Molecular Crystals and Liquid Crystals, Vol.552, 111-122, 2012
Polymer Network Morphology and Electro-Optical Properties of Electrothermal Switchable Bistable Polymer-Stabilized Cholesteric Texture Light Shutters with Various Chiral Dopant Concentrations
Electrothermal switchable bistable (ETSB) polymer-stabilized cholesteric (Ch) texture (PSCT) light shutters (ETSB-PSCT) with various chiral dopant concentrations were fabricated and the effects of the chiral dopant concentrations on the morphology of polymer network and electro-optical performances of ETSB-PSCT were studied. As the chiral dopant concentrations increased, higher monomer concentrations were required to maintain the unwound homeotropic texture of the cholesteric liquid crystals for the fabrication of the ETSB-PSCT. Electro-optical measurements indicated that as the chiral dopant concentration increased, the contrast ratio of the scattering and transparent states of the ETSB-PSCT increased. In particular, 12 wt% ETSB-PSCT exhibited optimum electro-optical performance. We also discovered that 3 wt% ETSB-PSCT possessed two stable optical states at zero field, under two different rates of the removal of the voltage. This development has paved the way for the possible fabrication of electro-electro switchable bistable PSCT (EESB-PSCT) light shutters.
Keywords:Bistable light shutter;chiral dopant concentration;monomer concentration;polymer-stabilized cholesteric texture