Microscopic aspects of crack propagation along PET–glass and PET–Al interfaces

This paper reports microscopic investigations of the propagation of cracks along polymer–glass and polymer–metal interfaces. The experimental methods include an asymmetric double cantilever beam in an optical microscope, and birefringence and atomic force microscopy of the crack faces. The crack fronts propagate inhomogeneously in space and time by way of forward bursts that spread laterally along the front over a certain distance. Experimental indications for correlation between crack propagation and interface roughness and for the occurrence of shear-bands in front of the propagating interface cracks are discussed.