Investigating nucleation of phase transitions in rod-coil block copolymers
Investigating nucleation of phase transitions in rod-coil block copolymers
复制标题
研究棒-线圈嵌段共聚物中相变的成核
DOI：
10.1016/j.polymer.2020.122960
复制
发表时间：
2020
期刊：
影响因子：
4.6
通讯作者：
Ping Tang
中科院分区：
文献类型：
--
作者：
Jingyu Shao;Yuliang Yang;Ping Tang
液晶聚合物的成核与取向相互作用可以降低聚合物结晶过程中的能垒。在本工作中，我们将联合收割机和弦方法结合起来研究了棒状-卷曲嵌段共聚物的成核和液晶行为。通过考察不同方向的圆柱体到层流的成核跃迁，首次获得了临界核的体积、形状和能垒等信息。我们进一步研究了取向相互作用沿沿着不同的过渡路径的影响。结果表明，当圆柱体和薄片体的方向不一致时，形核过程中的过渡路径较长，且会发生多次再取向，从而导致较高的能垒。研究了不同Flory-Huggins相互作用下的成核以及通过介稳结构的成核，并与经典成核理论进行了比较。本工作发展了具有链段取向的复杂嵌段共聚物的成核研究，有助于理解液晶聚合物的成核过程。
It is known that the nucleation of liquid crystal polymers with orientation interactions can reduce the energy barrier during the polymer crystallization. In this work, we combine the SCFT and string method to explore the nucleation and liquid crystal behavior of rod-coil block copolymers. By examining nucleation transitions from cylinders with different directions to lamellae, we obtain the information of critical nuclei for the first time, including the volume, shape and energy barrier. We further investigate the impacts of orientation interactions along different transition paths. The results show that if the cylinder and lamellae have inconsistent directions, the nucleation will occur with relatively longer transition path and multiple reorientations, and thus leading to higher energy barrier. Nucleation under different Flory-Huggins interactions and nucleation via precursory metastable structures are investigated, and compared with the classical nucleation theory. This work develops the nucleation studies for complex block copolymers with segment orientations, which is helpful for understanding the nucleation of liquid crystal polymers.