ABSTRACT
The reversible work of adhesion (W) is the free energy change per unit area in creating an interface between two bodies (Fig. 1). The work W is related to the intermolecular forces that operate at the interface between two materials, e.g., an adhesive and an adherend. However, in practice, the reversible work of adhesion may be obscured by other factors (e.g., mechanical interlocking, interdiffusion) because it is always a few orders of magnitude lower than the measured adhesive joint strength [1,2]. One important contribution to practical joint strength is the energy loss due to irreversible deformation processes within the adhesive. Nevertheless, Gent and Schultz [3] showed using peel strength measurements that viscoelastic losses were proportional to the reversible work of adhesion. For this reason, one of the important tasks is to determine the nature of interfacial chemical and physical forces and to understand how they control the reversible work of adhesion.
