Ejection Dynamics Of A Semiflexible Polymer Out Of A Nanochannel

Using theoretical analysis and three-dimensional Langevin dynamics simulations, we investigate the influences of chain rigidity on the ejection dynamics of polymers from a nanochannel.We find that there exist two distinct dynamical regimes divided by a critical chain length for both flexible and semiflexible chains. The trends described in the escaping dynamics with different stiffness of polymer chains are similar and there are a maximal value of ejection time and a critical length which the ejection time is independent of the length. At the short chain regime, semiflexible chains eject faster than flexible chains of the same chain length due to the longer occupying length. In contrast, at the long chain regime, semiflexible chains eject slower than flexible ones as the effective entropic driving force decreases.We also show that the maximum of ejection time τmax scales as hv with the scaling exponent v approximately 3. But it has a slight decline due to the increase of the time spending in the driven process for semiflexible chain. Moreover, due to the high bending energy cost, the accumulation of rigid chain around the exit of the tube becomes difficult relatively. Therefore, the hypothesis that segments outside the nanochannel are not affected by friction is no longer valid. It leads to a slight decrease of the scaling exponent v of τlong with channel height hvBased on these results, we propose that the nanochannels could be used to separate flexible and semiflexible chains effectively.