Bilayer Cholesteric Liquid Crystal Film With Broadband High‐Reflectivity via a Poly(Vinyl Alcohol) Barrier Layer for Infrared Shielding and Anti‐Counterfeiting

ABSTRACT This study prepares a bilayer broadband high‐reflectivity polymer‐stabilized cholesteric liquid crystal (PSCLC) film based on a PSCLC‐PVA‐PSCLC structure. The poly(vinyl alcohol) (PVA) interlayer effectively blocks the diffusion of chiral molecules between the upper and lower films, thereby preventing the racemization induced by interaction between chiral compounds of opposite handedness in conventional multilayer systems; meanwhile, the PVA layer addresses the severe light scattering and loss defects resulting from insufficient interfacial adhesion. On this basis, gradient pitch distributions are constructed in the upper and lower layers, respectively. Through systematic optimization of the liquid crystal composition and UV polymerization conditions, broadband overlap of the bilayer reflection spectra is achieved, significantly expanding the high‐reflectivity bandwidth. Polarized optical microscopy characterization confirms that the structure maintains a well‐aligned planar texture. This study further explores the application potential of the bilayer high‐reflectivity film in infrared shielding and patterned anti‐counterfeiting. The work not only provides new insights for solving the problems of racemization and interfacial loss in high‐reflectivity films but also offers a feasible technical pathway for the development of infrared shielding materials and optical anti‐counterfeiting devices.