A dynamical theory of homogeneous nucleation for colloids and macromolecules

TL;DR

This paper develops a dynamical theory for homogeneous nucleation in colloids and macromolecules using fluctuating hydrodynamics, revealing new insights into the nucleation pathways and cluster characteristics.

Contribution

It introduces a nontrivial metric-based gradient descent approach to determine the most likely nucleation path, extending equilibrium free energy methods.

Findings

Most likely nucleation paths can be derived from gradient descent in density space.

Smallest clusters are long wavelength, small amplitude perturbations.

The theory aligns with and extends heuristic free energy approaches.

Abstract

Homogeneous nucleation is formulated within the context of fluctuating hydrodynamics. It is shown that for a colloidal or macromolecular system in the strong damping limit the most likely path for nucleation can be determined by gradient descent in density space governed by a nontrivial metric fixed by the dynamics. The theory provides a justification and extension of more heuristic equilibrium approaches based solely on the free energy. It is illustrated by application to liquid-vapor nucleation where it is shown that, in contrast to most free energy-based studies, the smallest clusters correspond to long wavelength, small amplitude perturbations.