The light scattering and electro-optic response of new material with display potential are investigated. The materials consist of microdroplets of nematic liquid crystals which are spontaneously formed in a solid polymer at the time of its polymerization. Droplet size, spacing, and distribution are readily controlled in these materials to allow optimization of displays based upon electrically controlled light scattering from the liquid crystal droplets. Preliminary experimental and theoretical studies of the light scattering properties show these materials to offer new features suitable for many display applications.

The ability to generate regular spatial arrangements of particles is an important technological and fundamental aspect of colloidal science. We showed that colloidal particles confined to a few-micrometer-thick layer of a nematic liquid crystal form two-dimensional crystal structures that are bound by topological defects. Two basic crystalline structures were observed, depending on the ordering of the liquid crystal around the particle. Colloids inducing quadrupolar order crystallize into weakly bound two-dimensional ordered structure, where the particle interaction is mediated by the sharing of localized topological defects. Colloids inducing dipolar order are strongly bound into antiferroelectric-like two-dimensional crystallites of dipolar colloidal chains. Self-assembly by topological defects could be applied to other systems with similar symmetry.

Colloidal particles inside a liquid crystalline solvent can be manipulated to create knots of arbitrary shape and complexity.

Phenomenological Landau-de Gennesmodelling based on the free energy of nematic liquid crystal colloids is reviewed. Nematic phase, gradient of order, and surface anchoring contributions to the total free energy are used. The numerical finite difference relaxation technique is explained as an efficient tool for the minimisation of the free energy. Effects of the mesh and mesh allocation are discussed. Various conceptually different colloidal structures are calculated to show the universality of themodel. Single particles, dipolar-quadrupolar dimers, entangled dimers, dimers bound by escaped hyperbolic rings, and hierarchically patterned Saturn-ring colloidal superstructures are presented. © 2009 Taylor and Francis

Computer simulations are made of polarizing microscope textures of supramicron-sized nematic droplets with director configurations which commonly occur in polymer and other dispersions. The simulations are computed from polarization rotations and phase shifts caused by nonuniform optical anisotropies of the nematic structure in liquid crystal droplets. The treatment is limited to the case of spherical droplets which are optically soft so that reflection and refraction at the droplet surface, as well as refraction on any internal structure, can be neglected. Simulated polarizing microscope textures of four different director configurations at different orientations are presented graphically. The simulated pictures are shown to compare well with observations of actual nematic droplets viewed under crossed polars.