WasserinÖl

WasserinÖl, commonly referred to in English as water-in-oil (W/O) emulsions, are emulsions in which water droplets are dispersed within a continuous oil phase. In these systems, the dispersed phase is aqueous, while the surrounding matrix is oil, making the emulsion more viscous and occlusive than many oil-in-water counterparts.

W/O emulsions are stabilized by lipophilic surfactants and sometimes co-surfactants that reside at the water–oil interface. Typical stabilizers include sorbitan esters and other oil-soluble emulsifiers, as well as natural phospholipids or waxy substances found in the oil phase. The choice of oil (mineral oil, ester oils, silicone oils, or natural oils) and the water content determine the texture, opacity, and stability of the system. Water content can be high in some formulations, producing high internal-phase emulsions with gel-like rheology.

Applications of WasserinÖl span cosmetics, pharmaceuticals, and industrial formulations. In cosmetics, water-in-oil creams and lotions are valued for their occlusiveness and barrier protection, particularly for dry or sensitive skin. In pharmaceuticals, W/O emulsions serve as topical dosage forms and sustained-release vehicles. Industrially, water-in-oil emulsions occur in lubricants, drilling fluids, and some metalworking fluids, where the oil phase provides lubrication while small water droplets modulate cooling and viscosity. Butter and certain margarines are natural W/O emulsions, formed by churning cream to disperse water droplets in fat.

Stability considerations include coalescence, Ostwald ripening, and phase inversion, which can occur if water content or temperature changes significantly. Characterization methods include microscopy for droplet size, rheometry for flow behavior, and phase-diagram analysis to predict inversion points. WasserinÖl remains an important class of emulsions across science and industry.