Excess solubilization of lindane in bicontinuous microemulsions.

We examine the solubilization of a lipophilic molecule (lindane) in the nonionic system water-oil-CiEj, particularly in the microemulsion domain. Solubilization of lindane in this ternary system induces a variation of the HLB temperature and of the efficiency of the surfactant. The temperature of hydrophilic-lipophilic balance (HLB), or better, the temperature of zero spontaneous curvature T of the film, increases or decreases depending on the relative penetration power of oil and solute (lindane) in the amphiphilic film. We observe an excess solubility of lindane in the microemulsion regime, compared to bulk oil at the same temperature. This allows direct determination of the lindane excess adsorbed in the interfacial film referring to a temperature of the zero average curvature. No area per molecule variation associated to lindane penetration could be detected. [ABSTRACT FROM AUTHOR]