Double Stimuli-Responsive Porous Mem- branes from Polystyrene-block-poly(N,N- dimethyl-aminoethyl methacrylate) Diblock Copolymers

摘要

Block copolymers represent an ambitious class of materials as their scope of applicability is still rising. Mostly,this is due to their inimi- table self-assembling properties,rendering them suitable for applica- tions in solution,in thin films1 or as components of porous composite membranes.2 Also in the field of industrially important membrane pro- duction processes,in particular via controlled phase separation ("phase-inversion") of polymer solutions,block copolymers are becom- ing more and more popular. This is mainly attributed to the constantly increasing number of processes in which the desired separation prob- lem cannot be solved with state-of-the-art membranes3. One of the key features of block copolymers is the facile implementation of "smart" materials,containing compartments with the ability to change confor- mation or properties upon application of environmental stimuli like pH,temperature or light4. Non-solvent-induced phase separation (NIPS) is the most important industrial process for the fabrication of "asymmetric" membranes,having a very thin "skin" layer supported by a macropor- ous substructure.5 Recently,this process has been applied for the first time to well-defined block copolymers,polystyrene-block-poly(4- vinylpyridine) (PS-b-P4VP).6 However,the reported procedures yield membranes which can react to a single stimulus only.