含无规共聚组分的两嵌段聚合物A-b-(B-r-C)的合成以及自组装

通过原子转移自由基(ATRP)方法合成了其中一个嵌段是由2种单体无规共聚的两嵌段聚合物——聚丙烯酸肉桂酸乙酯-b-(聚苯乙烯-r-聚丙烯酸叔丁酯),(记为PCEA-b-(PtBA-r-PS)).讨论了聚合过程中影响分子量分布以及分子量控制的各种因素.通过氢核磁(1H-NMR)确定各嵌段的重复单元数分别为50,111,138.通过透射电镜(TEM)观察,研究了该嵌段聚合物在选择性溶剂1-氯癸烷以及环戊烷中的自组装行为,发现该嵌段聚合物在环己烷中直接分散可以形成有聚集倾向的短棒状或球形胶束,而在1-氯癸烷中直接分散得到的胶束,在膜表面随着1-氯癸烷溶剂的缓慢挥发可以组装得到具有规则微纳结构的相互连接的柱状胶束.

SYNTHESIS AND SELF-ASSEMBLY BEHAVIORS OF BLOCK COPOLYMER A-b-(B-r-C) BEARING RANDOM COMPONENTS

A block copolymer,poly(2-cinnamoyloxyethyl acrylate)-block-poly(tert-butyl acrylate)-ran-(styrene)](PCEA-b-P(tBA-r-St)),was synthesized by ATRP.Some factors,such as solvents,monomer concentration,and the reserved ratio of end initiating groups after the preparation of the first block influencing the PDI and the control of molecular weight in the synthetic process were discussed.Acetonitrile was found as one of the most suitable solvent in using ATRP to synthesize poly(2-trimethylsilyloxyethyl acrylate)(PHEA-TMS) due to the outstanding controlling of the polymer’s molecular weight distribution as low as close to monodisperse.The structure of the prepared diblock copolymer was confirmed as PCEA53-b-(PtBA111-r-PS138) with 1H-NMR analysis.It shows a narrow distribution of molecular weight of 1.18 determined by GPC method.This diblock copolymer can be dispersed directly in some selective solvents,such as 1-chlorodecane and cyclopentane,to form the micelles.It was investigated by TEM that a unique aggregated-cylinder structure was formed by the self-assembly of the block polymer in 1-chlorodecane following slow evaporation of the solvent because 1-chlorodecane has a very high boiling point of 223℃.While in cyclopentane which has a much lower boiling point of 49.3℃,due to the quick volatilization of solvent the block copolymer only self assembled into some short rodlike micelles.