Foams based on biosurfactant mixtures. Part II. Influence of mixture composition on foam stability

This paper reviews the literature on various biosurfactant mixtures used to obtain foams. The interactions between different biosurfactants, biosurfactants and synthetic surfactants, biosurfactants' interactions with various additives (as non-surface-active macromolecules or particles) and the impact of pH and ionic strength variations on adsorption processes, foamability, foam stability and rheology are discussed. Biosurfactants are natural and synthetic compounds that can facilitate the process of foam formation and stabilisation; they are an alternative to classical surfactants. Research on such materials will allow the development of innovative foaming technologies that minimise the negative environmental effects of foaming compounds without losing the properties of the final product.