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

Published

February 8, 2001

Author(s)

David J. Ross, D Bonn, J Meunier

Abstract

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 T_w, reveal a change in the order of the transition. First order (discontinuous) wetting occurs for T_w far from the bulk critical point T_c. Critical (continuous) wetting is observed for T_w close to T_c. 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.

Citation

Journal of Chemical Physics

Volume

114

Issue

No. 6

Pub Type

Journals

Keywords

contact angle, critical wetting, methanol, n-alkanes

Citation

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 23, 2024)