淬火和退火对称三嵌段共聚物薄膜形貌和结构的Monte Carlo模拟

A Monte Carlo Simulation of Morphology and Structure for Thin Films of Symmetric Triblock Copolymer after Quenching and Annealing

嵌段共聚物薄膜淬火形貌与初始化时嵌段共聚物熔体的状态相关 ,淬火得到的有序形貌有时存在缺陷 ,而退火则可以消除这些缺陷形成更规整的层状结构 ,且退火得到的嵌段共聚物分子的均方回转半径等都小于淬火得到的 .与淬火比较 ,退火使高分子链充分松弛 ,增加了薄膜中有利于提高材料物理力学性能的桥键含量 .不同于受限自由表面间的对称二嵌段共聚物首先在表面区域形成有序结构 。

Self-assembly thin films of symmetric triblock copolymer after annealing and quenching were examined by an effective Monte Carlo simulation method. The defects in the ordered lamellae of the thin films after quenching,which were dependent on the initialization of copolymer melts,are removed in the thin films after annealing. The mean-square gyration radius and end-to-end distance of copolymer chains in the thin films after annealing are smaller than those in the thin films after quenching because of the complete relaxation of polymer during annealing. We also find that the density of A block in the region near to the surface is higher than that in the interior of the thin films. As a result,it is different from the thin films of symmetric A n B n diblock copolymer,in which surface ordering forms before the interior,that ordering phenomena occurs first in the interior region in the thin films of symmetric A n B m A n triblocl copolymer.