Temperature dependence of dynamic response of liquid crystal materials

Most properties of liquid crystal (LC) materials will change with the change of temperature, which makes the performance of liquid crystal display (LCD) and other devices change. However, at low temperature, the properties of LC will mutate with the decrease of temperature, which directly leads to the defects of LC devices. This paper makes use of the developed homemade temperature control device to realize the construction of high temperature to low temperature environment, using precision LCR meter (Agilent E4980A) and self-built optical path, combined with LC cell capacitance model and dual-cell model, the dynamic response properties of LC materials with temperature change law was explored. The results show that the decay time τd of the LC with positive dielectric anisotropy increases from 12.04 ms to 159.7 ms, and the rotational viscosity coefficient γ1 increases exponentially from 12.04 mPa·s to 1582.45 mPa·s. While τd of the LC with negative dielectric anisotropy increases from 13.10 ms to 408.1 ms, γ1 also increases exponentially from 162.73 mPa·s to 7903.69 mPa·s. The conclusions presented in this paper provide some guidance for the improvement of low temperature properties of LC.