Formation and Performance of Cosmetic Films in Cosmetics

Many cosmetic topical products rely on the formation of a film or coating on the surface of hair or skin. Depending on the way they are formed their morphological and chemical characteristics must be optimized so that the final function (shampoo, make up, etc.) can be achieved. This requires not only to understand the physicochemical characteristics of a formula but also how the film-forming ingredients interact with the substrate. Using the examples of shampoo, lipstick or foundation, we show here the different scientific aspects considered when developing a formula, from the formation of thin films (via the precipitation of polymer-surfactant aggregates) to the sensorial evaluation of the consumer. This short chapter shows different examples of technologies of pertinence when developing performing coatings. This is particularly important nowadays as cosmetic companies are in the process of incorporating new natural ingredients that also contribute reducing the environmental impact of a cosmetic formula while preserving its physicochemical properties.