On the Adhesion between Individual Particles

Abstract

A dream in powder technology is to predict the structure and flow of a powder from precise knowledge of the interactions between the particles. The most important interaction is adhesion. In this paper several aspects of adhesion are discussed. First, the influence of humidity and capillary forces is analyzed. To calculate capillary forces the structure of the microcontact needs to be known with an accuracy much better than 1 nm. Determining the structure of a microcontact with such resolution is demanding, if possible at all. Considering that wear can lead to a change of the atomic structure such knowledge is practically impossible. Second, the work to break an adhesive contact depends on the effective spring constant by which the force is applied. Third, adhesion forces depend on the separation speed and not only the surface chemistry and the structure of the particles in the contact region. Fourth, we suggest to distinguish between contact and bridging adhesion.

Keywords

• granular matter
• powder particles
• capillary force
• surface energy
• work of adhesion
• dynamic force spectroscopy
• polymer
• bridging adhesion