物理化学学报 >> 2007, Vol. 23 >> Issue (02): 139-144.doi: 10.1016/S1872-1508(07)60011-4

研究论文    下一篇

水溶液中Pluronic嵌段共聚物聚集行为的介观模拟

张秀青;苑世领;徐桂英;刘成卜   

  1. 山东大学胶体与界面化学教育部重点实验室, 济南 250100;山东大学理论化学研究所, 济南 250100
  • 收稿日期:2006-07-18 修回日期:2006-10-10 发布日期:2007-02-01
  • 通讯作者: 苑世领 E-mail:shilingyuan@sdu.edu.cn

Mesoscopic Simulation of the Phase Separation on Triblock Copolymer in Aqueous Solution

ZHANG Xiu-Qing;YUAN Shi-Ling;XU Gui-Ying;LIU Cheng-Bu   

  1. Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, Shandong University, Jinan 250100, P. R. China;Institute of Theoretical Chemistry, Shandong University, Jinan 250100, P. R. China
  • Received:2006-07-18 Revised:2006-10-10 Published:2007-02-01
  • Contact: YUAN Shi-Ling E-mail:shilingyuan@sdu.edu.cn

摘要: 通过介观动力学方法(MesoDyn)研究了低浓度下的三嵌段共聚物PEO27PPO61PEO27 (P104)水溶液的聚集行为, 讨论了聚合物浓度、模拟时间对P104水溶液相行为的影响. 在聚合物浓度较低(φ<35%)的情况下, 可以形成三种不同的胶束聚集体:球形胶束(spherical micelle)、胶束簇(micellar cluster)和盘状胶束(disk-like micelle). (1) 球形胶束(5%-10%, φ), 模拟的胶束结构表明疏水的PPO嵌段形成球形内核(micellar core), 而亲水的PEO嵌段形成核壳(micellar corona), 并有水分子存在内核和核壳之中;(2) 胶束簇(11%-15%, φ), 由于球形胶束之间的缔合, 形成直径明显高于球形胶束的聚集体, 其半径比球形胶束大1 nm左右;(3) 盘状胶束(16%-25%, φ), 胶束簇核壳PEO嵌段之间的相互缠绕, 形成了成串的类似盘状的胶束. 模拟中有序参数随浓度的变化证明了这种结构划分的合理性.

关键词: 嵌段共聚物, 介观模拟, 胶束

Abstract: The microphase separation dynamics of triblock copolymer surfactant [(ethylene oxide)27(propylene oxide)61-(ethylene oxide)27](P104) in aqueous solution was simulated by a dynamic variant of mean-field density functional theory for Gaussian chains. Different morphologies depending on the simulation concentration and time were shown in low concentration (φ<35%). With the increase of the concentration, the self-assemble aggregates changed from spherical micelles, micellar clusters, to disk-like micelles. (1) In the spherical micellar region (5%-10%, φ), the result of the simulation was similar to that of the experiment in that micelle was a dense core consisting mainly of PPO and a hydrated PEO swollen corona. (2) Due to the coalescence among spherical micelles, larger micellar clusters are formed in a concentration ranging from 11% to 15%(φ). (3) Owing to the attractions between the PEO coronas of micellar clusters, series of disk-like micelles were found above the concentration 16%(φ). The order parameters showed that the phase separation of spherical micelles was easily formed, while the micellar cluster or disk-like micelles required a longer time to acquire steady equilibrium.

Key words: block copolymer, Mesoscopic simulation, Micelle