PS-b-P4VP的合成及其薄膜的微相分离形貌

Synthesis of PS-b-P4VP and microphase separation morphology of its thin film

通过原子转移自由基聚合(ATRP)方法制备了聚苯乙烯-b-聚(4-乙烯基吡啶)二嵌段共聚物(PS-b-P4VP),使用核磁共振(1 H NMR)和凝胶渗透色谱(GPC)对嵌段共聚物进行了表征。将PS-b-P4VP/三氯甲烷溶液旋涂成膜,使用原子力显微镜(AFM)观察热处理条件对薄膜微相分离形貌的影响。结果表明,PS-b-P4VP薄膜会发生微相分离,形成以PS链段为分散相、P4VP链段为连续相基体的纳米尺度微相分离形貌。热处理条件的改变使薄膜呈现不同程度的微相分离形貌结构,提高热处理温度以及延长热处理时间均有利于促进嵌段共聚物的微相分离,使微相分离程度加大。在150℃、24h的热处理条件下,PS-b-P4VP薄膜形成了PS微相区以规则的柱状形态在薄膜表面突起的微相分离形貌,且分布均匀,界面清晰。

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 beingtreated 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.