Spreading of a droplet on a solid in the partial wetting and non wetting regime by Monte-Carlo simulation

Abstract

The spreading of a spherical droplet, put in contact with a flat solid surface, is simulated using Monte-Carlo algorithm. Two wetting regimes are investigated by changing the energy E ls between atom of droplet (1) and atom of solid (s) and the energy E ll between two droplet atoms: the partial wetting regime and the non-wetting regime. When dealing with the partial wetting regime, a droplet with liquid cap and layered foot is obtained. After the collapse of the liquid cap, a layered droplet with terraces appears at low temperature. At higher temperature, the layers vanish and the liquid cap appears again. When dealing with the non-wetting regime, the droplet ∣ solid interface is reduced to a minimum, as if the droplet was expelled from the solid surface. Whereas molecular dynamics can only handle atomic time scales in the range (ca. 10 −12 to 10 −7 s), it is proved here that the Monte-Carlo algorithm can probe macroscopic time scales (ca. 10 −3 s), whose results are reported here, for the first time, to our knowledge.