Effect of mercapto-modified mesoporous silica nanospheres on the electro-optical properties of polymer dispersed liquid crystals

Abstract

Polymer dispersed liquid crystal (PDLC) films are a material developed for smart windows that respond to external electrical stimuli and rapidly change light transmission to flexibly alter the visibility and privacy of a space. In this paper, we synthesised mesoporous silica nanospheres with sulphhydryl modification and successfully prepared nano-PDLC composite films using acrylate as matrix. The results reveal that the film maintains a high contrast ratio of 161 and can switch from non-transparent to transparent with a low applied voltage, even doping 7 wt.% nanomaterials. In addition, we investigated the impacts of UV intensity and polymerisation temperature on the properties of films, and our findings revealed that the size of liquid crystal droplets and the distribution of nanomaterials in the matrix had a direct impact on PDLC performance. An appropriate UV intensity and polymerisation temperature can significantly improve the morphology of polymer matrix and the electro-optical performance of PDLC device. The device not only boasts low power consumption and great CR but also can effectively satisfy the switching requirements of smart windows in different states. Our study provides an effective solution to optimise the performance of PDLC, which lays the foundation for its wide application in various optoelectronic applications.