FOAM MEASUREMENT BY THE MICROCONDUCTIVITY TECHNIQUE - AN ASSESSMENT OF ITS SENSITIVITY TO INTERFACIAL AND ENVIRONMENTAL-FACTORS

The foam microconductivity method was systematically evaluated to dete rmine precisely what foam parameters were being measured, Foam liquid drainage profiles were measured to correlate the foam density with foa m conductivity, This relationship was linear in the measurement region , The effect of salt concentration on the foam density/conductivity re lationship was determined, a small effect was found at low concentrati ons for ionic surfactants. The bubble size distribution was measured a nd found to be very narrow and independent of surface tension, but dep endent on orifice size, and limited by flow rate of the gas through th e orifice, Finally, the foaming properties of the protein beta-lactogl obulin and the nonionic surfactant Tween20 were evaluated to demonstra te the sensitivity of the technique to changes in interfacial composit ion. (C) 1996 Academic Press, Inc.