Temperature-independent pitch invariance in cholesteric liquid crystal

Abstract

We report a pitch invariance in cholesteric liquid crystals (CLCs) independent of temperature by mixing two chiral dopants. One dopant tends to shorten the helical pitch of the CLC, but the other makes the pitch longer, with increasing temperatures. From an analysis of temperature dependencies of the pitch for each dopant, we determined the mixing ratio of two chiral dopants for the pitch invariance. Finally, we obtained the pitch-invariant CLCs to temperature and the helical twisting power of the mixed dopant was estimated.

Wavelength-tunable and shape-reconfigurable photonic capsule resonators containing cholesteric liquid crystals

“…To render the CLC temperature-sensitive in the range of 18° to 34°C, we formulate the core solution to have 0.68% (w/w) of R5011 and 19.8% (w/w) of R811. The chiral dopant R5011 is insensitive to a temperature below 50°C, whereas the chiral dopant R811 is highly sensitive in the range of 10° to 40°C ( 33 , 34 ); the mechanism by which the stop band shifts along with temperature is known as the temperature-dependent solubility and twisting power of the dopant ( 35 ). This specific composition of the CLC solution has a central stop band at 669 nm at 18°C, which shifts to 539 nm at 34°C (fig.…”

Easily Processable Temperature-Responsive Infrared-Reflective Polymer Coatings

“…It should be noted that the slight decrease of the helical twisting power of chiral dopant S811 with decreasing temperature will only have a minor contribution to the gradual λ B change. 47,48…”

Temperature‐Responsive Photonic Devices Based on Cholesteric Liquid Crystals

“…Adapted under terms of the CC‐BY license. [ 77 ] Copyright 2014, OSA Publishing. Adapted with permission.…”