Liquid droplet spreading with line tension effect

Abstract

For a macroscopic liquid droplet, we applied the fluid mechanics to predict its dynamicspreading where the energies associated with volume are dominant (e.g. Shikhmurzaev 1997J. Fluid Mech. 334 211). When the droplet size is reduced to the sub-millimetre level, thesurface energy becomes the dominant factor. If the droplet size is further reduced to themicrometre or sub-micrometre level, the line tension should be included in our theoreticalformulation for predicting droplet spreading. In the present paper, we extend thenon-equilibrium thermodynamics (Gao et al 2000 Acta Mater. 48 863–74) to describe themicrometre or nanometre size droplet spreading on a solid substrate with the line tensioneffect. Discussion of the stable and unstable equilibrium states is made based on thethermodynamic force expression.