Swell induced surface instability of confined hydrogel layers
A previous work suggested a critical condition to form surface creases in elastomers and gels. For elastomers, the critical condition seems to have closed a gap between experimental observations (e.g., by bending a rubber block) and the classical instability analysis by Biot. For gels, however, experiments have observed a wide range of critical swelling ratios, from around 2 to 3.7. Here we present a linear perturbation analysis for swollen hydrogels confined on a rigid substrate, which predicts critical swelling ratios in a similar range.
