The nematic-isotropic and the nematic-to-lamellar phase changes in the lyotropic liquid crystal formed by decylammonium chloride micelles in a water-ammonium chloride solution have been studied by light scattering. The former transition shows behavior identical to that observed in thermotropic liquid crystals. The nematic-lamellar transition appears closely similar to a thermotropic nematic-smectic-A change and the elastic constants diverge according to the analogy to superfluid helium and the three-dimensional xy model.
