MACROSCOPIC EVIDENCE OF THE EFFECT OF INTERFACIAL SLIPPAGE ON ADHESION

The adhesion strengths of a viscoelastic adhesive were measured on var ious substrates that were prepared by grafting silanes bearing organic functional groups to silicon wafers. Conventional theories predict th at adhesion should be proportional to the surface free energy of the s ubstrate; but adhesion on a fluorocarbon surface was significantly gre ater than on some of the hydrocarbon surfaces, although the fluorocarb on surface has the lowest surface free energy. This result could be ex plained by invoking a model of adhesion based on the slippage of the a dhesive at the interface.