In previous work concerning fiber-matrix junctions in single-fiber composites, a linear relationship has been established between the interfacial shear strength tau and the reversible adhesion energy W at the interface, which takes into account dispersive and acid-base interactions. In the present study, the validity of such a relationship is examined from a theoretical paint of view. It appears that its mathematical form is entirely justified in terms of "static friction", if tau is considered as the resistance to the interfacial slipping due to the existence of molecular interactions. The mast important parameter in this approach appears to be the equilibrium intermolecular or interatomic distance lambda at the interface. It is shown, in good agreement with results available in the literature, that lambda decreases when the work of adhesion increases, in particular when strong acid-base interactions are involved at the interface. To a first approximation, it appears that the reversible work of adhesion W varies like lambda(-2). By analogy with the theoretical expression of the interaction energy between a fiber and an infinite matrix, a consistent value of the Hamaker constant for the given system was estimated. Moreover, a threshold intermolecular distance, beyond which no adhesion phenomena could be considered, is found equal to about 0.7 nm.