AXISYMMETRICAL ADHESION TESTS OF SOFT MATERIALS

We describe a general, linearized fracture mechanics analysis for stud ying the adhesive properties of elastic, low modulus materials. Severa l adhesion tests are described, but all involve an elastic material wh ich is brought into contact with a rigid surface along an axis of radi al symmetry. Relationships between the load, displacement, and radius of the circular contact area between the two materials are described. These relationships involve the elastic modulus of the compliant mater ial, the energy release rate (or adhesion energy) and various paramete rs which characterize the geometry of interest. The ratio of the conta ct radius to the thickness of the elastic material is shown to be a pa rticularly important parameter. After reviewing some general concepts relevant to the adhesion of soft polymeric materials, we describe the fracture mechanics analysis, and provide examples from our own work on the adhesion of elastomers, thermoreversible gels and pressure sensit ive adhesives.