A substance, called a surfactant, which intimately mixes, modifies the surface tension of colloidal
droplets, and disperses dissimilar materials that are ordinarily immiscible, such as oil and water,
to produce a stable emulsion. The emulsifier has the double task of promoting the emulsification
and stabilizing the finished product. [Painting/Coatings Dictionary] To accomplish this,
surfactants for water-borne coatings have a hydrophilic (water-loving) group and a hydrophobic
(water-hating) group.
