An emulsifier is a type of surfactant typically used to keep emulsion (mixtures of immiscible fluids) well dispersed. Emulsifiers typically have a hydrophobic (water-hating) and a hydrophilic (water-liking) end. The emulsifiers will surround an oil (or other immiscible molecule) and form a protective layer so that the oil molecules cannot "clump" together. This action helps keeps the dispersed phase in small droplets and preserves the emulsion.