Effect of oligomeric surface modifying agent on electro-optical properties of polymer dispersed liquid crystal

In order to lower the driving voltage of polymer dispersed liquid crystal (PDLC), an oligomeric surface modifying agent (SMA) which is a fluoroalkyl terminated polyurethane (PU) oligomer has been synthesized and added to polyurethane acrylate (PUA) resin. With the addition of SMA, contact angle of the resin surface with an LC drop increased and domain size decreased significantly due to the enrichment of SMA molecules at the surfaces. Operating voltage decreased up to 5 phr SMA and increased beyond this content. Regarding the effect of SMA molecular weight, lower molecular weight drove the shutter at lower operating voltage, indicative of more enrichment of the SMA molecules at the surfaces.