Fine adjustment of conductivity in polymer-dispersed liquid crystals

The electrical properties of polymer-dispersed liquid crystals (PDLCs) are an important characteristic in their electro-optical performance. Conductivity effects can set up depolarization fields in the films reducing the effective field across the liquid crystal droplets. Both theoretical and experimental investigations have confirmed that the electric field across nematic droplets depends on the liquid crystal and polymer conductivities. In this letter, we have found that the doping of a PDLC with low percentages of a conductive polymer allows a fine adjustment of polymer matrix conductivity. In addition, we have found a large reduction in the re-orientation fields and relaxation times as a function of conductive polymer loading. Results are in rather good agreement with a simple phenomenological model. (C) 2004 American Institute of Physics.