lémulsification

Lémulsification is the process of forming an emulsion by dispersing droplets of one liquid in another immiscible liquid, typically with the help of an emulsifying agent. The goal is to reduce interfacial tension and create a metastable mixture that remains dispersed long enough for its intended use. Mechanical energy—stirring, blending, homogenization—facilitates droplet breakup and distribution.

Emulsions are classified by the continuous phase: oil-in-water (O/W) or water-in-oil (W/O). Emulsifier selection and concentration, phase ratio, and viscosity influence stability. Common stabilizers include surfactants (eg, nonionic, anionic), proteins (eg, casein), polysaccharides, and solid particles (Pickering emulsions) that form a barrier against coalescence.

Industrial and domestic production uses high-shear mixers, rotor-stator devices, high-pressure homogenizers, and ultrasonic devices to generate fine droplets. Applications span food (dressings, mayonnaise), cosmetics (creams, lotions), pharmaceuticals (drug delivery emulsions), and agrochemicals. The choice of method affects droplet size distribution, texture, and stability.

Stability is challenged by creaming, coalescence, Ostwald ripening, and phase inversion. Emulsions are thermodynamically metastable; stabilization strategies seek to minimize interfacial tension and create robust interfacial films. Temperature, pH, salinity, and aging also influence emulsion behavior.