The effect of a series of alcohols and ionic surfactants on the cloud point (CP) of nonionic surfactant Dynol-604 has been investigated. The result show that the addition of SDS and CTAB makes the cloud point of Dynol-604 increases greatly and the influence of alcohols on the cloud point of Dynol-604 is complex. When the alcohol is added into the Dynol-604 solution, the system appears double cloud points which are named "upper limit CP" and "lower limit CP" respectively. The phenomenon is discussed using the theory of Cohesion Energy Ratio. The system becomes transparent from turbidity when the temperature is above the upper limit CP. The measurement of the self- diffusion coefficients by the Pulse Field Gradient Spin-Echo Method (PFGSE-NMR) for the upper limit CP solution is carried out and we can conclude that the system is a bicontinuous microemulsion.

Key words: SURFACTANTS, DIFFUSION COEFFICIENTS, DIFFUSION COEFFICIENTS, 1HNMR