On the derivation of Young's equation for sessile drops: nonequilibrium effects due to evaporation.
Sessile liquid drops have a higher vapor pressure than planar liquid surfaces, as quantified by Kelvin's equation. In classical derivations of Young's equation, this fact is often not taken into account. For an open system, a sessile liquid drop is never in thermodynamic equilibrium and will eventually evaporate. Practically, for macroscopic drops the time of evaporation is so long that nonequilibrium effects are negligible. For microscopic drops evaporation cannot be neglected. When a liquid is confined to a closed system, real equilibrium can be established. Experiments on the evaporation of water drops confirm the calculations.
Butt
Hans-Jürgen
HJ
Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany. butt@mpip-mainz.mpg.de
Golovko
Dmytro S
DS
Bonaccurso
Elmar
E