COEXISTENCE CURVE OF A 3-COMPONENT MICROEMULSION BY A GRADIENT-METHOD

We describe a new gradient technique to determine the coexistence curve of partially miscible liquid mixtures. The method allows this determination to be done using a single sample and gives the proper slice (temperature-order parameter) of the coexistence surface, in contrast to the conventional methods. We employed this technique to determine the coexistence curve of a ternary microemulsion, consisting of water, benzene, and benzyldimethyl-n-hexadecyl ammonium chloride (BHDC), in a narrow temperature range close to the critical point. The value of the exponent beta describing the coexistence curve was found to be 0.34 +/- 0.08.