Lubrication with Emulsions
Résumé
Because oil has a different density than water, buoyancy causes the phases to separate, i.e., emulsions are inherently unstable. To add stability, emulsions are aggressively agitated to achieve very small droplet sizes and tight distributions, or emulsifiers are added to the system. Emulsifiers are usually surfactants, although some formulations use macromolecules, fine particles, and/or simple electrolytes as emulsifiers. An emulsifier is a long molecule with a polar end. One end of the molecule is soluble in oil, while the other prefers water ...