emulsi

Emulsi is a term used to refer to emulsions, which are mixtures in which one liquid is dispersed as droplets within another immiscible liquid. Emulsions are stabilized by emulsifiers or stabilizing agents that reduce interfacial tension and form a protective film around droplets to prevent coalescence. The two most common types are 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. More complex systems include multiple emulsions such as water-in-oil-in-water (W/O/W) and oil-in-water-in-oil (O/W/O).

Formation and stability

Emulsions form when two immiscible liquids are mixed with an emulsifier or stabilizer, often under high shear or homogenization to create small droplets. Droplet size, distribution, and the integrity of the interfacial film determine stability. Without stabilizers, droplets may coalesce and phase separation occurs. Other instability pathways include creaming or sedimentation due to density differences and Ostwald ripening. Stabilizers range from surfactants (for example lecithin, polysorbates) to proteins (such as casein or egg proteins), polysaccharides, polymers, and solid particles that yield Pickering emulsions.

Applications

Emulsions are widespread in food, cosmetics, pharmaceuticals, and industry. In food, mayonnaise, dressings, and dairy products rely on O/W emulsions. In cosmetics, creams and lotions use emulsions to deliver active ingredients. In pharmaceuticals, emulsions serve as drug delivery systems and topical formulations. Industrial uses include paints, coatings, lubricants, and bitumen emulsions.

Stability considerations

Formulators manage pH, ionic strength, temperature, and shear history to achieve desired stability or controlled destabilization, depending on the application.