Complexation between lignosulfonates and cationic surfactants and its influence on emulsion and foam stability

The association between sodium lignosulfonates and cationic as well as nonionic surfactants (quaternary ammonium bromides, cetylpyridinium chloride (CPC)) has been investigated by means of surface tension measurements, with additional information from measurements of viscosities and electrophoretic mobilities. A strong interaction is revealed between the lignosulfonate (LS) and micelles of the cationic surfactant, whereas no interaction is found in the case of a polyethyleneoxide-based nonionic surfactant. This is in agreement with the general behavior of polyelectrolyte-surfactant systems. LS as emulsifier in oil/water emulsions (o/w) gives rapid creaming into a highly concentrated emulsion, which is stable towards coalescence. The addition of cationic surfactant enhances the stability towards creaming. LS is a poor foaming agent, but the addition of cationic surfactant greatly improves the foam stability. (C) 1999 Elsevier Science B.V. All rights reserved.