Light scattering from acrylate-based polymer dispersed liquid crystals: theoretical considerations and experimental examples

A light scattering (LS) study made using acrylate-based polymer dispersed l iquid crystals (PDLCs) is presented. The polarized component I,, is measure d for blends of a polyacrylate and the liquid crystal (LC) E7 at several co mpositions. Only the off-state configuration of the droplets with no extern al fields is considered here. These composites consist commonly of micron-s ized nematic LC droplets dispersed in a solid polymer matrix. Theoretical e xpressions for the scattered intensities in the case of isotropic and aniso tropic spherical droplets are given both in the Rayleigh-Gans approximation (RCA) and in the anomalous diffraction approximation (ADA). Series of VV a nd VH components of the scattering intensities are calculated using the mod els of Meeten, Stein and coworkers. The model calculations are compared wit h the light scattering data. This comparison enables us to extract informat ion on the size and the shape of droplets assuming that the size distributi on is uniform and that the scattering is due to single droplets, neglecting inter-particle correlation and multiple scattering effects. This paper dem onstrates that the LS technique is a useful tool for studying the morpholog y of PDLC samples and estimating the average size of nematic droplets.