Liquid crystal polymer composites with photo- and mechanically tunable optical properties

Subject of study . Elastic polymer composites based on glycerol-plasticized polyvinyl alcohol containing dispersed droplets of photosensitive cholesteric liquid crystals were investigated. Aim of study. The aim was to synthesize new composite materials with photo- and mechanically tunable optical properties and to analyze the effect of ultraviolet (UV) irradiation and mechanical deformation on the selective light reflection (SLR) spectra of the composite films. Method. The composite films were subjected to UV laser irradiation and deformed at a constant stretching rate while their SLR spectra were continuously recorded. The effects of irradiation time and the degree of film deformation on film color were studied, and the mechano-optical behaviors of the films before and after irradiation were compared. Main results. Upon UV irradiation, the SLR spectral peak of the composites shifted to the short-wavelength region of the spectrum by 27 nm. With deformation of both the irradiated and nonirradiated films, up to 100% stretching, their SLR spectral peaks shifted to the short-wavelength region by 60 nm. The process was reversible, and after fixation of the sample, the peak reverted to its original position. Practical significance. The results obtained may serve as a basis for the development of a new generation of multisensory smart materials for information recording and storage, deformation sensors, protective devices with latent images, and other high-tech applications.