Adhesion induced buckling of spherical shells

Deformation of a spherical shell adhering onto a rigid substrate due to van der Waals attractive interaction is investigated by means of numerical minimization of the sum of the elastic and adhesion energies. The conformation of the deformed shell is governed by two dimensionless parameters Cs/ε and Cb/ε, where Cs and Cb are respectively the stretching and the bending constants, and ε is the depth of the van der Waals potential. As a function of Cb/ε, we find both continuous and discontinuous buckling transitions for small and large Cs/ε, respectively, which is analogous to van der Waals fluids or gels. Some scaling arguments are employed to explain the adhesion induced buckling transition. (letter to the editor)