methyl-3-butyn-2-ol, respectively, as depicted in Figure 1. The presence of triazole moieties in the porous polystyrene matrix will enhance its capacity to interact with metallic cations. It is worth mentioning that a different behavior in phase segregation of the triazolyl-functionalized copolymers is expected when compared to non-functionalized counterparts. This phenomenon relies on the presence of 4-AMS repeating units randomly inserted in the polystyrene block, leading to an increment of the polarity in the hydrophobic block. After functionalization, triazole functionalized polymers were obtained after precipitation in methanol and vacuum drying. 1 H NMR spectra of the CuAAC-mediated functionalized PLA-b-P(S-stat-4-AMS) diblock copolymers (see Figure 5, for instance) showed the presence of new resonance signals when compared to their copolymer precursors. Indeed, a new broad singlet appeared at δ = 7.6 ppm, ascribed to the aromatic triazolyl proton. Additionally, a clear shift of the signal ascribed to the benzylic protons, previously in α-position of the azide groups on the PLA-b-P(S-stat-4-AMS), observed from δ = 4.2 to 3.5 ppm, demonstrated the success of the CuAAC-mediated functionalization of the azido-functionalized diblock copolymer with p-tolylacetylene. The functionalization yield was determined by 1 H NMR and calculated by comparing the integration of the triazole ring proton at δ = 7.82 ppm with that of the benzylic methylene protons of the polystyrene block at δ = 1.92 ppm. Table 3 summarizes the so calculated CuAAC-mediated functionalization yields for the obtained copolymers. Furthermore, ATR FT-IR (Figure S6 in Supplemental Information) analysis of the functionalized copolymers did not show the presence of any characteristic asymmetric stretching band of the -N3 group at 2090 cm -1 upon CuAAC "click" reaction, thus demonstrating the success of the functionalization strategy. Additionally, absorption bands for the stretching band of the carbonyl group at 1750 cm -1 , and the bending of C-H aromatic bonds at 750 and 700 cm -1 were observed, demonstrating the presence of lactide and styrene in the copolymer and thus no degradation during the CuAAC reaction.

Macroscopic orientation of functional copolymers and pore generation

The prepared diblock copolymers (5a-b) have specific features to assist microphase segregation and further promote a hierarchical array to obtain nanostructured materials. As previously stated, the volume fraction of each block is one of the most important variables, and it has been previously reported that for PS-b-PLA copolymers, an asymmetric phase is preferable. To develop PLA cylinders within a PS matrix, values of PLA volume fraction (fPLA) must be equal to approximately 0.35. [START_REF] Grande | Functionalized ordered nanoporous polymeric materials: From the synthesis of diblock copolymers to their nanostructuration and their selective degradation[END_REF] For all synthesized block copolymers, fPLA was calculated according to the molar mass given by 1 H NMR spectroscopy. These block dimensions should enhance phase segregation towards a hexagonally close packed morphology, after the alignment of PLA domains in the PS matrix. We implemented two different orientation techniques to promote mesoscopic order in the copolymer matrix. The first technique relied on the mechanical orientation of the sample in solid state, thus obtaining a parallelepiped due to shear stress applied to a pre-oriented film of the copolymer in a confined space (i.e., channel die). Theoretically, the stress applied to the copolymer forced the chains to rearrange into a higher ordered conformation, shifting the system towards its most stable structure. After PLA hydrolysis, a nanoporous morphology of the resulting material could be observed, as depicted in Figure S8 (Supplemental Information), for the SEM image of a porous P(S329stat-4-AMS13) sample. Pore sizes of around 100 nm were detected. The second technique employed consisted in the orientation of the copolymer phases promoted by the swelling effect undergone in the presence of solvent vapors. SEM images showed the formed cavities in the functional polystyrene surface, after PLA alkaline hydrolysis (Figure 6 and Figure 7). Overall, pore formation was clearly observed; however, the magnitude of pore sizes was higher than that obtained with the channel die technique. Indeed, pore sizes in the range of 100 nm to 1µm were detected. Such broad pore size distributions might be attributed to ill-controlled solvent vapor annealing conditions for the copolymer precursors.

Conclusions

We have developed a new synthetic route to obtain functional diblock copolymers by utilizing a heterobifunctional ROP-ATRP initiator, i.e. 2-hydroxyethyl-2-bromoisobutyrate (HEBI). A poly(D,Llactic acid) macroinitiator was synthesized possessing a tertiary carbon-bromine end-group. Further copolymerization of 4-azidomethylstyrene (4-AMS) and styrene from PLA-Br macroinitiator was successfully carried out to generate the second azido-functionalized polystyrene block (P(S-stat-4-AMS)). Better copolymerization results were obtained with a 90/10: styrene/4-azidomethylstyrene molar ratio. Subsequent CuAAC reaction of the azide pending groups on the polymer backbone with two acetylenes was carried out, affording the resulting triazolyl functionalized copolymers with high functionalization yield. The 4-(azidomethyl) group present in the polystyrene block slightly shifted the PLA and PS glass transition temperatures toward lower values compared with the reference PLAb-PS block copolymers.

Upon macroscopic orientation and subsequent alkaline hydrolysis of the PLA block, triazolylcontaining porous polystyrenes were formed with varying pore sizes depending on the orientation technique used for the copolymer precursors. This straightforward approach paves the way to the versatile generation of functional porous polystyrene frameworks with tunable functionality via "click" chemistry. e Styrene molar fraction in the P(S-stat-4-AMS) random block. f PLA volume fraction as determined by 1 H NMR, assuming that densities of PS and PLA are 1.02 and 1.25 g/mL, respectively. Table 3. Functionalization yields observed for the CuAAC "click" modification of various PLA-b-P(Sstat-4-AMS) diblock copolymers with alkyne-appended compounds.

PLAn-b-P(Sm-stat-4-AMSp) Alkyne grafted Functionalization yield a (%)

1 ,

 1 C NMR (CDCl3 at 25 °C, 125 MHz): 171.3 (C=O), 64.1 (-CH2-), 60.7 (-OCH3), 51.4 (C-Br), 33.6 (-CH3). FT-IR (film in KBr): ν-OH 3300 cm -

  H NMR (CDCl3 at 25 °C, 500 MHz): δ (ppm): 7.38 (d, 2H, HA, JHA-HB = 8.09 Hz); 7.23 (d, 2H, HB, JHB-HA = 8.23 Hz); 6.68 (dd, 1H, H3, JH3-H1 = 10.97 Hz, JH3-H2 = 17.63 Hz); 5.73 (dd, 1H, H2, JH2-H1 = 0.84 Hz, JH2-H3 = 17.57 Hz); 5.24 (dd, 1H, H1, JH1-H2 = 0.64 Hz, JH1-H3 = 10.75 Hz); 4.26 (s, 2H, -CH2-N3). 13 C NMR (CDCl3 at 25 °C, 125 MHz): δ (ppm): 137.7 (Aromatic Carbon), 136.2 (-CH=CH2), 134.8 (Aromatic Carbon), 128.4 (Aromatic Carbon), 126.6

.

  Copolymerization of styrene and 4-AMS via ATRP proceeded with high conversions in the 90-100% range, regardless of the PLA size or initial comonomers/PLA macroinitiator ratio. Additionally, Mn SEC values close to the theoretical ones and Đ in the 1.2-1.5 range indicate that chain growth occurs in a controlled fashion. The 1 H NMR spectrum of the PLA126-b-P(S329-stat-4-AMS13) diblock copolymer in CDCl3 is shown in Figure 3. As expected, signals of the aromatic protons characteristic of the styrene and 4-AMS repeating units can be observed at δ = 7.4-6.3 ppm. Particularly, signals at δ = 7.40 and 7.26 ppm were assigned to the 4 aromatic protons of the 4-AMS repeating unit. The poly(D,L-lactic acid) repeating unit was identified by the presence of resonance peaks at 5.20 (-CH-) and 1.58 ppm (-CH3) together with a broad signal at δ = 4.24 ppm, assigned to the benzylic protons in α-position of the azide function.

Figure 1

 1 Figure 1 Synthetic route applied for the preparation of PLA-b-P(S-stat-4-AMS) azido functionalized diblock copolymers.

Figure 2 . 1 H 1 Figure 3 . 1 HFigure 4 .

 211314 Figure 2. 1 H NMR spectrum of PLA macroinitiator (2) in CDCl3.

Figure 5 . 1 HFigure 6 . 1 Figure 7 .

 51617 Figure 5. 1 H NMR spectrum of PLA126-b-P(S111-stat-4-AMS10) in CDCl3after functionalization with ptolylacetylene.

Table 1 .

 1 Molecular features of synthesized poly(D,L-lactic acid) macroinitiators.

	PLAn

a Conv. b ( %) Mn theor c (kg.mol -1 ) Mn NMR d (kg.mol -1 ) Mn SEC e (kg.mol -1 )

  n : number-average polymerization degree of PLA as determined by1 H NMR. b Conversion as determined by gravimetry. c Mn theor = conversion × DPn × M0 (Lactide). d Mn NMR: number-average molar mass as evaluated by1 H NMR. e Values from SEC/LLS measurements with PS standards. f End-group functionality as determined by1 H NMR.

						Đ e	F f
							(%)
	PLA126	91	7.2	8.2	9,300	1.54 97
	PLA167	93	14.0	14.8	12,300	1.50 96

a

Table 2 .

 2 Molecular features of synthesized PLAn-b-P(Sm-stat-4-AMSp) diblock copolymers. n, m, p : number-average polymerization degree of PLA and of P(S-stat-4-AMS) blocks as determined by1 H NMR. Mn theor = conversion × DPn × M0 (styrene)+ Mn PLA d Values from SEC/LLS measurements with PS standards.

	PLAn-b-P(Sm-stat-4-AMSp) a	Conv. b	Mn theor c	Mn SEC d	Đ d	XSt e	fPLA f
		(%)	(kg.mol -1 )	(kg.mol -1 )
	PLA126-b-P(S110-stat-4-AMS0)	98	19.8	20.2	1.12 1.00	0.18
	PLA126-b-P(S97-stat-4-AMS4)	92	20.2	19.9	1.51 0.96	0.40
	PLA126-b-P(S111-stat-4-AMS10)	92	20.5	22.3	1.35 0.91	0.36
	PLA167-b-P(S195-stat-4-AMS0)	90	37.1	32.8	1.21 1.00	0.33
	PLA167-b-P(S152-stat-4-AMS10)	88	37.7	28;3	1.38 0.93	0.38
	PLA167-b-P(S175-stat-4-AMS38)	93	38.3	36.5	1.59 0.82	0.30

a b Conversion as determined by gravimetry. c

Acknowledgments

The authors gratefully acknowledge financial support from the National Council of Science and Technology (CONACYT-México, grant #256727) as well as from CNRS and Univ Paris Est Creteil (France). They also thank Q. Jorge Felix Espinosa, M.Sc. J. Guadalupe Télles, and M.Sc. Maria del Rosario Rangel from CIQA for their technical assistance in the laboratory.