Surface anchoring effects on spectral broadening of cholesteric liquid crystal films

Abstract

This paper describes the spectral broadening of cholesteric liquid crystal film prepared from a blend comprising a cross-linkable liquid crystal polymer and a non-cross-linkable low-molecular-weight liquid crystal. The spectral broadening arises from the formation of gradient pitch across the film thickness. It is shown that both phase-separation and in situ swelling during photopolymerization are important mechanisms for the resulting film structure. The surface anchoring is important to achieve high wavelength- and polarization-selective reflectance.

Electrically induced bandwidth broadening in polymer stabilized cholesteric liquid crystals

“…[5][6][7][8][9][10][11] Using differences in monomer reactivity and diffusion properties, polymer stabilized CLCs (PSCLCs) with considerably broadened reflection notches were formed that could be rapidly switched from a broadened state to a transparent state with relatively high applied electrical fields (>10 V/lm). Once formed however, the breadth of the notch could not be changed, only turned on or off.…”

Electrically switchable multi-stable cholesteric liquid crystal based on chiral ionic liquid

“…For ionic impurities of doping, Hu et al [10] used a chiral ionic liquid (CIL)-doped CLC material to obtain a wideband reflected state by forming a pitch gradient. The wide-band reflected state [11][12][13][14] can selectively reflect circularly polarized light covering the whole visible spectrum and has enormous potential for practical applications, such as full-colored display, brightnessenhancement films, and so on. Although the fewer ions that are in a liquid crystal host, the better its electrooptical performance of a device, there is a range to add ionic impurities for wider application that does not have a strict requirement on electro-optical performance, such as response time, threshold voltage, or saturation voltage.…”

Cholesteric Liquid Crystals with a Broad Light Reflection Band

“…In Refs. 165–167, the methodology given in Ref. 163 was reproduced and applied to different CLC blends, which demonstrates the generic nature of the procedure.…”