The H-2-phase of the lyotropic liquid crystal sodium 3,4,5-tris(omega-acryloyloxyundecyloxy)benzoate

The phase behaviour of the lyotropic liquid crystal sodium 3,4,5-tris (omeg a-acryloyloxyundecyloxy)benzoate was investigated by small angle X-ray scat tering. The water content of the lyotropic liquid crystal phase was varied between 8 and 20 wt % and the investigations were performed in a temperatur e range up to 70 degrees C. A reversed hexagonal structure (H-2-phase) as w ell as the isotropic phase were observed. The lattice constant of the H-2-p hase was found to be independent of the water content. An extremely small d ependence on temperature could be found. Based on the shape of the molecule s and the observed structural properties, a model for the arrangement of th e molecules within the H-2-phase is given. The transition temperature from the H-2-phase to the isotropic phase decreases significantly from 60 degree s C for the sample with 8 wt % water content to 30 degrees C for the sample with 20 wt % water content.