Capillary theory of free fluid surfaces

Abstract

The traditional formulation of capillary theory does not explicitly contain the general dimension equation that is valid also for its own scalar variables. Its introduction enables the experimentally determinable physical properties to be interpreted. These properties individually characterize the bulk phases generating the layers that enter into the capillary interaction. Not only empirically known approximate relationships, such as the van der Waals and Walden equations, the Watson’s formula, and the Cailletet–Mathias rule, can be derived through them, but also new findings can be made. By extending the formulation with a new type of parameters, the relationships of temperature, density-dependence, etc. may be directly generated. The individual concept, which differs from the traditional theory in only one extra power law, is compatible with other capillarity methods based on material structure and outperforms the heuristic power of the traditional theory in terms of operability.