Effect of Alkyl Tail Length of Alpha Olefin Sulfonates on Foam Properties

Abstract The effect of alkyl tail length on the foam properties of alpha olefin sulfonates (AOS) in aqueous solutions at various concentrations was investigated by measurements of the foamability, foam stability and bubble size and numbers, obtained from conductivity and image analyses techniques based on FoamScan foam analyzer. It was found that foamability and foam stability of C n AOS (n = 14–16, 16–18, 20–24) first increase and then decrease with increase in the carbon chain length, showing an optimum for a length of n = 16–18. The foamability and foam stability of AOS increase with increasing of surfactant concentration. This is due to the fact that the adsorbed quantity of surfactant molecules increases at the air/water interface with the increase of concentration. In addition, it was found that the bubble size produced by C 16–18 AOS is smaller than that of C 14–16 AOS.