Eur. Phys. J. E (2007) 22: 41-49
https://doi.org/10.1140/epje/e2007-00011-4

Regular Articles

Formation and mobility of droplets on composite layered substrates

¹ Department of Physics, University of California, Berkeley, CA, 94720-7300, USA
² Department of Chemical Engineering and Minerva Center for Nonlinear Physics of Complex Systems, Technion - Israel Institute of Technology, 32000, Haifa, Israel

^* e-mail: yochelis@ucla.edu

Received: 20 August 2006
Published online: 21 February 2007

Abstract

A mesoscale fluid film placed on a solid support may break up and form droplets. In addition, droplets may exhibit spontaneous translation by modifying the wetting properties of the substrate, resulting in asymmetry in the contact angles. We examine mechanisms for droplet formation and motion on uniform and terraced landscapes, i.e., composite substrates. The fluid film stability, droplet formation and velocity are studied theoretically in the isothermal case using a lubrication approach in one spatial dimension. The droplet properties are found to involve contributions from both the terraced layer thickness and molecular interactions via the disjoining potential.