Adhesion & Adhesives: Fundamental and Applied Aspects

Abstract

This chapter is a review of a laser-based adhesion testing experimental protocol to characterize the fracture toughness of the interface between a thin film and a substrate using a dynamic non-contact loading technique. Controlled dynamic delamination of thin film patterns from substrates is achieved using laser-induced stress pulses. The specimen geometry consists of a thin film pattern with an area of weak adhesion sandwiched between the thin film and substrate. A high-amplitude stress pulse generated on the backside of the substrate fails the weak adhesion region creating a pre-crack at the interface. The kinetic energy accumulated in the de-bonded portion of the thin film is subsequently channeled into the thin film-substrate interface leading to a controlled dynamic interfacial crack propagation. The thin film-substrate interface fracture toughness is determined by equating the kinetic energy to the fracture energy required for film delamination. This chapter also includes detailed parametric studies that help in understanding the effect of various experimental parameters on the kinetic energy available for interfacial dynamic crack propagation followed with a brief overview of numerical simulation that validates the experimental protocol.