Templated droplets and ordered arrays in polymer-dispersed liquid-crystal films

Well-ordered two-dimensional hexagonal arrays of micrometer-sized nematic l iquid-crystal droplets are prepared in polymer films. Droplets of uniform s izes and shapes are formed by "prefabricating" the voids in which the liqui d crystal is to be entrapped. Void preparation involves deposition of polys tyrene microspheres on a substrate to form a colloidal crystal array. The a rray is coated with water-soluble polymer and dried. The microspheres were then extracted with organic solvent. The voids are refilled with liquid cry stal by capillary filling. The materials are characterized throughout this process by atomic force and multiphoton-excited fluorescence microscopies. Polarization-dependent fluorescence images show well-ordered nematic config urations within each droplet. Surprisingly, the nematic alignment in neighb oring droplets is often found to be correlated over large domains spanning several droplets. The origins of these organizational correlations are expl ored.