Morphological control and switchable photoluminescence responses of silica nanoparticles-modified polymer-dispersed liquid crystal composite films

Abstract

AbstractAn electro-optic tunable device is fabricated by the incorporation of silica nanoparticles as a dopant into polymer-dispersed liquid crystal composite film followed by UV curing through polymerisation-induced phase separation process. These silica-modified fibrous aggregates of polydimethylsiloxane provide stability to the nematic liquid crystal molecules. The interaction between dispersed silica nanoparticles and modified polymer network improves the polymer/liquid crystal interface, which was successfully analysed through scanning electron microscopy. It also controlled the birefringence in nematic liquid crystal droplets and provided optical stability to the off-state (opaque) scattering of an electro-optic device. The electrical tuning of photoluminescence intensity during the stage triggering from 'Switch OFF state' to 'Switch ON state' shows dependence on the morphology of composite films. It can find out potential applications in electrically switchable shutters in display market.Keywords: liquid crystal shutter devicepolymer-dispersed liquid crystal compositesinterfacephotoluminescenceelectro-optic switching AcknowledgementsThe author would like to thank M/s Norland, NJ, for providing the polymer and E. Merck, UK, for providing liquid crystal materials, and financial support from University Grant Commission (UGC) is gratefully acknowledged.