Chapter 3 - Surfaces and interfaces

Abstract

This chapter introduces the interfaces as boundaries between two immiscible phases, whose thickness and composition evolve in a complex way. The interface tension is introduced as a force per unit length and then as an energy per unit area. Both aspects enable a rigorous thermodynamic treatment as well as an intuitive vector analysis. Physical phenomena, such as capillary action, pressure in bubbles, wetting, are a direct effect of the action of interface tensions and are briefly introduced. Several case studies introduce the implications of the interfacial tension in technology. Interfacial tension greatly affects the life of the small insects, which make use of interface tension for propulsion, transport, hunting, or survival. On other habitable planets of different size than our own, some aspects of life, as we know it on Earth, would not be possible due to scaling aspects of the surface tension vs gravitation.