Selective nucleation in porous media

TL;DR

This paper investigates how pore size influences nucleation rates in porous media, revealing a preferred pore size that aligns with the bulk critical nucleus size, offering a way to control nucleation locations.

Contribution

It demonstrates that the optimal pore size for nucleation correlates with the bulk critical nucleus size within Ising lattice gas models, providing a new approach to direct nucleation.

Findings

Optimal pore size matches bulk critical nucleus size

Nucleation rate peaks at specific pore sizes

Provides a method to control nucleation locations

Abstract

Geometrical arguments suggest that pore-mediated nucleation happens in general in a two-step fashion, the first step being nucleation within the pore, the second being nucleation from the filled pore into solution [Page & Sear, Phys. Rev. Lett. 97, 65701 (2006)]. The free energy barriers controlling the two steps of this process show opposite dependencies on pore size, implying that for given thermodynamic conditions there exists a pore size for which nucleation happens fastest. Here we show, within the two- and three-dimensional Ising lattice gas, that this preferred pore size tracks the size of the bulk critical nucleus, up to a numerical prefactor. This observation suggests a simple prescription for directing nucleation to certain locations within heterogeneous porous media.