Foam measurement by the microconductivity technique: An assessment of its sensitivity to interfacial and environmental factors

The foam microconductivity method was systematically evaluated to determine precisely what foam parameters were being measured, Foam liquid drainage profiles were measured to correlate the foam density with foam conductivity, This relationship was linear in the measurement region, The effect of salt concentration on the foam density/conductivity relationship was determined, a small effect was found at low concentrations for ionic surfactants. The bubble size distribution was measured and found to be very narrow and independent of surface tension, but dependent on orifice size, and limited by flow rate of the gas through the orifice, Finally, the foaming properties of the protein beta-lactoglobulin and the nonionic surfactant Tween20 were evaluated to demonstrate the sensitivity of the technique to changes in interfacial composition. (C) 1996 Academic Press, Inc.