Wrinkling of stimuloresponsive surfaces: mechanical instability coupled to diffusion

In this Letter, we propose a new mechanism to generate wrinkled patterns, based on the coupling between molecular diffusion and the buckling instability of rigid membranes "glued" on a polymer layer. The geometry of the diffusion front and the minimization of wrinkling energy conspire to generate various patterns of folds (e.g., parallel or radial folds, herringbone) and various dynamics (continuous or discrete). The diffusion process gives us the opportunity to study the stability of the various wrinkled patterns and to follow the creation or annihilation of topological defects.