LIGHT-SCATTERING FROM A SURFACTANT SPONGE PHASE - EVIDENCE FOR A HIDDEN SYMMETRY

New light-scattering data from an anomalous isotropic phase in a bilayer forming surfactant system (sponge phase) are analysed using a Landau-Ginzburg theory with two fluctuating order parameters: One the surfactant density, and the other associated with an wideloutsidesymmetry that arises in bilayer containing systems. The scattering shows a clear signature of this additional order parameter. The concentration dependence of the osmotic compressibility provides strong evidence for fluctuation-induced logarithmic corrections to the elasticity andlor area parameters of the bilayer. © 1990 The Japan Society of Applied Physics.