Characterization of adhesion at solid surfaces: Development of an adhesion-testing device

A custom-built adhesion-testing device (ATD) is described in this paper, which was developed to study energetics of various solid (polymeric) interfaces. A review is also given of the main techniques of adhesion and adherence measurements, including non-destructive and destructive methods, with major emphasis on the evolution and applications of contact mechanics techniques. Using the Johnson-Kendall-Roberts (JKR) theory of contact mechanics in the elastic deformation regime, the interfacial energy of solid surfaces can be obtained by measuring the contact radius, loading force, and vertical displacement between an (elastic) sphere (lens) and a flat surface (one of which, or both, coated with the sample of interest). The parameters needed for JKR analyses were determined by our custom-built device. Based on the JKR theory, the values of work of adhesion, combined elastic modulus and interfacial energy were determined from the loading and unloading curves on poly(dimethylsiloxane)-poly(dimethylsiloxane) (PDMS) systems. Cumulative adhesion hysteresis and elastic modulus were also calculated. The results obtained agree well with literature data measured by different methods. These measurements on compliant PDMS-PDMS model systems can also serve as validation and verification of the adhesion-testing devices described in this study.