The interaction between a liquid and a solid surface is the key to understanding wetting phenomena. A very large number of natural and industrial processes rely on the delicate manipulation of this interaction. Controlled wetting is of central importance in microfluidics, mineral flotation, high speed coating, electronic display technologies, oil recovery, lubrication, and plant protection.

At the molecular level, one can alter the distribution and charge of surface groups on functional surfaces, vary the number of hydrogen bonds, change molecular configuration, perform chemical grafts, and so forth. External stimuli such as light, electric potential, and heat can lead to subtle control of wettability, which is based strictly on thermodynamics.