Controlling the order of wedge filling transitions: the role of line tension
By: J. M. Romero-Enrique
From: Universidad de Sevilla, Spain
At: Complexo Interdisciplinar, Anfiteatro
[2007-07-11]
We study filling phenomena in 3D wedge geometries paying particular attention to the role played by a line tension associated with the wedge bottom. Our study is based on transfer matrix analysis of an effective one dimensional model of 3D filling which accounts for the breather-mode excitations of the interfacial height. The transition may be first-order or continuous (critical) depending on the strength of the line tension associated with the wedge bottom. Exact results are reported for the interfacial properties near filling with both short-ranged (contact) forces and also van der Waals interactions. For sufficiently short-ranged forces we show the lines of critical and first-order filling meet at a tricritical point. This contrasts with the case of dispersion forces for which the lines meet at a critical end-point. Our transfer matrix analysis is compared with generalized random-walk arguments based on a necklace model and is shown to be a thermodynamically consistent description of fluctuation effects at filling. Connections with the predictions of conformal invariance for droplet shapes in wedges is also made.
[1] J. M. Romero-Enrique and A. O. Parry, J. Phys.: Condens. Matter vol. 17,
S3487 (2005)
[2] J. M. Romero-Enrique and A. O. Parry, Europhys. Lett. vol. 72, 1004
(2005).
[3] J. M. Romero-Enrique and A. O. Parry, New Journal of Physics vol. 9, 167
(2007).