关键词: PS-b-P4VP, ATRP, 薄膜, 微相分离形貌, 热处理

Abstract: Self-assembly in thin films of block copolymer of polystyrene and poly(4-vinylpyridine) （PS-b-P4VP）derived by the immiscibility between the constituted blocks could create rich morphologies with nanometer scale periodic patterns over large areas,leading to potential applications in nanotemplates,nanopatterns,and selective separation membrance with well-defined channel size.The microphase separation behavior and the resulting morphological structure have attracted more attention from investigators.In this paper,diblock copolymer of PS-b-P4VP was synthesized using atom transfer radical polymerization(ATRP) and its structure was characterized by 1H NMR and GPC.The block copolymer was dissolved in chloroform and PS-b-P4VP thin film was prepared by spin coating.Atomic force microscope(AFM) was used to observe the microphase separation morphologies of PS-b-P4VP thin films obtained under different conditions of heat treatment.It was found that microphase separation occurred in PS-b-P4VP film,generating nanoscale microphase separation morphology with PS microphase as dispersion phase and P4VP as continuous phase matrix.The film exhibited different microphase separation morphologies under different heat treatment conditions.Increasing temperature and/or prolonging time in the heat treatment process of PS-b-P4VP film accelerated the microphase separation in the film.After being treated at 150℃ for 24 h,PS-b-P4VP film demonstrated a microphase separation morphology with column-shaped PS microphases projecting from the P4VP matrix.The column-shaped PS microphases were uniformly distributed on the surface of the film and the interface was clear.

Key words: PS-b-P4VP, ATRP, thin film, microphase separation morphology, heat treatment