A Correction to this paper has been published: https://doi.org/10.1038/s42005-021-00523-5.
Stiffness gradients in geometrically confined polymers as measured by nanoindentation are influenced by opposing roles of the polymers viscoelastic state and the degree of confinement.
Moderately thick shells constrained in the radial and transverse directions buckle to a wavenumber set by a single geometric parameter.