Buckling of stiff polymer rings in weak spherical confinement

Confinement is a versatile and well-established tool to study the
properties of polymers either to understand biological processes or
to develop new nanobiomaterials. We investigate the conformations
of a semiflexible polymer ring in weak spherical confinement
imposed by an impenetrable shell. We develop an analytic argument
for the dominating polymer trajectory depending on polymer
flexibility considering elastic and entropic contributions. Monte
Carlo simulations are performed to assess polymer ring
conformations in probability densities and by the shape measures
asphericity and nature of asphericity. Comparison of the analytic
argument with the mean asphericity and the mean nature of
asphericity confirm our reasoning to explain polymer ring
conformations in the stiff regime, where elastic response prevails.