ELASTIC MODEL FOR TWISTED NEMATIC TEXTURES IN OOBA LAYERS

An elastic model for the twisted nematic texture observed in nematic c ells containing octyloxybenzoic acid is proposed. According to the mod el the twisted textures are due to the presence of cybotactic groups w hich are responsible for the chirality of the liquid crystal. We show that by assuming for the density of cybotactic groups a critical tempe rature behaviour close to a special temperature, the experimental data can be well interpreted by our mechanical model.