Waterolie

Waterolie is a term used in some contexts to denote water-in-oil emulsions, where droplets of water are dispersed within a continuous oil phase. In such emulsions, interfacial stabilizers such as surfactants, colloidal particles, or polymers form a protective layer around water droplets, helping to prevent coalescence. The oil is the continuous phase, and water is the dispersed phase; this contrasts with oil-in-water emulsions, where water is the continuous phase.

Preparation and stabilization rely on selecting emulsifiers with suitable hydrophilic-lipophilic balance and applying sufficient energy through mixing. Methods such as high-shear homogenization and phase inversion temperature techniques are commonly used. Water-in-oil droplets can vary in size from submicron to several micrometers, and stability depends on the chosen oil phase, stabilizer system, and formulation conditions.

Properties of water-in-oil emulsions tend to include higher viscosity and a more occlusive feel, which can influence texture and application in finished products. Their rheology is often tailored to achieve desired spreadability and skin or surface retention.

Applications are prominent in cosmetics and personal care, where water-in-oil emulsions are used in creams and ointments to provide occlusion and moisture retention. They also appear in certain pharmaceutical topical formulations. In food science, water-in-oil systems are less common than oil-in-water emulsions but can be found in specific fat-rich spreads or confectionery fillings, depending on the product design.

Stability considerations include the risk of phase separation, coalescence, or Ostwald ripening, which are mitigated by selecting appropriate emulsifiers, oil phases, and additives. Temperature changes can trigger phase inversion, altering the emulsion type. The term waterolie may appear in Dutch-language literature as shorthand for water-in-oil emulsions, with English-language literature typically using water-in-oil emulsion.