Effect of salt on the phase diagrams of two binary lyotropic liquid crystalline solutions

The effect of adding salts NH₄OH and CsOH to aqueous solutions of NH₄PFO and CsPFO, respectively, was studied for concentrations in the range 0 to 2 wt%. In both systems, the isotropic to nematic and nematic to lamellar phase transition temperatures were elevated. There was an insignificant effect on the width of the nematic range in the NH₄PFO system, while the nematic phase was widened by as much as 3°C in the case of CsPFO. High-resolution X-ray scattering measurements were performed to determine the micellar size and its dependence on temperature for 52 wt % NH₄PFO solution in water.