8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

P6.16Fri 911:10-14:00Phase diagram studies in two surfactant systems ofTriton X-100 employing electrical conductivitymeasurements and optical birefringence observationsParviz Hossein Khani 1 and Mohamad Mehdi Talebi 21 Department of Physic, Faculty of Basic Sciences, I. H. U Tehran-IRAN2 Department of Physic, Faculty of Basic Sciences, Islamic Azad University, North Tehranbranch, Tehran-IRANThe electrical conductivity values in liquid condence media are sensitive to phase changes. Thisproperty has been exploited to study the phase diagrams of two microemulsion systems on thebasis of triton X-100 surfactant as following: (i)Triton X-100/Cyclohexane/Water (ii)(Triton X-100+Butanol)(1:1 by weight)/ Cyclohexane/Water The changes in optical characteristics throughcrossed polaroids were pointed in both systems. The experimental (electrical and optical) studiesperformed by increasing water concentration in mother solutions. The mother solutions were TritonX-100/Cyclohexane or (Triton X-100+Butanol) (1:1 by weight)/ Cyclohexane with differentcyclohexane concentrations. For both the systems, optical characteristics changes were observedthrough crossed Polaroids whenever a phase transformation is occurred. The points correspondingto onset of phase transitions were demarcated on corresponding phase diagrams. The connectionof such points in each phase leads to delineation and mapping of phase diagram. The comparativestudies of the two phase diagrams emphasis the role of butanol addition in the system. Theexistence of butanol as a co-surfactant in (1:1) by weight ratio with respect to surfactant tends to:(i)The disappearance of viscous lyotropic liquid crystalline phases. (ii)The development of softreverse micelle system. (iii)The reduction of normal micelle phase. The normal micelle interfacecould not absorb such excess of butanol. This weight ratio of cosurfactant to surfactant (1:1) is notsuitable for constracting large area normal micelle phase.16