2001 Volume 19 Pages 131-143
Many studies have been made on the theoretical and practical aspects of the several adhesion forces which determine the properties of bulk solids of fine and finest particles. The aim of this work is the defined modification, especially minimisation, of the adhesion forces measured at the model adhesion system sphere-plate by the centrifuge method and AFM. The sphere diameter, surface roughness and chemical surface properties were varied in a controlled manner. In the observed diameter region (several nanometres to several tens of micrometres) and ambient conditions (25 to 80% relative humidity), the adhesion can be described as a combination of van der Waals forces and capillary forces according to well-known theories 1, 2). Because of the combination of the force spectroscopy with the imaging of surface topography in atomic force microscopy (AFM), it is possible to interpret measured forces as a function of the locally resolved curvature of the surface, which can be influenced by cleaning or etching procedures and surface modification or deposition, respectively.
