Effect of Confinement on Capillary Phase Transition in Granular Aggregates
Using a 3D mean-field lattice-gas model, we analyze the effect of confinement on the nature of capillary phase transition in granular aggregates with varying disorder and their inverse porous structures obtained by interchanging particles and pores. Surprisingly, the confinement effects are found to be much less pronounced in granular aggregates as opposed to porous structures. We show that this discrepancy can be understood in terms of the surface-surface correlation length with a connected path through the fluid domain, suggesting that this length captures the true degree of confinement. We also find that the liquid-gas phase transition in these porous materials is of second order nature near capillary critical temperature, which is shown to represent a true critical temperature, i.e., independent of the degree of disorder and the nature of the solid matrix, discrete or continuous. The critical exponents estimated here from finite-size scaling analysis suggest that this transition belongs to the 3D random field Ising model universality class as hypothesized by F. Brochard and P.G. de Gennes, with the underlying random fields induced by local disorder in fluid-solid interactions.
Additional Information© 2020 American Physical Society. Received 10 August 2020; accepted 16 November 2020; published 15 December 2020. The authors would like to thank Professor Mehran Kardar (Department of Physics at MIT) for reviewing the first draft of this paper and providing very insightful suggestions, including carrying out a finite-size scaling analysis. The authors also thank Professor Emanuela Del Gado (Department of Physics at Georgetown University) for reviewing the last draft of this paper before its final version and providing critical feedback incorporated into this final version. S. M. and T. Z. also thank Professor Enrico Masoero (School of Engineering at Newcastle University) for fruitful discussions. T. Z. thanks the Drinkward Fellowship at Caltech's Mechanical and Civil Engineering Department.
Published - PhysRevLett.125.255501.pdf
Submitted - 2008.04201.pdf
Supplemental Material - capillary_criticality_SI_FINAL_11162020.pdf