Rate control of blister inflations and the skin patterns

Surface blistering is commonly observed in various biological processes such as cell apoptosis and locomotion. Despite the variety between systems, blister formation and growth are characterized by the delamination of a thin viscoelastic membrane from its substrate, followed by its large deformation (>100 %) as it is inflated by the infiltration of interstitial fluid. The dynamic of this process is controlled by three rates: the inflation rate, the skin’s viscoelasticity and the delamination rate. Through a combination of experiment and theoretical modeling, we find that competition between these time scales may trigger two instabilities, namely the membrane’s thinning instability and the delamination instability. Utilizing the interplay between these two mechanisms, we are able to control the equilibrium shape of a blister by simply mediating its inflation rate. These findings are then used to understand the surface blisters observed on thermo-sensitive hydrogels as they quickly deswell during their volume phase transition. By understanding the mechanism that governs the interplay between blister inflation and solvent transport, one can explain a diversity of skin patterns observed on the gel surface for different temperature and the gel’s crosslink density.