FLUCTUATIONS IN THE STRUCTURE OF 3-PHASE LINES

We study the fluctuations in the density and composition of the contac t line at which three phases meet. The equilibrium structure of the co ntact line is obtained by minimizing a model free-energy functional an d then the fluctuations about that structure are analyzed via the spec trum of the free energy's second functional derivative. Three zero eig envalues correspond to three fluctuation modes in which the positions of the contact line and interfaces change with no change in their inte rnal structure. These eigenvalues are at the bottom of a continuum in which most of the corresponding fluctuation modes involve perturbation s in the structure of the interfaces, extending far from the three-pha se contact line. We identify one mode that is localized at the contact line and discuss its physical significance. (C) 1998 Elsevier Science B.V. All rights reserved.