Small liquid crystal droplet formation of polymer-dispersed liquid crystal under ultraviolet light irradiation without short wavelength component

The light scattering properties and polymer morphology of polymer-dispersed liquid crystal films were investigated while adjusting the spectrum of ultraviolet light irradiation with several optical filters in their formation process of photopolymerization-induced phase separation. It is found that the short wavelength light component of less than 355 nm, which is contained in ultraviolet light to be irradiated, slows the phase separation process and results in the formation of large liquid crystal droplets. The morphological changes in the polymer may be due to undesirable decomposition products created in the nematic liquid crystal under the short wavelength ultraviolet irradiation. A spectral arrangement using an optical filter to eliminate the short wavelength light is useful in obtaining small liquid crystal droplets with a strong light-scattering effect, which increases the extinction ratio of polymer-dispersed liquid crystal films. This formation technique will also improve photochemical damage in the phase separation process.