The formation of a lyotropic mesophase in aqueous solutions of the sodium salt of cellulose acetate sulfate

Aqueous solutions of the sodium salt of cellulose acetate sulfate are shown to be isotropic at concentrations below 42 wt %, biphasic in the concentration range 42-52 wt % in which the isotropic phase-anisotropic phase transition is partially accomplished, and liquid-crystalline at a concentration of higher 52 wt %. The anisotropic phase is represented by different ordered supramolecular structures, such as individual spherulites, spherulite ribbons, fingerprint structures, and other more complex entities. Rheological curves typical of LC systems were recorded; the corresponding concentration and temperature dependences of shear viscosity also prove the existence of an LC state in aqueous solutions of the cellulose acetate sulfate sodium salt. The critical concentration corresponding to the transition of the sodium salt of cellulose acetate sulfate to the LC state at 293-323K was estimated at 52-52.5 wt %.