Preparation of polymer‐stabilized cholesteric liquid crystal films capable of broadband reflection using a three‐layer system of self‐diffusion

Abstract

Through a simple and effective method for preparing broadband reflective liquid crystal films, the advantages of the three‐layer system are expanded based on the two‐layer system. The cholesteric liquid crystals form a prepolymerized layer after semi‐curing. In the design of the top prepolymerization layer, there is less content of the chiral compound R5011, which results in the formation of cholesteric liquid crystal molecules with a larger pitch. Mainly by controlling the content of polymerizable monomers and UV‐absorbing dyes in cholesteric liquid crystals (CLCs), a polymer network with density gradient distribution suitable for substance diffusion is formed, and the oleophobic substrate on one side of the low‐density polymer network is more likely to be peeled off. In the design of the lowest prepolymerization layer, the content of R5011 is higher, which results in the formation of cholesteric liquid crystals with a larger pitch. One side substrate of two cholesteric liquid crystal cassettes is peeled off and merged into a new liquid crystal cassette whose left and right sides are stacked with septum pads (20 μm), and the nematic liquid crystals are poured into the middle layer to form a three‐layer integrated film. The polymer network of the polymer‐stabilized cholesteric liquid crystals (PSCLCs) itself in the bilayer was used as a diffusion channel. Chiral compounds and UV‐absorbing dyes were diffused from the cholesteric liquid crystal layer to the intermediate nematic liquid crystal layer by diffusion gradient method, resulting in liquid crystal films with arbitrary wavelength bands and ultrawide broadband reflection.

Near-Infrared Reflective Polymer Films Based on UV-327-Doped Zinc Oxide Nanoparticles

“…Cao et al succeeded in preparing polymer-stabilized cholesteric liquid crystal films with broadband reflectivity using a three-layer self-diffusion system, where the polymer network of the bilayer PSCLCs itself was used as a diffusion channel. Chiral compounds and UV-absorbing dyes were diffused from the cholesteric liquid crystal layer to the nematic liquid crystal layer by the diffusion gradient method, controlling the contents of R5011 and UV-327 and adjusting λm and ∆λ to obtain liquid crystal films capable of broadband reflection [27].…”