Wensink H H
Institut für Theoretische Physik, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, D-40225, Düsseldorf, Germany.
J Chem Phys. 2007 May 21;126(19):194901. doi: 10.1063/1.2730819.
We study the stability of inhomogeneous liquid crystalline states in systems of monodisperse, stiff, charged rods. By means of a bifurcation analysis applied to the Onsager free energy for charged rods in strongly nematic states, we investigate nematic-smectic and nematic-columnar instabilities as a function of the Debye screening length kappa(-1). While the nematic-smectic transition clearly preempts the nematic-columnar one in the regime of strong screening (i.e., small kappa(-1)) a marked stability of hexagonal columnar order is observed at larger screening lengths. The theoretical results are substantiated by Brownian dynamics computer simulation results based on the Yukawa site model. Our findings connect to experiments on tobacco mosaic virus rods, in particular, but might be relevant for soft rodlike mesogens in strong external directional fields in general.
我们研究了单分散、刚性、带电棒状体系中不均匀液晶态的稳定性。通过对强向列态下带电棒的昂萨格自由能进行分岔分析，我们研究了向列 - 近晶相和向列 - 柱状相不稳定性作为德拜屏蔽长度κ⁻¹的函数。在强屏蔽 regime（即小κ⁻¹）中，向列 - 近晶相转变明显先于向列 - 柱状相转变，而在较大屏蔽长度时观察到六方柱状相序有显著的稳定性。基于 Yukawa 位点模型的布朗动力学计算机模拟结果证实了理论结果。我们的发现尤其与烟草花叶病毒棒状粒子的实验相关，但一般来说可能与处于强外部定向场中的软棒状介晶有关。
