(609a) Nanostructured Surfaces: Their Effect on Adhesion and Friction

We have carried out experiments on the effects of surface texture on adhesion and friction forces. The systems include both biological and non-biological surfaces, with structures ranging from the nano- through the micro- to the macro-scales. Various types of surface textures were studied, including randomly rough surfaces, regularly patterned surfaces, surfaces with nanoparticles on them, and natural biological surfaces. In some cases we studied the relationship and synergy between adhesion and friction forces. Our results show that textured surfaces can exhibit very complex behavior, including qualitatively new features that are not found with smooth (unstructured) surfaces, including such effects as load-dependent adhesion (hysteresis in loading-unloading cycles) and time-dependent effects. The greater variety of surface interactions offerred by textured surfaces makes them promising candidates for fabricating new types of surfaces with a wide variety of static and dynamic adhesion and tribological properties.