Adsorption kinetics of demulsifiers to an expanded oil-water interface

Relaxation of interfacial tension was recorded for the sudden expansion of a water droplet in the presence of a heptane or toluene solution of a number of demulsifier polymers prototypical of products used in industry to demulsify crude oil. Adsorption kinetics were found in all cases to be non-diffusion controlled. Increasing the polyoxyethylene content within the demulsifiers resulted in slower relaxation rates. This effect was much stronger in heptane than in toluene suggesting that polyoxypropylene-type polymers would be better candidates for demulsifying light, waxy crude oil emulsions.