对称三嵌段共聚物ABA在软受限条件下的自组装行为

Self-assembly behavior of symmetric triblock copolymer ABA under soft confinement

为了探究对称三嵌段共聚物ABA在不良溶剂中的自组装行为,采用模拟退火方法研究了共聚物的体积分数、共聚物与溶剂的相互作用以及溶液的浓度对自组装聚合体结构的影响.模拟结果表明:嵌段共聚物的体积分数以及共聚物与溶剂的相互作用共同决定了聚合体的形貌.当嵌段共聚物处于中性或弱选择性溶剂中时,对聚合体的形貌起主导作用的是嵌段共聚物的体积分数;当嵌段共聚物处于强选择性溶剂中时,嵌段共聚物与溶剂的相互作用决定了聚合体的形貌.当溶剂对共聚物的选择性足够强时,在特定的溶液浓度下,聚合体具有单螺旋状、双螺旋状和堆叠圆环状等多个简并结构.随着溶液浓度的增加,聚合体的外部形貌由椭球状过渡到近球状,内部结构的变化顺序依次为圆盘结构、螺旋结构和多重简并结构.

In order to investigate the self-assembly behavior of symmetric triblock copolymer ABA in the poor solvent,the effects of volume fraction of copolymer,interaction of copolymer and solvent and the concentration of the solution on the structure of self-assembly polymer were studied using simulated annealing technique.The simulation results show that the morphology of polymer is determined by the volume fraction of block copolymer and the interaction of copolymer and solvent.When the block copolymer is in a neutral or weakly selective solvent,the bulk fraction of block copolymer plays a dominant role in the polymer morphology.When the block copolymer is in a highly selective solvent,the interaction of block copolymer and solvent determines the mor-phology of the polymer.When the selectivity of solvent to the copolymer is strong enough,the polymer has multiple degeneracy structures such as single helix,double helix,stacked circle with a given solution concentration.The external morphology of the polymer changes from ellipsoidal to near-spherical with the increase of solution concentration,and the order of the internal structure changes are disk structure,spiral structure and degenerate structure.