Abstract:

The mesoscopic phase of block copolymers PAn-PEG-PAn in aqueous solution was investigated by dissipative particle dynamics (DPD) simulation.The effects of the molar fraction of PAn segment in the copolymers and its concentration on the copolymers’ self-assembling were discussed.The distribution of PEG and PAn segments on the surface of the spherical micelle of the copolymer was interesting but was difficult to observe by experiments.The authors focused on investigating the characteristics of the spherical micelle of the copolymers in a low concentration.There existed two novel core-shell spherical micelles separately with increasing molar fraction of the PAn segment.One was that the PAn segment made up the shell and the PEG segments the core; the other was that the PEG segments made up the shell and the PAn segments the core.A greater part of water was aggregated to form cylindrical and spherical micelles, while the remaining was distributed in the block copolymers symmetrically when the mass fraction of the copolymers was more than 66.7%.DPD simulation could be considered as an assistant for the experimental research and could provide useful information which is difficult to obtain by experiments.

Key words:

耗散粒子动力学, 自组装, 聚苯胺, 聚乙二醇

摘要： 用耗散颗粒动力学(DPD)模拟了嵌段共聚物PAn-PEG-PAn在水溶液中的介观相分离。考察了浓度和嵌段比对嵌段共聚物自组装影响的规律，获得了实验难以观察到的介观层次上各嵌段在球面分布情况，并重点研究了嵌段共聚物在稀溶液中自组装成球体的特征和原理。随着PAn链段的摩尔分数的增加，模拟先后获得三种球体，一是憎水段PAn为外壳、亲水段PEG为内核的球体；二是中心为亲水段PEG，中间层为憎水段PAn，最外层是亲水段PEG的三层壳核型球体；三是以亲水段PEG为外壳、憎水段PAn为内核的球体。在高浓度下，水在体系中呈现出有趣的分布现象，即水大部分聚集呈柱状或球状，少部分均匀分散在嵌段共聚物中。结论对实验可以起辅助和指导作用。

关键词:

耗散粒子动力学, 自组装, 聚苯胺, 聚乙二醇