Condensation and Evaporation Transitions in Deep Capillary Grooves

0435405 - ÚCHP 2015 RIV GB eng J - Journal Article
Malijevský, Alexandr - Parry, A.O.
Condensation and Evaporation Transitions in Deep Capillary Grooves.
Journal of Physics-Condensed Matter. Roč. 26, č. 35 (2014), s. 355003. ISSN 0953-8984. E-ISSN 1361-648X
R&D Projects: GA ČR GA13-09914S
Grant - others:EPSRC UK(GB) EP/J009636/1
Institutional support: RVO:67985858
Keywords : phase equilibria * narrow pores * fluids
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 2.346, year: 2014

We study the order of capillary condensation and evaporation transitions of a simple fluid adsorbed in a deep capillary groove using a fundamental measure density functional theory (DFT). The walls of the capillary interact with the fluid particles via long-ranged, dispersion, forces while the fluid-fluid interaction is modelled as a truncated Lennard-Jones-like potential. We find that below the wetting temperature T-w condensation is first-order and evaporation is continuous with the metastability of the condensation being well described by the complementary Kelvin equation. In contrast above T-w both phase transitions are continuous and their critical singularities are determined. In addition we show that for the evaporation transition above T-w there is an elegant mapping, or covariance, with the complete wetting transition occurring at a planar wall. Our numerical DFT studies are complemented by analytical slab model calculations which explain how the asymmetry between condensation and evaporation arises out of the combination of long-ranged forces and substrate geometry.
Permanent Link: http://hdl.handle.net/11104/0239296