Hierarchical elasticity of bimesogenic liquid crystals with twist-bend nematic phase
Hierarchical elasticity of bimesogenic liquid crystals with twist-bend nematic phase
复制标题
扭转弯曲向列相双介晶液晶的分级弹性
DOI：
10.1063/1.4919065
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发表时间：
2015
影响因子：
4
通讯作者：
Jang
中科院分区：
文献类型：
--
作者：
Chang;M. R. Vengatesan;J. Vij;Jang
早在2001年，Dozov就预测在K33 - 2时扭弯向列相可以自发形成，而这一相最近也在双子星中被发现。为了验证Dozov的假设，我们结合扭曲向列相和面内开关电池的fredericksz阈值方法，精确测量了CB7CB在向列相和扭转-弯曲向列相的整个温度范围内的弹性常数与温度的依赖关系。在整个相变过程中观察到K22和K33的异常变化。向列相高温区数据外推估计的弹性似乎完全满足Dozov的假设，但相变附近的弹性数据表现出相反的趋势。这可以用层次系统的一般性质来解释，其中宏观弹性主要由更高层次结构的扭曲所控制。
In 2001, Dozov predicted that twist-bend nematic phase can be spontaneously formed when K33 2, and this phase has recently been discovered in bimesogens. To verify Dozov's hypothesis, we have measured precisely the temperature dependence of the elastic constants of CB7CB in the entire temperature range of nematic phase and in twist-bend nematic phase close to the transition temperature by combing the Freedericksz threshold methods for a twist nematic and an in-plane switching cells. Anomalous changes in K22 and K33 are observed across the phase transition. The elasticity estimated via extrapolation of the data in the high temperature region of the nematic phase seems to fully satisfy Dozov's hypothesis although the elasticity data in the vicinity of the phase transition exhibit opposite trends. This can be explained by the general nature of a hierarchical system where the macroscopic elasticity is governed mostly by the distortion of a higher level structure.