Effect of rings stiffness and steric interactions on the static and dynamics of linear catenanes

Using molecular dynamics, we study how the bending rigidity of the constituent rings affects the static and dynamics of isolated, interacting, and spatially-confined linear catenanes. For the isolated case, we show that stiffer rings yield catenanes with a more flexible backbone and slower relaxation dynamics at all length scales. We rationalize the results by separating the contributions of rings' shape and steric interactions to the backbone rigidity and by comparing the properties of (mechanically-bonded) catenanes to those of equivalent (covalently-bonded) polymers. We next consider the diffusivity of interacting catenanes, which is strongly impacted by rings' rigidity, even in the semi-dilute case. Finally, we turn to catenanes in spatial confinement and discuss how their morphology and relaxation dynamics respond to the degree of confinement.