Coil-rod-coil刚柔嵌段共聚物在选择性溶剂中的自组装  

Self-assenbly Behavior of Coil-rod-coil Triblock Copolymers in Selective Solvents

作　　者：陈增磊 何林李[1] 

机构地区：[1]温州大学物理与电子信息工程学院,温州325035

出　　处：《高分子学报》2014年第4期514-522,共9页Acta Polymerica Sinica

基　　金：国家自然科学基金(基金号21104060)资助项目

摘　　要：采用耗散粒子动力学方法(dissipative particle dynamics,DPD)研究了coil-rod-coil(CRC)三嵌段刚柔共聚物在选择性溶剂中的自组装.在链选择性溶剂中,刚性棒长Lr与柔性链长Lc都影响着CRC溶液的自组装及相转变.随Lr的增大,棒与溶剂的接触面变大界面能升高,为减小体系的自由能,棒嵌段趋向聚集以减少接触面与界面能.随Lc的增大,链的自由伸展构象熵增大,影响着棒嵌段聚集体结构的形成,使棒嵌段的分布更加分散.在研究溶剂性质aCS与棒长Lr对体系自组装影响的情况中,观察到两类有趣的相结构:球形相和胶束相.随着参数aCS从亲链变为中性再到亲棒,在球形相内部,不仅棒相区由球体内部移向球表面,而且棒相区与链相区的层次分布也发生了明显地变化.同样,Lr的改变也影响着球形相内部相区的分布,同时诱导了不同球形相间的构型转变.胶束相包括分段胶束和螺旋胶束两种,形成于棒长较长的情况,胶束相中棒嵌段的排列呈现出明显的液晶相结构.Dissipative particle dynamics are used to investigate the self-assembly behavior of coil-rod-coil （CRC） tribloek copolymers in selective solvents. In coil-selective solvent case,the morphological transitions of CRC solutions are induced by varying the rod length Lr and the coil length Lc. The increase of rod length makes the contact area between rods and solvents larger, and the interface energy enhanced. To reduce the contact area and interface energy, rod blocks tend toward aggregation. With increasing coil length, the coil stretching conformational entropy is increased,which results in the distribution of rod block aggregates more scattered. Two kinds of interesting phase structures （spherical phase and micellar phase） are observed by varying the solvent preference （acs） and rod length Lr. With the solvent preference acs varied from coil-selective to neutral and then to rod-selective,the rod-rich-domains in spherical micelle move from the interior to the surface and the number of rod-rich-domain layers is changed. Also, the rod length influences the internal structure of the spherical phase and induces the phase transition between the different spherical phases. The micellar phase includes segmented smectic micelle and rod helices-like micelle, where the rod blocks are arranged in the liquid crystal structure due to the anisotropy of the long rods.

关 键 词：耗散粒子动力学 Coil—Rod COIL 选择性溶剂 自组装 界面能 

分 类 号：O631.3[理学—高分子化学]