A Novel Test for the Appraisal of Solid/Solid Interfacial Interactions

Abstract

The Johnson, Kendall and Roberts (JKR) technique has been used with considerable success for assessing solid/solid interfacial interactions over the past 25 years or so. Nevertheless, the contact zone between the two spherical solids is often small and the energy of adhesion scales with the cube of the contact radius (at low load), thus potentially magnifying errors in adhesion assessment. The theoretical aspects of a novel technique are presented here, in which a hollow, slightly inflated, spherical membrane replaces a full sphere, and is placed in contact with a flat rigid solid. A judicious choice of experimental conditions should lead to increased contact radius and the energy of adhesion scales with its square (at low load), thus reducing possible errors. An added advantage is that the effective elasticity of the sphere depends on internal gas pressure. Thus surface and bulk effects are decoupled.

Key Words:

• Adhesion hysteresis
• “balloon” test
• contact mechanics
• elastomer
• JKR test
• membrane
• spherical surface
• van der Waals adhesion