Properties of liquid foams stabilized by sugar-based surfactants and prepared under different conditions

Abstract

The study of foam stability is a subject of continuous research, due to the different fields of application foams are used in. In this study, foams stabilized with a family of nonionic sugar-based surfactants were investigated systematically. For this purpose, we changed the concentration (c > cmc), the gas flow rate, and the disk porosity. The foam properties were evaluated by measuring the foam volume, the liquid fraction, and the bubble size distribution as a function of time. We observed good foamability for all conditions tested with a tendency towards increasing stability with increasing chain length and increasing head group size. For foams stabilized by the short chain surfactants β-C₈G₁ and β-C₈G₂ we observed a significant time evolution due to coarsening and coalescence, while foams stabilized with the longer chain surfactants hardly changed during the observation time. From an industrial point of view, our study helps to understand properties of foams generated under different conditions. We conclude that for the special family investigated here a very good performance can be expected for a broad variety of conditions.