Interfacial rate processes in adhesion and friction

Adhesion between solid materials results from intermolecular interactions. The fracture resistance of an adhesive joint is, however, determined jointl y by the mechanical deformation in the bulk material and the strength of th e interfacial bond. The force needed to break an interfacial bond does not have a fixed value; it depends on the thermal state of the system and the r ate at which the force is transmitted to the bond, The concomitant energy d issipation arising from the extension and the relaxation of the interfacial bonds contributes a significant resistance to fracture, which is clearly e vident in elastomeric polymers. This issue of interfacial dissipation and i ts relationship to the length of the interfacial bridges and the rate of cr ack propagation are addressed with the kinetic theory of bond rupture in th e tradition of the models developed by Eyring, Tobolsky, Zhurkov, Bueche, S challamach, Kausch, and more recently, by Evans and Ritchie, Next, the meth od is extended to address the velocity-dependent sliding friction of elasto mers against low energy solid surfaces. The theme of this article is to poi nt out that certain aspects of adhesion, friction, and fracture may be desc ribed under a generalized framework of interfacial kinetics.