AbstractThe morphology of surfaces produced during peel experiments was studied to increase the understanding of peel phenomena. Thin films of polystyrenes of narrow molecular‐weight distribution and a polydisperse polyester on flexible supports were peeled from rigid substrates at temperatures above their glass transitions with equipment that also permitted quenching and preservation of the peeled surfaces which then could be studied by scanning electron microscopy. The results show many types of cavitation including foams and the coalescence of cavities to form fibers. Cavitation occurred throughout and beyond the region of transition from cohesive to interfacial failure where peel force decreased abruptly; however, cavity growth was abruptly restricted as the failure mode changed. The master curves and shift factors obtained in this work provided strong evidence that the quenching used to preserve the peeled surfaces did not introduce large perturbations in the results. The reason was that failure occurred at or close to the heated substrat