CRITICAL-BEHAVIOR IN QUATERNARY MICROEMULSION MIXTURES - EXPERIMENTAL-DETERMINATION OF UNIVERSAL SCALING LAWS

We present light scattering, density, and interfacial tension results obtained for a four-component system in two distinct points of a critical line. The system consists of mixtures of water, dodecane, pentanol, sodium dodecyl sulfate. The experiments have been performed at constant temperature in both the one-phase and two-phase regions along different paths. For each critical point investigated, effective critical exponents nu, gamma, beta, and mu were measured. Although their values are smaller than the Ising one, they verify with a reasonably agreement the following theoretical predictions: gamma = 2-nu, mu = 3,88-beta, and mu + nu = gamma + 2-beta. The new results reported in this paper show that the choice of the path followed cannot explain the anomalous behavior observed. In contrast they are consistent with the recent interpretation proposed by Gazeau et al. (Europhys. Lett. 1989, 9, 833) of a crossover between two critical phenomena.