title: Motion of a drop on a solid surface due to a wettability gradient.
abstract: The hydrodynamic force experienced by a spherical-cap drop moving on a solid surface is obtained from two approximate analytical solutions and used to predict the quasi-steady speed of the drop in a wettability gradient. One solution is based on approximation of the shape of the drop as a collection of wedges, and the other is based on lubrication theory. Also, asymptotic results from both approximations for small contact angles, as well as an asymptotic result from lubrication theory that is good when the length scale of the drop is large compared with the slip length, are given. The results for the hydrodynamic force also can be used to predict the quasi-steady speed of a drop sliding down an incline.
authors.affiliation: Department of Chemical and Biomolecular Engineering, Clarkson University, Potsdam, New York 13699, USA.
authors.forename: R Shankar
authors.initials: RS
authors.lastname: Subramanian
authors.forename: Nadjoua
authors.initials: N
authors.lastname: Moumen
authors.forename: John B
authors.initials: JB
authors.lastname: McLaughlin
mesh_terms: D057446:Hydrodynamics; D008153:Lubrication; D009038:Motion; D012996:Solutions; D013499:Surface Properties; D017155:Wettability
chemical_list: D012996:Solutions