Materials cohesion and interaction forces

The most important methods to determine the cohesive interactions of materials and adhesive interactions between different substances are reviewed. The term cohesion is generalized as representing the unifying interaction forces of a single material and adhesion forces between different substances due to attraction. The aim is to interlink a number of frequently used interaction parameters in order to promote the understanding of materials research executed within different scientific (Material, Colloid, Sol-Gel and Nano) communities. The modern interdisciplinary research requires a removal of the historical obstacles represented by widely differing nomenclature used for the same material properties. The interaction parameters of different models are reviewed and representative numerical values computed from tabulated thermodynamic and spectroscopic material constants. The results are compared with published values. The models are grouped to represent single and two component systems, respectively. The latter group includes models for films on substrates and work of adhesion between liquids and solids. In most cases rather rough approximations have been employed, mostly relating to van der Waals substances for which the gas state is common reference state. In order to improve the predictability of the key Hamaker constant, a novel model for interpreting the dielectric spectrum is presented. The interrelation between thermodynamic, electronic. spectroscopic and dielectric parameters is illustrated by model calculations on typical inorganic materials of current interest as model compounds. The ionic solids are represented by NaCl and KCl, while ZnO, FeO, Fe2O3, Fe3O4, Al2O3, SiO2, TiO2, ZrO2, SnO, SnO2 represent ceramic oxides and semiconductors. The model compounds thus illustrate the effect of bond type (covalent or ionic) and valence (charge number and sign) of the constituent elements. However, since the focus is placed on a phenomenological analysis, the number of examples remains self-evidently incomplete. (c) 2008 Elsevier B.V. All rights reserved.