|
Capillary wave excitations on a flat fluid interface are a simple example
for a fluctuating Gaussian field in two dimensions. Capillary wave
correlations decay logarithmically, i.e. are very long-ranged, consequently one expects long-ranged fluctuation-induced forces between colloidal objects that are trapped at
a fluid interface. Depending on the boundary conditions of the interface height fluctuations on the surface of colloids, quite different long-range behavior of the fluctuation force appears. It ranges from 1/(d ln d) (for a pinned contact line and fixed colloid) to 1/d9
(free contact line and unconstrained colloid), where d is the distance between two colloids.
In contrast, the short-range behavior appears to be universal and strongly attractive [1].
Evidence for such a fluctuation interaction can be found in simulation results for the potential of mean force between nanoparticles at a liquid-vapor interface [2].
[1] H. Lehle, M. Oettel, S. Dietrich, EPL 75, 174 (2006). [2] H. Lehle, M. Oettel, F. Bresme, JCP 130, 214711 (2009). |
|