emulsionen

An emulsion is a mixture of two immiscible liquids in which one liquid is dispersed as droplets within the other. The dispersed phase and continuous phase are typically water and oil; emulsions are often stabilized by emulsifiers such as surfactants, proteins, or gums, and by mechanical energy during mixing. Note: in German, the plural is Emulsionen.

Common types include oil-in-water (O/W) emulsions, where oil droplets are dispersed in water (e.g., milk, salad dressings), and water-in-oil (W/O) emulsions, where water droplets are dispersed in oil (e.g., butter, some cosmetic creams). Multiple emulsions such as water-in-oil-in-water (W/O/W) exist.

Emulsions are thermodynamically unstable; they tend to separate over time due to coalescence, creaming or Ostwald ripening. Stabilization reduces interfacial tension and creates steric or electrostatic barriers. Emulsifiers, surfactants, proteins, and polymers are used.

Production often uses homogenization, high-shear mixing, or ultrasonic devices to create small droplets. The droplet size, phase ratio, and viscosity influence stability and texture.

Applications include foods (dressings, mayonnaise, dairy), cosmetics (creams, lotions), pharmaceuticals (drug delivery, ointments), and industrial products (paints, lubricants). In microemulsions and nanoemulsions, the droplets are in the nanometer range and stability is enhanced.