This thesis focuses on the development of new stationary phases for use in hydrophilic interaction liquid chromatography using TRIS-based and phosphorylcholine typed monomers and porous silica particles as starting substrates. In this thesis, several ways of polymerizing highly hydrophilic mono­mers onto pore surfaces of silica supports are described, based on several “grafting from” schemes. “Controlled/living” radical polymerizations including atom transfer radical polymerization (ATRP) and iniferter-mediated polymerization in conjunction with conventional free radical polymerization are demonstrated to be successful tools for grafting different hydrophilic monomers (polyhydroxyl and phosphorylcholine [meth]acrylamide/acrylates) onto the silica surfaces. Reaction solvents are proven to play an essential role to achieve efficient graft polymerization of activated silica surfaces with these amphiphilic vinylic monomers, which is difficult because of their restricted access to the activated surface in solvents that can be used because of solubility constraints. Two tentacle TRIS-based polymer grafted silica, namely TRIS-WAX – TRIS functionality bonded to silica via a C–N–C imine bond and TRIS-Amide – TRIS bonded to silica via an amide bond, prove to be useful as stationary phases for hydrophilic interaction chromatography (HILIC).The TRIS-WAX exhibits a mixed mode hydrophilic partitioning and weak anion exchange (HILIC/WAX) retention mechanism while retention by hydrophilic partitioning is the dominant mechanism on the neutral TRIS-Amide phase which lacks weak anion exchange (WAX) properties. Interestingly, both these phases have selectivities that are radically different from most commercial HILIC stationary phases. Finally, a method is demonstrated for synthesizing a stratified (graft-copolymerized) silica material based on N,N′-methylenebisacrylamide and 2-methacryloyloxyethyl phosphorylcholine (MPC) using a “controlled/living” photoiniferter-mediated polymerization from the N,N-diethyldithiocarbamate iniferter moiety immobilized silica surfaces. This polymerization method proves to be successful for graft-blockcopolymerization of different highly hydrophilic monomers onto the activated surfaces of porous silica. In this way, silica surfaces are grafted with a cross-linked amide-based hydrogel, on top of which a tentacle zwitterionic phosphorylcholine-typed layer is synthesized. The resulted material proves to be useful for HILIC separations and possesses different selectivity for the tested organic acids compared to that of commercial ZIC-cHILIC stationary phase.

L’objectif principal de ce travail de thèse est de synthétiser par polymérisation RAFT en milieux homogène et hétérogène des copolymères à blocs amphiphiles de structure bien contrôlée. Un procédé simplifié, « ont pot » a donc été développé pour synthétiser ces copolymères et les auto-assembler en particules dans l’eau. Cette méthode dite de « l’auto-assemblage induit par la polymérisation » (PISA) permet de synthétiser en quantité des copolymères à blocs amphiphiles en milieux aqueux sans aucune étape de purification intermédiaire. Dans ce procédé, deux étapes successives sont effectuées dans le même réacteur. La 1ère étape a pour but de synthétiser des agents RAFT macromoléculaires hydrophiles (macroRAFTs) par polymérisation en solution dans l’eau. Ces macroRAFTs fonctionnalisés par un groupement trithiocarbonate sont ensuite utilisés dans le même réacteur comme agents de contrôle etprécurseurs de stabilisants pour la polymérisation en émulsion du monomère hydrophobe directement dans l’eau. Lors de cette 2nde étape, des copolymères à blocs amphiphiles sont formés et s’auto-assemblent sous forme de particules aux morphologies variées (sphères, filaments et vésicules). Nous avons alors étudiés les différents paramètres (pH, température de polymérisation en émulsion, nature des monomères hydrophobe et hydrophile, taux de solide, masses molaires des blocs hydrophobe et hydrophile, etc)gouvernant la formation de morphologies spécifiques. Un objectif supplémentaire a été l’étude du comportement viscoélastique linéaire des suspensions de ces nano-fibres polymère à une température inférieure (25°C) ou supérieure (130°C) à la température de transition vitreuse (Tg) du coeur polystyrène des nano-fibres. A T < Tg, les nano-fibres sont parfaitement rigides et obéissent à une dynamique brownienne de bâtonnets. En effet, les lois d’échelles déduites du comportement viscoélastique de ces suspensions obéissent aux lois prédites par Doi-Edwards. En revanche, ces nano-fibres sont flexibles pour T > Tg et ont une dynamique Brownienne de chaînes polymères en solution. / The aim of this work was synthesis of well-defined amphiphilic block copolymers in homogenous and heterogenous media using RAFT polymerization (Reversible Addition-Fragmentation Chain Transfer) and to study their self-assemblies in water. A one-pot process in water was developed for the synthesis of amphiphilic block copolymers that simultaneously to their growth self-assembled into nano-particles. This method called “polymerization-induced self-assembly” (PISA) allows the synthesis of large quantities of amphiphilic block copolymers in aqueous media without any intermediate purification step. During this process, two successive polymerization steps are performed in the same reactor. The first step consists in the synthesis of the hydrophilic macromolecular RAFT agents (macroRAFT agents) possessing a trithiocarbonate reactive group via RAFT in water. Without purification, these macroRAFT agents are reactivated for the polymerization of a hydrophobic monomer in the same reactor via RAFT emulsion polymerization. The resulting amphiphilic block copolymers self-assembled into nano-objects with various morphologies (spherical micelles, nanofibers and vesicles). Different parameters (pH, temperature, natureof hydrophilic and hydrophobic monomers, solids contents, molar masse of hydrophilic and hydrophobic blocks, etc) control these morphologies. Besides, the viscoelastic properties of polymeric nanofibers suspensions were studied as a function of the temperature. Below the Tg of polystyrene core at 25°C, the scaling law from viscoelastic behavior of these nanofiber suspensions the Doi−Edwards theory on the Brownian dynamics of rigid rods. Above Tg at 130°C, the nanofibers are flexible and it observed that their dynamics obey the power laws for polymer chains in solution.