The theory of droplet diffusiophoresis for concentrated solutions

The theoretical diffusiophoresis velocity is obtained for a droplet of a co ncentrated solution suspended in a binary gaseous mixture. The droplet is c haracterized by a high thermal conductivity. The droplet radius is assumed to be much greater than the mean free path for gaseous-mixture molecules. O ne of the gaseous-mixture molecular components is the vapor of the droplet solvent. According to the formula obtained in this study, the droplet is dr iven toward lower concentration of the volatile gaseous-mixture component b y diffusive slip and in the opposite direction by phase transition. An incr ease in the relative mass concentration of the volatile solvent in the drop let enhances effects associated with the dependence of surface tension on t he volatile-component concentration and the reactive transport due to the s urface nonuniformity of phase transition. As the relative mass concentratio n of the volatile solvent in the droplet approaches unity, the effect of di ffusive slip tends to vanish. (C) 2000 MAIK "Nauka/Interperiodica".