PHASE-DIAGRAMS AND INTERFACIAL-TENSIONS OF MIXED-AQUEOUS AND NONAQUEOUS MICROEMULSIONS IN MULTICOMPONENT SYSTEMS

The phase diagrams of quaternary systems water + ethylene glycol/n-und ecane/alkylpolyglycol ether were established. In our studies commercia l grade alkylpolyglycol ether mixtures and the hydrocarbon n-undecane were used. The phase diagrams of these systems were determined in depe ndence on the water + ethylene glycol ratio and on the ethoxylation nu mber j of the alkylpolyglycol ether CiEj. In the pseudo-binary concent ration/temperature diagrams (ratio of water (c(w)) to oil (c(o)):c(w)/ c(o)=1) we have Sound 1-, 2-, and S-phase regions. The positions of th e 3-phase regions in these phase diagrams are dependend on the ethoxyl ation number j of the alkylpolyglycol ethers and on the water + ethyle ne glycol ratio in the quaternary system. The interfacial tension (y) of the separated two and three phase systems was measured using the sp inning drop method. The outstanding detergency of microemulsions is co nnected with the ultra-low interfacial tension of about y = 10(-3) mN m(-1) especially against the oil phase. Summarizing all of our results we call conclude that in mixed aqueous and non-aqueous ternary and qu aternary systems microemulsions are formed which are similar to those in aqueous systems.