Crack propagation along polymer/non-polymer interfaces

Mechanisms of the propagation of crack fronts along interfaces between a glassy polymer and metal or glass are discussed. Specifically, the systems studied are Poly-Ethylene Terephthalate (PETG) spin-coated on A1, PETG-glass and PETG hot-pressed on Cr-sputtered glass. Cracks studied propagate in an Assymetric Double Cantilever Beam (ADCB) geometry. Dependence of microscopic crack front geometry on propagation speed is found. The local stress state is found to have an impact on macroscopic as well as microscopic crack front geometry. Simple lattice model calculations of propagating crack fronts illustrate the impact of disorder and residual stress state on propagation mechanisms and macroscopic crack front shape respectively.