Line-tension effects on heterogeneous nucleation on a spherical substrate and in a spherical cavity

摘要

The line-tension effects on heterogeneous nucleation are considered when aspherical lens-shaped nucleus is nucleated on top of a spherical substrate andon the bottom of the wall of a spherical cavity. The effect of line tension onthe nucleation barrier can be separated from the usual volume term. As theradius of the substrate increases, the nucleation barrier decreases andapproaches that of a flat substrate. However, as the radius of the cavityincreases, the nucleation barrier increases and approaches that of a flatsubstrate. A small spherical substrate is a less active nucleation site than aflat substrate, and a small spherical cavity is a more active nucleation sitethan a flat substrate. In contrast, the line-tension effect on the nucleationbarrier is maximum when the radii of the nucleus and the substrate or cavitybecome comparable. Therefore, by tuning the size of the spherical substrate orspherical cavity, the effect of the line tension can be optimized. Theseresults will be useful in broad range of applications from material processingto understanding of global climate, where the heterogeneous nucleation plays avital role.