Phase Field Theory of Heterogeneous Crystal Nucleation

TL;DR

This paper develops a phase field model to study heterogeneous crystal nucleation, analyzing boundary conditions and critical nuclei properties, revealing classical and non-classical wetting behaviors as functions of undercooling.

Contribution

It introduces a phase field approach to model heterogeneous nucleation and explores how boundary conditions influence nucleation behavior and contact angles.

Findings

Critical nuclei properties depend on boundary conditions.

Contact angle varies with undercooling, showing classical and non-classical regimes.

Complete wetting occurs at a critical undercooling.

Abstract

A phase eld approach is developed to model wetting and heterogeneous crystal nucleation of an undercooled pure liquid in contact with a sharp wall. We discuss various choices for the boundary condition at the wall and determine the properties of critical nuclei, including their free energy of formation and the contact angle as a function of undercooling. We nd for particular choices of boundary conditions, we may realize either an analog of the classical spherical cap model or decidedly non-classical behavior, where the contact angle decreases from its value taken at the melting point towards complete wetting at a critical undercooling.