Electrothermal Switching Characteristics from a Hydrogen-Bonded Polymer Network Structure in Cholesteric Liquid Crystals with a Double-Handed Circularly Polarized Light Reflection Band

Abstract

In this study, cholesteric liquid crystal (Ch-LCs) composite with a double-handed circularly polarized light reflection band that contains hydrogen-bonded (H-bonded) polymer network was fabricated by a polymer template method, in which the environmental sensitivity and reversibility of hydrogen bond and memory effect of the polymer template were incorporated into the polymer stabilized cholesteric liquid crystal (PSCLCs) film. The thermal and electrical tunability of the Ch-LCs composite before and after irradiation were investigated. It has been demonstrated that reflection characteristics of the Ch-LCs composite derived from H-bonded chiral monomer (HBCM) after irradiation exhibited strong temperature sensitivity with temperature change, which we believe is due to that helical twisting power value of both HBCM and cholesteryl additives increased with an increasing temperature. Additionally, the reflective wavelength of the Ch-LCs composite before and after irradiation can be electrically switched to reflect green from the initial state reflecting a red color. The modulating mechanism is due to Helfrich deformation in which the tilt of helices axis in the Ch-LCs composite was induced when a voltage was applied. The technique developed in this study has great applications such as tunable lasers, optical sensors and LCs displays.