Evaluation of adhesive and elastic properties of polymers by the BG method

The work of adhesion and the elastic contact modulus of the pair of interacting materials are a prerequesite in order to study adhesive interactions between solids. For small material samples, the contact modulus is usually evaluated by depth-sensing indentation of sharp indenters, while the work of adhesion is determined by direct measurements of pull-off force of a sphere. These measurements are unstable due to the instability of the load–displacement diagrams under tension, and they can be greatly affected by the roughness of the contacting solids. Using experiments for polyvinylsiloxane samples, it is shown how the work of adhesion and the elastic contact modulus of materials may be quantified using the BG method. This is a non-direct method based on an inverse analysis of a stable region of the experimental force–displacement curves. The BG method is simple and robust. Nevertheless, the extracted values of both characteristics vary within the same polymer sample due to contact areas that possess interacting polymer molecules in various orientations. It was found that the average values of characteristics are very stable and the work of adhesion of polymers may be treated as a material parameter in statistical sense