Dynamics of the “Sponge” (L₃) Phase

Abstract

The dynamics of the sponge structure of the L3-phase in the ternary H2O−C10E4−n-decanol (C10E0) system has been examined. Temperature jump relaxation employing scattered-light detection, pressure jump with conductivity detection, time-resolved electric birefringence, and dynamic light scattering experiments were performed on the same system at varying surfactant volume fraction φ at constant temperature. The observed relaxations were all found to be single exponentials. The time constants τ-1 obtained by these different methods vary over several orders of magnitude. They reveal in part rather strong dependencies on φ obeying effective scaling laws τ-1 ∼ φn, with n = 9 for the temperature and pressure jump relaxation and n = 1 for dynamic light scattering. The time constants from electric birefringence yield n = 3. The origin of the various exponents can theoretically be understood in terms of passage formation, concentration fluctuations, and relaxation of shape anisotropy due to elastic deformation.