Polymer-dispersed liquid crystals with low volume shrinkage and high peel strength based on epoxy-thiol systems

Polymer-dispersed liquid crystals (PDLCs) with low volume shrinkage and high peel strength were prepared through an epoxy-thiol click reaction catalyzed by the photogenerated base catalyst. The epoxy-thiol reaction was initiated by UV light irradiation, effectively circumventing the environmental sensitivities typically associated with conventional thermally-catalyzed polymerization processes. A systematic study was conducted to examine the impact of polymer concentration, curing temperature, polymerization light intensity and the structure of epoxy on PDLC performance. The results showed that adding a rigid epoxy structure can significantly improve the peel strength, broaden the viewing angle, and smaller the volume shrinkage. Moreover, the incorporation of 25 wt% 2,2-Bis(4-glycidyloxy-phenyl)propane into the PDLC formulation yielded PDLC with an exceptional peel strength of 50.60 N/m, volume shrinkage of 5.06%, and an expansive viewing angle having transmittance above 80% from 0° to 60°, making them highly suitable for flexible PDLC applications.