Charge mosaic membranes: Microdomain fixing of (polystyrene–poly‐4‐vinylpyridine) sequential copolymers prepared by macromonomer methods

Polystyrene (PST) macromonomers having several allyl groups at the ends were synthesized by the mechanical scission reaction of the main chain in the presence of diallylmalonic acid diethyl ester (DAME). Photosensitive benzophenone groups were introduced on a PST macromonomer molecule by the reaction of these PST macromonomers with benzoyl chloride. The palm‐treelike (PST–poly‐4‐vinylpyridine (P4VP)) sequential copolymers with different compositions were prepared by the radical copolymerization of PST macromonomer with 4VP. The morphological observation of these sequential copolymers was carried out by the transmission electron microscopy. The PST block microdomains were fixed by photocrosslinks (UV irradiation) in the presence of mono‐ and bifunctional unsaturated compounds in the state of mesomorphic structures. The microdomain fixing of P4VP blocks was carried out by using the vapor of 1, 4‐dibromobutane (DBB). After subsequent chemical modifications (quaternization of residual P4VP blocks and sulfonation of PST blocks), the effect of microdomain fixings was elucidated from the moisture content of positive and negative regions. These results are discussed in some detail.