emulgieren

Emulgieren, or emulsification, is the process of mixing two immiscible liquids to form an emulsion, a dispersed system in which droplets of one liquid are distributed within another. The most common pair is oil and water, but emulsions can involve other immiscible liquids. Emulsification is used in many industries, including food, cosmetics, pharmaceuticals, and materials science.

Emulsions are stabilized by emulsifiers, substances that adsorb at the liquid–liquid interface and reduce interfacial tension, creating a protective film around droplets to prevent coalescence. Stabilization can also be aided by increasing the viscosity of the continuous phase, using solid particles (Pickering emulsions), or by electrostatic or steric repulsion between droplets.

Two principal types exist: oil-in-water (O/W), where oil droplets are dispersed in water, and water-in-oil (W/O), where water droplets are dispersed in oil. A third category, multiple emulsions such as water-in-oil-in-water, exists for specialized applications. Emulsions vary in droplet size from micrometers to nanometers; stability depends on droplet size, emulsifier type, phase ratio, and processing history.

Common methods of emulsification include high-shear mechanical mixing, rotor-stator homogenization, high-pressure homogenization, and ultrasound; phase inversion can also produce emulsions. The choice of method depends on the desired droplet size and application.

Applications cover food products like mayonnaise and milk emulsions, cosmetics such as lotions and creams, pharmaceuticals for drug delivery, paints and coatings, and agrochemicals. Stability and quality control focus on preventing separation phenomena such as creaming, sedimentation, or coalescence over time.