Toward a Direct Measurement of Paraffin Adhesion Forces

Abstract

In the present work, the interaction forces between paraffin surfaces and solid substrates were studied using an atomic force microscope (AFM). Approximation and retraction curves, called force curves, were measured at room temperature between the AFM probe and stainless-steel (SS) substrates with either of them uncoated or coated with a paraffin film. A great influence of the surface topography on the force curves was observed. This influence results in a large variation of the interaction force values obtained at different spots of the sample surface. For some of the spots, which are associated with large paraffin crystals or agglomerates, the force curves change each time a measurement is performed, apparently because of the deformation of the paraffin crystal. For some other spots, which seem to be related to thin paraffin layers, a reproducible behavior is observed, allowing for the estimation of the interaction force values. A considerable dispersion of the values of adhesion forces and jump-in and ...