Self-assembly of rod-coil-rod triblock copolymers: A route toward hierarchical liquid crystalline structures
Self-assembly of rod-coil-rod triblock copolymers: A route toward hierarchical liquid crystalline structures
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棒-线圈-棒三嵌段共聚物的自组装：通往分级液晶结构的途径
DOI：
10.1016/j.polymer.2016.09.028
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发表时间：
2016-10-26
期刊：
影响因子：
4.6
通讯作者：
Lin, Jiaping
中科院分区：
文献类型：
--
作者：
Li, Yongliang;Jiang, Tao;Lin, Jiaping
通过布朗动力学模拟研究了含有两种类型棒嵌段的棒-线圈-棒三嵌段共聚物的自组装行为。这些棒-卷-棒三嵌段共聚物能够自组装成具有层级的液晶（LC）结构。分级LC结构的形态可以通过温度、LC块的对称性和块长度来控制。随着温度的降低，观察到从各向同性层状向近晶C层状的转变，伴随着棒块的取向有序和倾斜角的增加。对于由对称嵌段共聚物形成的分层层状结构，存在两个具有几乎相同的有序和倾斜角的两个棒嵌段的LC相。而对于不对称嵌段共聚物形成的层状结构，两个液晶相呈现两种不同的长度尺度，具有不同的有序度和倾斜角。通过调整线圈和棒块的长度，在块长度与温度的空间中绘制出结构的稳定区域。研究结果为深入理解棒状-线团-棒状三嵌段共聚物的自组装行为和设计分级液晶结构提供了有用的信息。(C)2016爱思唯尔有限公司版权所有。
Brownian dynamics simulations are performed to investigate self-assembly behavior of rod-coil-rod triblock copolymers that contain two types of rod blocks. These rod-coil-rod triblock copolymers are capable of self-assembling into liquid crystalline (LC) structures with hierarchy. The morphologies of the hierarchical LC structures can be controlled by temperature, symmetry of LC blocks, and block length. As the temperature decreases, a transition from isotropic lamellae to smectic C lamellae is observed, accompanied by an increase in orientational ordering and tilt angle of rod blocks. For the hierarchical lamellae-in-lamella structures formed by symmetric block copolymers, there are two LC phases with nearly identical ordering and tilt angle for two rod blocks. While for the lamellae-in-lamellae formed by asymmetric block copolymers, the two LC phases exhibit two different length scales with diverse ordering degrees and tilt angles. By adjusting the lengths of coil and rod blocks, the stability regions of the structures are mapped out in space of the block length versus the temperature. The findings in the present work could provide useful information for understanding the self-assembly behavior of rod-coil-rod triblock copolymers and designing hierarchical liquid crystalline structures. (C) 2016 Elsevier Ltd. All rights reserved.