Report on the influence of boundary surface forces at the boundaries of liquid phases regarding processes of liquid transport under zero gravity conditions

Literature on boundary surface forces and their effects on liquid transport processes was reviewed as an aid in planning zero-gravity experiments in space. The physics of boundary surfaces, wetting, contact angle, spreading, immersion, sinter processes, zone melting and coalescence are discussed. It is shown that liquid flow phenomena at two phase boundary surfaces can be caused by gradients of the boundary surface energy and that at three phase lines flow is caused by the boundary surface forces themselves.