Electro-optics and structure of polymer dispersed liquid crystals doped with nanoparticles of inorganic materials

Electro-optic characteristics and structural peculiarities of polymer dispersed liquid crystals (PDLC) doped with small amount (<= 3 vol.%) of inorganic nanoparticles (NP) are considered. These composites were formed by the photoinduced phase separation of the LC-NP-Prepolymer mixtures. It is established that NP do not change essentially PDLC morphology of LC-Polymer samples. In the course of the phase separation, they are mainly involved with polymer, serving as building blocks for the polymer matrix. The large and/or strongly aggregating particles strengthen light scattering in the polymer that may enhance electrooptic contrast. In turn, the small and weekly aggregating particles modify the effective refractive index of the polymer phase without producing any noticeable optical inhomogeneity. The latter is used to tune the refractive index ratio of LC and polymer in order to meet conditions for the substantial reduction of off axis haze in the field-on state. (c) 2006 Elsevier B.V. All rights reserved.