Widely varying measured values of three-phase line tension have been reported in the literature.  Experiments in solid-liquid systems are subject to uncertainty caused by surface roughness and heterogeneity.  These difficulties are avoided in liquid-liquid systems.

We report new measurements of the line tension of the dodecane-water-air system in the liquid lens configuration.  Improved experimental technique produced better axisymmetry and equilibrium of the lenses than in past experiments in our group.  Using a new image processing algorithm (TIFA-AI), the liquid-vapour interfaces were fit to solutions of the Laplace equation, rather than polynomials, as before.  Line tension of +1.11 μN was obtained for lens radii in the millimetre range.

We will discuss the interpretation of the data in terms of both the Neumann quadrilateral relation and an alternative, empirical formulation, which was derived from trends observed in the literature data.