Spreading at the Metal/Oil/Water Interface.

A film balance method has been developed for measuring the pressures against which oil drops spread on metal surfaces. The pressure of a monomolecular film needed to just prevent the oil from spreading over the metal is related to the true spreading pressure at the oil on the metal. The theory and preliminary results of the technique for the system mineral oil-stainless steel-water are presented. The good agreement of the data with that reported for heptane on metals suggests that the film balance technique is capable of giving reliable data.