Functionalized polyhedral oligomeric silsesquioxane-based polymer dispersed liquid crystal films with low driving voltage and high contrast ratio

In this study, an effective method was demonstrated to improve the performance of polymer dispersed liquid crystal (PDLC) films by incorporating nano-sized polyhedral oligomeric silsesquioxane (POSS) particles into the polymer matrix. The thiol-functionalized POSS dispersed uniformly in the polymer phase by participating in the crosslinking reaction of epoxy and thiol monomers. Consequently, low driving voltages within the safety range were achieved by introducing POSS in percentage of 6 wt%, due to the combined effects of regulating the polymer morphology and lowering the surface energy. Moreover, the contrast ratio was improved to be higher than 300. Stability and switchability were also verified in on-off cycles, indicating its lifetime of as least 50000 cycles. In addition, the epoxy and thiol material system contributed to the outstanding mechanical strength, which could help maintain the electro-optical properties even in flexible films. This work could provide an effective approach for the optimization of PDLC films and promote their potential applications in fields such as flexible displays and smart windows.