基于混合液晶分子动力学模拟比较液晶分子旋转黏度大小

Rotational viscosity comparison of liquid crystals based on the molecular dynamics of mixtures

提高液晶波前校正器的响应速度是增加液晶自适应光学系统校正带宽的关键,而研究设计低旋转黏度的液晶分子是提高液晶波前校正器响应速度的根本方法.利用原子水平上的分子动力学方法获得了目标分子的液相、向列相以及近晶相,给出了理论计算液晶分子序参数以及旋转黏度的方法.与此同时,结合实验方法,提出利用混合液晶分子动力学模拟来比较液晶分子旋转黏度的大小,通过多次模拟、多起始点数据处理最大限度消除了因边界尺寸效应带来的数据波动,最后给出了两种高性能液晶分子的具体比较结果.这种分子动力学模拟方法能够探查分子结构细微差别对液晶相态以及旋转黏度的影响,为设计低旋转黏度的液晶分子提供了理论支持,必将为快速响应液晶材料的设计提供帮助.

It is critical to improve the response speed of a liquid crystal wavefront corrector in order to increase the band- width of a liquid crystal adaptive optics system. The design of liquid crystal molecules with small rotational viscosity becomes a basic method of increasing the response speed of a liquid crystal wavefront corrector. Various phases of liquid crystal from molecular dynamics simulation are given in this paper, and the detailed computational methods of order parameter and rotational viscosity are also presented. Rotational viscosities of liquid crystals are compared based on the molecular dynamics of mixtures. The data fluctuation is reduced effectively through several simulations and the multiple analysis of original data. A detailed process of molecular dynamics of mixtures is given in this paper and the result is greatly satisfactory. We believe that one can perform a better molecular design using this process and obtain a better understanding of molecular interactions of LCs.