Journal of Chemical Physics, Vol.115, No.18, 8575-8582, 2001
Wetting transitions at the air-liquid interface of water plus tetradecane+C6E2 mixtures
In this study, the interfacial phenomena and the wetting behaviors of the ternary system water+tetradecane+diethylene glycol monohexyl ether (C6E2) were carefully examined at 20 degreesC. There is one three-liquid-phase-coexisting tie triangle and three two-liquid-phase-coexisting envelopes in the triangle phase diagram of the system water+tetradecane+C6E2 at 20 degreesC. In the two-liquid-phase-coexisting region on the water/C6E2 side, the upper C6E2-rich liquid phase exhibits a sequence of transition: nonwetting --> partial wetting --> complete wetting at the lower aqueous phase/air interface by simply varying the system composition. Similarly, in another two-liquid-phase-coexisting region on the tetradecane/C6E2 side, the upper tetradecane-rich liquid phase also demonstrates a sequence of transition at the lower C6E2-rich phase/air interface. Some of these wetting transitions can be deduced by the critical wetting theory of Cahn, while the other transitions seem to have no obvious relevance to a critical end point.