Effect of Contact Deformations on the Adhesion of Particles

A strict theory of reciprocal influence of the contact deformation and molecular attraction of a ball and a plane has been developed. It has been shown that despite the van der Waals' forces being capable of increasing the elastic contact area between the ball and the plane, the force that is required to overcome the molecular forces arising when the contact is broken does not increase thereby. In fact, it remains equal to the attraction force value that is determined when considering the point contact of a nondeformed ball with a plane. In the absence of the electrostatic component, the adhesion force is equivalent to the first power of the ball radius and to the amount of work per unit area as required for effecting the equilibrium tearing-off of a flat surface of the same nature.