ABSTRACT
When a solid surface is examined either microscopically with a scanning electron microscope or mechanically with a surface profilometer, it is found to contain irregularities; that is, the surface is not flat and smooth. A depiction of a surface displaying these irregularities, or asperities as they are commonly called, is presented. A host of surface tools have been developed for the analysis and chemical characterization of surfaces. The interfacial bond strength is, with a few exceptions, stronger than the cohesive bonds of the cohesively weaker of the two solid surfaces, and when surface separation is attempted, fracture will occur not at the interface, but in the cohesively weaker material. The adhesion of polymers to metal surfaces is of interest with respect to both two-body and single-body adhesion, that is, where the polmyer is the adhesive. Polytetrafluoroethylene has an extremely low surface energy, is difficult to get to adhere to metal surfaces, and is, therefore, an ideal polymer for measuring adhesion to metals.
