Temperature dependence of dynamic response of liquid crystal materials

Abstract

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 τ_d 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 τ_d 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.

Keywords:

• dynamic response
• rotational viscosity coefficient
• temperature dependence
• thermoelectric refrigeration

Additional information

Funding

This research is supported by the Natural Science Foundation of Hebei Province of China [A2019202235]; the Research and practice project of Hebei Province higher education and teaching reform [2017GJJG018]; Research Projects of Undergraduate Education and Teaching Reform in Hebei University of Technology [201802003]; the Special Project of China Association of Higher Education [21LKYB05]; Science and Technology Project of Guannan County [GN202101]; Project of College Students Innovation and Entrepreneurship Training Program [202210080015].