Molecular Design and Synthesis of Amphiphilic Copolymers, and the Performances of Their Blend Membranes
两亲性共聚物的分子设计与合成及其共混膜性能

Based on molecular dsign,a series of amphiphilic compolymers with different molecular structures and morphologies were synthesized via various methods such as free radical polymerization,etherification,esterification,atomic transfer radical polymerization(ATRP) and reversible addition fragmentation chain transfer(RAFT) polymerization,etc.The synthesis process,reaction conditions,and mechanisms were studied in detail.The structures of the resultant copolymers (including graft,block,alternate and super-branched etc.) were characterized by spectroscopy,and their properties were examined.These amphiphilic copolymers have various morphologies,such as linear,comb-like,dumbbell-like,and chain-sphere-like etc.On basis of the structure characters of the amphiphilic copolymers and polymer membrane materials,the synthesized copolymers were selected and used as additives to prepare blend membranes.The effects of amphiphilic copolymers on membrane structure and properties were investigated detailedly.The hydrophobic chains in amphiphilic copolymers are generally miscible with special membrane materials,while hydrophilic chains provide the blend membranes with enhanced hydrophilicity and fouling resistance.The studied membrane materials in this work include poly(vinylidene fluoride) (PVDF),polyvinyl chloride (PVC),polysulfone (PSF),polyethersulfone (PES),poly(phthalazinone ether sulfone ketone) (PPESK) etc.The structures and properties of the blend membranes were controlled via tuning the thermodynamics and kinetics of membrane-forming systems.It was found that,during the course of membrane formation,amphiphilic copolymer additives accumulated spontaneously and self-organized on membrane surface.The coatings of amphiphilic copolymers on membrane surface promoted notably the hydrophilicity and anti-fouling ability of porous polymeric membranes.Based on these results,a new methodology for membrane modification that "surface modification is achieved by simple blending" was put forward.In addition,the functional groups in amphiphilic copolymers could endow the blend membranes with some special functions,such as biocompatibility,environmental responsivity,enzyme immobilization,etc.