Foaming binary solution mixtures of low molecular surfactant and polyelectrolyte

Abstract

The lifetime of water solution foams of sodium dodecylsulfate (DDS, low molecular weight surfactant) and sodium carboxymethylcellulose (SCMC, polyelectrolyte) and their binary mixtures was experimentally investigated. The effects of ionic strength and acidity on the foam life were also determined. In binary solutions, a synergic effect of DDS and SCMC on the surface tension reduction, most likely resulting from the interaction of the surfactant with polymer, was found. The addition of NaCl into solution or increasing the ionic strength was found to decrease the surface tension and reduce interfacial mobility, hence increased foam lifetime. The relatively low lifetime of binary solution foams in acidic medium was attributed to the reaction between SCMC and acid, which resulted in relatively small reductions in the viscosity and consequently lowered the solution viscosity.