Estudo da formação e estabilidade de espumas de tensoativos catiônicos com ênfase no mercado cosmético

Abstract

Foams are colloidal systems formed by gas in liquid, which require the presence of surfactants to become stable. The search for surfactants capable of producing foam and still promoting a gentle cleansing of the scalp and hair led to the analysis of cationic surfactants. The surfactants used mostly present quaternary nitrogen. Two known commercial surfactants (cocoamidopropyl betaine and sodium lauryl ether sulfate) were also used for comparison purposes. The formation and stability of foams were the focus of this study, evaluated through two foam formation methods – Bartsch method and agitation, foam volume and drainage monitoring method (Henkel corp.) – and two tensiometry methods – du Nöuy ring method and pendant drop method –. The surfactants were evaluated in dilutions commonly used at the time of application of the shampoo, in the original concentration and also in mixtures of the best cationic surfactant with other surfactants. The results showed that cationic surfactants have viability as foaming agents, and lauramine oxide was highlighted for presenting results close to those obtained by sodium lauryl ether sulfate and cocoamidopropyl betaine, showing the possibility of its use in this niche of the cosmetic market.