Dielectric behavior of polymer-stabilized-liquid-crystal cells made from hosts with different ultraviolet absorptions

摘要

Small concentrations (<7%) of reactive mesogen were introduced into liquid-crystal materials and filled into standard homogeneous planar-aligned cells, and the physical properties of the resulting polymer-stabilized-liquid-crystal cells were deduced from capacitance measurements. Two nematic liquid-crystal hosts were compared (E7 and ML1001), the former with significant ultraviolet absorption and the latter with negligible absorption. This paper uses capacitance results to find a model, which describes best the cells' dielectric switching properties measured for both liquid-crystal hosts. Several models, considering the polymer network formed is totally rigid, totally elastic, or with mixed properties, are compared. Using a specific fitting routine, the unknown parameters for each model are determined to provide the best agreement between the observed and predicted electro-optic behavior. The quality of the fit is discussed for each model and that based on the well-known continuum energy expression for a simple nematic liquid crystal is found to give the best results. (C) 2004 American Institute of Physics.