Jamming of semiflexible polymers

Abstract

We study jamming in model freely rotating polymers as a function of chain length $N$ and bond angle $\theta_0$. The volume fraction at jamming, $\phi_J(\theta_0)$, is minimal for rigid-rod-like chains ($\theta_0 = 0$), and increases monotonically with increasing $\theta_0 \leq \pi/2$. In contrast to flexible polymers, marginally jammed states of freely rotating polymers are highly hypostatic, even when bond and angle constraints are accounted for. Large aspect ratio (small $\theta_0$) chains behave comparably to stiff fibers: resistance to large-scale bending plays a major role in their jamming phenomenology. Low aspect ratio (large $\theta_0$) chains behave more like flexible polymers, but still jam at much lower densities due to the presence of frozen-in 3-body correlations corresponding to the fixed bond angles. Long-chain systems jam at lower $\phi$ and are more hypostatic at jamming than short-chain systems. Implications of these findings for polymer solidification are discussed.