Song Jianhui, Shi Tongfei, Li Yunqi, Chen Jizhong, An Lijia
State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China.
J Chem Phys. 2008 Aug 7;129(5):054906. doi: 10.1063/1.2957463.
The phase behavior of symmetric ABA triblock copolymers containing a semiflexible midblock is studied by lattice Monte Carlo simulation. As the midblock evolves from a fully flexible state to a semiflexible state in terms of increase in its persistence length, different phase behaviors are observed while cooling the system from an infinite high temperature to a temperature below T(ODT) (order-disorder transition temperature). Within the midblock flexibility range we studied (l(p)N(c)<or=0.105), a lamellar structure is formed at equilibrium state as the situation for fully flexible chains. The fraction of bridge chain is evaluated for the lamellar structures. We find that the increase in midblock rigidity indeed results in the increase in bridge chain fraction within the range from 44.9% to 51.8%. In order to elucidate phase behavior evolution observed in our simulation, a detailed conformation distribution analysis is also given. Our results bridge a gap of different phase behaviors between rod-coil block copolymer and coil-coil block copolymer and show a necessity to investigate rigidity influence on phase diagram.
通过晶格蒙特卡罗模拟研究了含有半柔性中间嵌段的对称ABA三嵌段共聚物的相行为。随着中间嵌段的持久长度增加，从完全柔性状态演变为半柔性状态，在将系统从无限高温冷却至低于T(ODT)（有序-无序转变温度）的温度时，观察到不同的相行为。在我们研究的中间嵌段柔性范围内（l(p)N(c)≤0.105），与完全柔性链的情况一样，在平衡状态下形成了层状结构。对层状结构的桥链分数进行了评估。我们发现，在44.9%至51.8%的范围内，中间嵌段刚性的增加确实导致桥链分数增加。为了阐明我们模拟中观察到的相行为演变，还给出了详细的构象分布分析。我们的结果填补了棒-线团嵌段共聚物和线团-线团嵌段共聚物之间不同相行为的差距，并表明有必要研究刚性对相图的影响。
