Morphological and electro-optical properties of polymer dispersed liquid crystals cured by high intensity laser radiation

We have studied the morphology and the electrooptical properties of Polymer Dispersed Liquid Crystals prepared by the Polymer Induced Phase Separation technique under high-intensity UV laser curing. Photoinduced thermal convective motions have been observed in the directly illuminated area, which originates unusual morphological patterns consisting of ordered and/or disordered structures, depending on the curing intensity. We show that transition between ordered (columnar) and disordered (turbulent) motion is possible by increasing the laser beam intensity and the flow patterns associated to both these regimes can be frozen in by the photo-polymerization process. We show also that localized high-intensity curing generates a gradient of the droplet-size distribution outside the directly irradiated area essentially due to the non-uniform spatial-distribution of scattered intensity. This complex morphology reflects into a peculiar electrooptical behavior that could find potential application in new optical devices.