Assessing Adsorption of Conventional Friction Modifying Molecules by Relative Contact Potential Difference Measurements

Abstract

A contact potential difference device based on the vibrating capacitor method of Zisman (1932) was used to assess adsorption and film formation at metal-petroleum interfaces. Measurement of changes in contact potential due to material adsorbed on low surface area metallic substrates is an attractive and convenient method for obtaining information about the adsorbed layer such as the adsorption isotherm and energetics. The adsorption iostherms of methyl stearate, stearic, oleic, and elaidic acids on copper and steel have been determined by the vibrating capacitor method.