mikroemulsio

Mikroemulsio, commonly known as a microemulsion, is a thermodynamically stable, isotropic dispersion of oil and water stabilized by a surfactant system that often includes a cosurfactant. Droplet sizes are typically in the range of 10 to 100 nanometers, giving the dispersion a clear or translucent appearance.

It forms spontaneously under appropriate composition and temperature, in contrast to conventional emulsions that require external energy. The stability arises from a favorable balance of interfacial tension, curvature elastic energy, and entropy, aided by a relatively high surfactant load.

Microemulsions can be oil-in-water (O/W), water-in-oil (W/O), or bicontinuous, where oil and water networks interpenetrate. They are described by ternary phase diagrams and are often categorized by Winsor types I, II, and III, with type III representing bicontinuous middle-phase systems.

Common components are an oil phase, a water phase, a surfactant (typically nonionic or ionic), and sometimes a cosurfactant such as short-chain alcohols or glycols. They exhibit ultralow interfacial tension and high solubilization capacity for hydrophobic substances, enabling extensive drug solubilization and delivery.

Applications span pharmaceuticals and cosmetics for improved solubility and dermal delivery, topical and transdermal formulations, food products, and environmental or industrial uses such as cleaning agents and enhanced oil recovery.

Advantages include thermodynamic stability and the possibility of low-energy preparation; drawbacks include relatively high surfactant content and potential irritation or toxicity, along with formulation sensitivity to temperature and composition.