Effects of Pore Walls and Randomness on Phase Transitions in Porous Media

TL;DR

This paper investigates how pore walls and randomness influence phase transitions in porous media using mean field spin models, revealing that walls significantly affect phase diagram topology.

Contribution

It demonstrates that pore walls are a crucial factor in determining phase diagram topology, linking porous media behavior to random field and anisotropy spin systems.

Findings

Phase diagrams of porous media are topologically similar to those of random field systems.

Walls influence the nature of phase transitions in porous materials.

Presence of walls alters the phase diagram topology in a predictable way.

Abstract

We study spin models within the mean field approximation to elucidate the topology of the phase diagrams of systems modeling the liquid-vapor transition and the separation of He$^3$--He$^4$ mixtures in periodic porous media. These topologies are found to be identical to those of the corresponding random field and random anisotropy spin systems with a bimodal distribution of the randomness. Our results suggest that the presence of walls (periodic or otherwise) are a key factor determining the nature of the phase diagram in porous media.