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Wetting of Methanol on the n-Alkanes: Observation of Short-Range Critical Wetting



David J. Ross, D Bonn, J Meunier


We present results of the wetting properties of methanol at the liquid-vapor interface of different n-alkanes ranging from hexane to undecane. Measurement of the contact angle shows that, as the bulk critical point is approached, wetting transitions occur for long alkanes, whereas drying is found for short alkanes. Measurement of the wetting layer thickness, as well as precise contact angle measurements close to the wetting temperature Tw, reveal a change in the order of the transition. First order (discontinuous) wetting occurs for Tw far from the bulk critical point Tc. Critical (continuous) wetting is observed for Tw close to Tc. The observed critical wetting transition has all the features of the long-sought short-range critical wetting transition. We argue that it is possible to observe short-range critical wetting in this system, because the long-range van der Waals interactions are negligible for wetting transitions close to the bulk critical point.
Journal of Chemical Physics
No. 6


contact angle, critical wetting, methanol, n-alkanes


Ross, D. , Bonn, D. and Meunier, J. (2001), Wetting of Methanol on the n-Alkanes: Observation of Short-Range Critical Wetting, Journal of Chemical Physics (Accessed April 19, 2024)
Created February 8, 2001, Updated February 17, 2017