Stabilization and Destabilization of Semiflexible Polymers Induced by Spherical Confinement

Spherical confinement can act either stabilizing or destabilizing on the collapsed state of a semi-flexible polymer. General free-energy arguments suggest that the order of the unconstrained collapse transition is the distinguishing factor: First order implies stabilization, second order causes destabilization. We confirm this conjecture by Monte Carlo simulations of a coarse-grained model for semiflexible polymers whose chain stiffness tunes the transition order. The resulting physical picture is potentially relevant for other systems under strong confinement such as proteins and DNA.