Low‐Temperature Properties of Polymer‐Stabilised Liquid‐Crystal Blue Phases

Abstract

The temperature dependences of the Kerr coefficient and the response time in the electrooptical effect of polymer-stabilised blue phases (PSBPs) of liquid crystals (LCs) with various polymer concentrations are investigated in a wide temperature range including temperatures lower than room temperature. The Kerr coefficients are found to abruptly decrease at low temperature, and the response time-temperature relation obeys the Arrhenius equation. For comparison of the Kerr effect and molecular rotation at low temperature, various physical properties such as permittivity, rotational relaxation time and dielectric relaxation strength of the PSBPs are investigated. The electrooptical response times and the dielectric relaxation times show different temperature dependences, and rotation of LC molecules in PSBPs was sufficiently active at low temperature and not strongly affected by the polymer.

Enhanced Low-temperature Electro-optical Kerr Effect of Stable Cubic Soft Superstructure Enabled by Fluorinated Polymer Stabilization

“…Herein, we report an efficient strategy to enhance Kerr effect of PSBPLC at the low temperature enabled by a judiciously designed fluorination of polymer network. The optimized material exhibited a conspicuous electric-field induced Kerr effect at −50 °C, achieving a remarkable enlarged Kerr constant which was approximately two orders of magnitude larger with respect to the aforementioned prior result 32 . Although the polymer fluorination was previously employed in polymer-LC material system to promote the room-temperature performances of relevant devices 33 , low-temperature-applicable PSBPLC with desirable EO Kerr performance was still a challenging issue.…”

Phase Transition and Electro‐Optic Studies in Polymer Stabilized Blue Phase Liquid Crystal

“…Blue phases (BPs) in liquid crystals generated enormous interest among researchers due to its distinguished optical properties and technological applications. BPs are thermodynamically stable existing between cholesteric and isotropic phases in a narrow temperature range of 1°C . Three types of blue phases BP‐I, BP‐II and BP‐III are known to exist .…”