Epitaxy in simple classical fluids in micropores and near-solid surfaces

Abstract

The behaviour of fluids near solid-fluid interfaces is important in a number of fields^1–4 and is receiving renewed attention⁵. Previous computational studies^6–11 of the prototype split-pore—an atomic fluid contained between two infinite, plane-parallel solid surfaces (walls)—demonstrate that the fluid piles up in layers parallel to the walls. Yet none of these investigations finds long-range order within the fluid layers in directions parallel to the walls. In contrast, our Monte Carlo study of the prototype with structured walls reveals that at critical inter-wall separations the fluid layers take on solid-like order, that is, the fluid 'freezes' to a solid reflecting the structure of the wall. This epitaxy decreases with increasing inter-wall separation, but persists indefinitely in the contact layer. Such epitaxy may occur at aqueous-solid interfaces in geological^1,2,4 and biological^2,3 systems.