Lomonosov Moscow State University, Faculty of Physics, Moscow 119991, Russia.
Kirensky Institute of Physics, Federal Research Center - Krasnoyarsk Scientific Center, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk 660036, Russia.
Phys Rev E. 2017 Nov;96(5-1):052701. doi: 10.1103/PhysRevE.96.052701. Epub 2017 Nov 6.
Polymer-dispersed liquid crystal composites have been a focus of study for a long time for their unique electro-optical properties and manufacturing by "bottom-up" techniques at large scales. In this paper, nematic liquid crystal oblate droplets with conical boundary conditions (CBCs) under the action of electric field were studied by computer simulations and polarized optical microscopy. Droplets with CBCs were shown to prefer an axial-bipolar structure, which combines a pair of boojums and circular disclinations on a surface. In contrast to droplets with degenerate planar boundary conditions (PBCs), hybridization of the two structure types in droplets with CBCs leads to a two-minima energy profile, resulting in an abrupt structure transition and bistable behavior of the system. The nature of the low-energy barrier in droplets with CBCs makes it highly sensitive to external stimuli, such as electric or magnetic fields, temperature, and light. In particular, the value of the electric field of the structure reorientation in droplets with CBCs was found to be a few times smaller than the one for droplets with PBCs, and the droplet state remained stable after switching off the voltage.
聚合物分散液晶复合材料因其独特的电光性能以及通过“自下而上”技术在大规模生产而长期以来一直是研究的焦点。本文通过计算机模拟和偏振光学显微镜研究了在电场作用下具有锥形边界条件（CBCs）的向列相液晶扁滴。结果表明，具有 CBCs 的液滴倾向于形成轴向双极结构，该结构在表面上结合了一对 boojums 和圆形的位错。与具有简并面内边界条件（PBCs）的液滴相比，CBCs 液滴中两种结构类型的混合导致了双势阱能量分布，从而导致了系统的突然结构转变和双稳态行为。CBCs 液滴中低能势垒的性质使其对外部刺激（如电场或磁场、温度和光）高度敏感。特别是，发现 CBCs 液滴中结构重取向的电场值比 PBCs 液滴中的小几倍，并且在关闭电压后液滴状态仍然稳定。
