层状二嵌段共聚物与纳米棒共混体系的自组装

Self-assembly of mixtures of two diblock copolymers and nanorods

采用耗散粒子动力学(DPD)方法研究了层状二嵌段共聚物与纳米棒共混体系的自组装行为.系统地考虑了棒的粒子数比、长度及棒与高分子间的相互作用等因素对混合体系自组装的影响.一系列的构型及相转变都是在共聚物的相分离与纳米棒的聚集相行为共同作用下的结果.当把纳米棒掺入到高分子体系时,从熵和焓的角度可以更本质地理解共混体系的自组装,尤其是棒的相行为.从焓方面,纳米棒与各高分子链段间相互作用决定了棒的分布;从熵方面,棒的各向异性、相区域的空间约束及高分子链的构象熵共同决定了棒的取向.

The self-assembled phase behaviors of lamellar block copolymers and nanorods mixtures were investigated by dissipative particle dynamics(DPD) simulations.A series of parameters,such as nanorod concentration,length,and the polymer-nanorod interaction,are introduced to analyze the cooperative phase behavior and novel morphologies of hybrids.The final phase structures of the mixtures result from the mutual inducement between mesophase-forming copolymers and nanorods aggregates.When nanorods are mixed into the polymer fluids,it is used for understanding the intrinsic characteristics of the composite self-assembly by considering the enthalpic and entropic interactions,especially for the rods' phase behaviors.The nanorods distributions reveal a degree of enthalpically driven self-assembly,due to the interactions among species.The nanorods' orientation show a degree of entropically generated self-assembly,based on the competition among the inherent shape anisotropy of nanorods,confinement of host phase separated domains,and the conformational entropy of chains.