Three-phase contact line energetics from nanoscale liquid surface topographies

The contact line tension of a three-phase system (solid-liquid-vapor) is determined from the liquid surface topography data obtained with scanning force microscopy. The data are analyzed in two completely complementary ways, one of which is based on the modified Young equation, the other on the effective interface potential derived from the profile of the liquid-vapor interface in the three-phase region. The two methods agree quite well for the systems investigated. Contact line tensions are in the range of 10(-11) to 10(-10) J/m, which is consistent with theory.