Density Functional Study of Comlete, First-Order and Critical Wedge Filling Transitions

0425939 - ÚCHP 2014 RIV GB eng J - Journal Article
Malijevský, Alexandr - Parry, A.O.
Density Functional Study of Comlete, First-Order and Critical Wedge Filling Transitions.
Journal of Physics-Condensed Matter. Roč. 25, č. 30 (2013), s. 305005. ISSN 0953-8984. E-ISSN 1361-648X
R&D Projects: GA ČR GA13-09914S
Institutional support: RVO:67985858
Keywords : capillary condensation * narrow pores * covariance
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 2.223, year: 2013

We present numerical studies of complete, first-order and critical wedge filling transitions, at a right angle corner, using a microscopic fundamental measure density functional theory. We consider systems with short-ranged, cut-off Lennard-Jones, fluid-fluid forces and two types of wall-fluid potential: a purely repulsive hard wall and also a long-ranged potential with three different strengths. For each of these systems we first determine the wetting properties occurring at a planar wall, including any wetting transition and the dependence of the contact angle on temperature. The hard wall corner is completely filled by vapour on approaching bulk coexistence and the numerical results for the growth of the meniscus thickness are in excellent agreement with effective Hamiltonian predictions for the critical exponents and amplitudes, at leading and next-to-leading order. In the presence of the attractive wall-fluid interaction, the corresponding planar wall-fluid interface exhibits a first-order wetting transition for each of the interaction strengths considered. In the right angle wedge geometry the two strongest interactions produce first-order filling transitions while for the weakest interaction strength, for which wetting and filling occur closest to the bulk critical point, the filling transition is second-order. For this continuous transition the critical exponent describing the divergence of the meniscus thickness is found to be in good agreement with effective Hamiltonian predictions.
Permanent Link: http://hdl.handle.net/11104/0231777