Morphological Instability and Kinetics of an Elastic Film on a Viscoelastic Layer

This paper develops a theoretical model for wrinkling of an elastic film on a viscoelastic layer. The film is elastic and subjected to a compressive residual strain. The viscoelastic layer is sandwiched between the film and a rigid substrate. The nonlinear von Karman plate theory is employed to model the film, and a thin-layer approximation is adopted for the viscoelastic layer. The stability of the system and the kinetics of structural evolution are studied first by a linear perturbation analysis and then by numerical simulations, both for plane strain deformation only. Three stages of evolution are identified: initial growth of the fastest growing mode, intermediate growth with mode transition, and finally an equilibrium wrinkled state. The results qualitatively agree with experimental observations of wrinkling in metal/polymer bilayer films.