Interfacial Delamination of Inorganic Films on Viscoelastic Substrates

The performance of flexible/stretchable electronics may be significantly reduced by the interfacial delamination due to the large mismatch at the interface between stiff films and soft substrates. Based on the theory of viscoelasticity, a cracked composite beam model is proposed in this paper to analyze the delamination of an elastic thin film from a viscoelastic substrate. The time-varying neutral plane of the composite beam is derived analytically, and then the energy release rate of the interfacial crack is obtained from the Griffith's theory. Further, three different states of the crack propagation under constant external loadings are predicted, which has potential applications on the structural design of inorganic flexible/stretchable electronics.