嵌段共聚物在软硬壁组成的受限空间中的诱导自组装行为的Monte Carlo 研究

The directed self-assembly of block copolymers in the confinement with soft and hard walls can be used to make advanced nanomaterial with complex structure and to study the phase behavior of block copolymer. Studying the influence of the confinement on the self-assembly of block copolymers is useful for tuning the morphology of aggregates and understanding the phase transition of copolymer, and the mechanism of phase transition. However, the relationship between shape of hard wall, the size of confinement and hard wall, the property of soft and hard walls, and the morphology and morphological transformation of the aggregate is unclear. In this project, we want to investigate the directed self-assembly of confined block copolymers by using the simulated annealing method based on the Monte Carlo method, to reveal the relationship between the shape, scale, and surface property of hard wall, the scale of confinement, the surface property of soft wall, and the morphology of aggregates, chain packing, configuration of block copolymer, to induct and clarify the role of the transition of the morphology, chain packing, configuration of block copolymer with varying these factors above, to help people to understand phase transition of copolymer and the mechanism of phase transition, and to provide indirection for effectively tuning the morphology of aggregates.

嵌段共聚物在软、硬受限壁共同组成的复杂受限空间中的诱导自组装行为不仅可用于制备具有复杂结构的多功能纳米材料，还有助于研究嵌段共聚物相行为。研究受限空间对嵌段共聚物自组装行为的诱导作用和影响，对于认识嵌段共聚物相转变规律及其机理，调控聚集体形貌结构具有重要意义。目前，对硬受限壁形状、受限空间和硬受限壁尺寸、受限壁表面性质等因素与聚集体形貌结构及其转变规律之间关系的认识还非常有限。本项目拟采用基于Monte Carlo method 的模拟退火方法研究嵌段共聚物在这种受限空间中的诱导自组装行为，揭示硬受限壁形状、受限空间和硬受限壁尺寸、受限壁性质与聚集体形貌结构、共聚物链构象及其堆砌方式之间的关系，归纳并阐明聚集体形貌结构、共聚物链构象及其堆砌方式随这些因素的转变规律，深入认识嵌段共聚物相转变规律及其机理， 为有效调控聚集体形貌结构提供依据。

嵌段共聚物粒子因其奇特形状和丰富内部结构，复合纳米粒子因其复杂分级结构和多功能性，在许多领域都有很大的潜在应用价值。嵌段共聚物在软硬受限壁共同组成的受限空间中的自组装是制备这两类粒子的有效途径。目前，对嵌段共聚物在复杂软受限空间中的自主组装形貌及其转变规律研究较少，认识有限。在本项目中，我们采用模拟退火方法研究AB两嵌段共聚物在圆柱、椭球、圆球外壳层中，圆筒、含一个底面圆筒，半球壳内部的自组装行为，AB两嵌段共聚物和C均聚物共混体系，ABC杂臂星型三嵌段共聚物在软受限条件下的自组装形貌。我们通过模拟计算获得具有丰富形貌的粒子，观察到众多形貌转变。模拟结果显示随着中性受限空间尺寸增大，结构从简单的部分体相逐渐变为复杂体相。随着圆柱、椭球、圆球的尺寸增大或者C均聚物含量增加，结构受其影响的范围和程度显著增强。增加圆柱长度和椭球长短轴比可显著改变结构的空间方向。层结构在上述各受限空间中具有完全不同的形状。软受限壁柔性与硬受限壁亲和性共同改变粒子形状和结构。C均聚物选择性可调控形状。软受限壁选择性可对粒子的结构和形状产生巨大影响。嵌段体积分数可通过改变结构影响形状。这些形貌和形貌转变规律及其机理拓展了相关知识，为准确调控嵌段共聚物粒子形貌，复合粒子结构和形状提供参考依据。为制备具有新颖形状和内部有序结构的嵌段共聚物粒子，和包含有机或无机粒子的复合粒子提供指导。