Effect of pH and particle size of ethyl cellulose dispersions on the foam stability in cosmetic formulations

Abstract

Foams stabilized only by surfactants were unstable. It is important to understand the properties of the foam and improve its stability. The aim of this study is to examine the effect of adding ethyl cellulose (EC) particles on the foam stability in the sodium dodecyl sulfate (SDS) solution. As a bio-compatible foam stabilizer, EC particles were prepared by an anti-solvent precipitation method for the pH and size control. The average size of EC NPs was synthesized from 197 nm to 502 nm for the size control and 280 nm for the pH control. The addition of EC dispersions enhanced the foam stability as the particle size increased and the pH lowered and suppressed bubble coalescence tendency by adsorption of EC NPs at the liquid-gas interface. For the SDS/EC dispersions with various sizes, the foam collapsing rate decreased from 6.44 mL/min of pure SDS solution to 3.91 mL/min. Additionally, in case of the SDS/EC dispersions with various pHs, a decreased foam collapsing rate up to 4.29 mL/min supported the foam stabilizing EC NPs. These results can be applied in personal care products with foaming ability.