Steric group-based polymer dispersed liquid crystal composite films with high contrast ratio, low driving voltage and small hysteresis

The unique phase-separated microstructure has endowed polymer dispersed liquid crystals (PDLCs) with outstanding electro-optical performances. However, their applications are hampered by the high driving voltage and low contrast ratio. Attempts to optimize the materials have been made in order to reduce the driving voltage without sacrificing the contrast ratio and other features. Herein, acrylate monomers with different steric end groups were introduced to fabricate PDLCs and their effects on the electro-optical properties and microstructure were investigated. Bipolar droplet configuration was observed in all samples implying tangential anchoring conditions. It was found that the steric end group could affect the morphology of polymer matrix and the electro-optical properties. By carefully adjusting the steric group and doping concentration, the contrast ratio could be enhanced and the driving voltage could be reduced. Besides, hysteresis could also be decreased. The research offers more choices for the construction of PDLCs from material perspective, promoting their potential applications.