Interfacial Regulation by Surfactants in Spray Cosmetics: Mechanisms and Applications

Spray cosmetics couple formulation composition with actuator design and biological targets, so their performance is governed by rapid, nonequilibrium interfacial processes that cannot be predicted from in-bottle stability or equilibrium surface tension alone. This targeted narrative review integrates evidence across storage stability, atomization, droplet flight and evaporation, deposition, film formation, active delivery, inhalation safety and environmental fate. It examines how surfactant molecular structure, micellar replenishment, dynamic surface tension, interfacial viscoelasticity and extensional rheology influence droplet-size distributions, wetting, spreading and deposition. Particular attention is given to competing effects: enhanced breakup may increase airborne fine fractions; stronger interfacial films may impair sprayability; enhanced penetration may reduce barrier tolerance; and bio-based origin does not necessarily imply a lower life-cycle burden. Across moisturizing, sunscreen, hair- and scalp-care, makeup-setting, cleansing-foam and emerging functional sprays, this review develops an interface-to-outcome framework and a multiobjective operating-window concept linking formulation and device variables to efficacy, manufacturability, safety and sustainability. The available evidence supports product-specific, whole-process validation rather than optimization against any single equilibrium property, while highlighting the need for spray-relevant dynamic measurements, realistic exposure assessment and validated formulation–device co-design.