Recent Advances in Electro-Optic Response of Polymer-Stabilized Cholesteric Liquid Crystals

Abstract

Cholesteric liquid crystals (CLC) are molecules that can self-assemble into helicoidal superstructures exhibiting circularly polarized reflection. The facile self-assembly and resulting optical properties makes CLCs a promising technology for an array of industrial applications, including reflective displays, tunable mirror-less lasers, optical storage, tunable color filters, and smart windows. The helicoidal structure of CLC can be stabilized via in situ photopolymerization of liquid crystal monomers in a CLC mixture, resulting in polymer-stabilized CLCs (PSCLCs). PSCLCs exhibit a dynamic optical response that can be induced by external stimuli, including electric fields, heat, and light. In this review, we discuss the electro-optic response and potential mechanism of PSCLCs reported over the past decade. Multiple electro-optic responses in PSCLCs with negative or positive dielectric anisotropy have been identified, including bandwidth broadening, red and blue tuning, and switching the reflection notch when an electric field is applied. The reconfigurable optical response of PSCLCs with positive dielectric anisotropy is also discussed. That is, red tuning (or broadening) by applying a DC field and switching by applying an AC field were both observed for the first time in a PSCLC sample. Finally, we discuss the potential mechanism for the dynamic response in PSCLCs.

The association of structural chirality and liquid crystal anchoring in polymer stabilized cholesteric liquid crystals

“…These formulations differ only by the relative initial pitch length ( P o ), which have been shown to respond in a similar manner to their shorter pitch length analogs, with the relative response dependent only on the polymerization conditions. 79,80…”

Smart Switchable Window with Bistability and Tunability of Transmission

“…The scattering based technologies include polymer dispersed liquid crystals (PDLCs), [16][17][18][19][20][21] polymer stabilized liquid crystal (PSLC), [22][23][24][25][26][27][28][29] and polymerstabilized cholesteric textures (PSCTs). [30][31][32][33][34][35][36][37] In one state under a specific voltage condition, the liquid crystal in the window is in an optically uniform state and is transparent. In another state with a different voltage condition, the liquid crystal is in a multidomain state and is scattering.…”

Structural coloured epoxy resin patterns prepared using thermochromic epoxy liquid crystal mixtures

“…14,15 If this polymerization is carried out at the cholesteric phase, a cholesteric LCN (CLCN) is obtained. 16…”

“…14,15 If this polymerization is carried out at the cholesteric phase, a cholesteric LCN (CLCN) is obtained. 16 Polyacrylate CLCN films have been extensively studied since 1980s and 1990s, [17][18][19] and much attention has been paid to functionalities on them. [20][21][22][23][24][25][26][27][28][29] They are potentially applied in decoration, displays, and anti-counterfeiting.…”