Industrial & Engineering Chemistry Research, Vol.53, No.49, 18891-18899, 2014
Effects of Micellar Structuring and Solubilized Oil on the Kinetic Stability of Aqueous Foams
We investigated the kinetic stability of foams formed from surfactant aqueous micellar solutions of sodium dodecyl sulfate at two different micellar concentrations (0.06 and 0.03 M). We used the air-sparging method and the Bartsch shaking method to form foams in the absence and in the presence of oil solubilized in micelles. We also examined the foam stability by studying the stability of a single foam lamella and observed the effect of the micellar structuring phenomenon in the confines of the foam lamella on foam stability. Our results showed that the foam formed by the air-sparging method contained small bubbles with curved lamellae that were less polydisperse in size, whereas the foam generated by the Bartsch method had plane-parallel lamellae that were more polydisperse in size. The stability of the lamella affects the kinetic stability of the bulk foam formed by the two methods. The micellar structuring phenomenon tests using the single foam lamella revealed that the multilayering structure was well-pronounced in the absence of the solubilized oil; as a consequence, the foam lamellae thinned slowly layer-by-layer and the oil solubilized in micelles weakened the micellar structure formation. The foam lamellae thinned faster, making the foam less stable.