PS-b-P4VP两嵌段共聚物的合成及其自组装的研究

SYNTHESIS AND SELF-ASSEMBLY OF (STYRENE-4-VINYL PYRIDINE) BLOCK COPOLYMERS

双硫酯 (PhC(S)SCH2 Ph)作为链转移剂 ,AIBN作为引发剂 ,用可逆的加成 断裂链转移 (RAFT)活性自由基聚合方法 ,合成了PS大分子链转移剂 .然后在AIBN引发下 ,利用制得的大分子链转移剂 ,以DMF为溶剂 ,80℃下采用RAFT方法 ,合成了PS b P4VP两嵌段共聚物 ,通过核磁共振谱及动力学的研究证明了其活性聚合的特征 .结果表明聚合反应在 2 4h内转化率可达 95 % .并用透射电子显微镜 (TEM )和扫描电子显微镜(SEM)研究了PS b P4VP两嵌段共聚物在选择性溶剂硝基苯 四氢呋喃中的自组装行为 ,研究结果表明改变聚合物的浓度以及选择性溶剂 ,可观察到自组装行为的变化 .

Polystyrene ( PS ) was obtained by reversible addition-fragmentation chain transfer ( RAFT ) polymerization, using benzyl dithiobenzoate, (PhC ( S ) SCHPh ), as transfer agent, AIBN as initiator. A amphiphilic copolymer, P( styrene-b-4-vinyl pyridine) ( PS-b-P4VP ) was prepared by using PS as macro-chain transfer agent and AIBN as initiator via the RAFT mechanism. Its structure was obtained by H-1-NMR analysis. The conversion can reach almost 95 % within 24 h. Its structure was characterized by H-1-NMR studies. The results. showed that the molecular weight of the copolymer increased linearly with the increasing of conversion, and the living nature of the polymerization was revealed. Self-assembly of this amphiphilic block copolymer in different selective solvents was also studied by using transmission electron microscopy ( TEM ) and scanning electron microscopy ( SEM ). The results showed that core shell microspheres were formed with P4VP block as the core and PS block as the shell in the nitrobenzene/THF solvent. The size of particles increased with the increasing of the concentration of the block copolymer. The size and shape of the particles were also changed with the type of the solvent and concentration.