Driven polymer translocation through nanopores: Slow-vs.-fast dynamics

¹  Physics Department, Technical University of Munich - D-85748 Garching, Germany, EU
²  Department of Polymer Science and Engineering and CAS Key Laboratory of Soft Matter Chemistry University of Science and Technology of China - Hefei, Anhui 230026, China
³  Department of Applied Physics and COMP Center of Excellence, Helsinki University of Technology P.O. Box 1100, FIN-02015 TKK, Espoo, Finland, EU
⁴  Department of Physics, Brown University, P.O. Box 1843, Providence, RI 02912, USA

Corresponding author: luokaifu@gmail.com

Received: 27 August 2009
Accepted: 25 November 2009

Abstract

We investigate the dynamics of polymer translocation through nanopores under external driving by 3D Langevin Dynamics simulations, focusing on the scaling of the average translocation time  vs. the length of the polymer, . For slow translocation, i.e., under low driving force and/or high friction, we find 1.588, where ν denotes the Flory exponent. In contrast, 1.37 is observed for fast translocation due to the highly deformed chain conformation on the trans side, reflecting a pronounced non-equilibrium situation. The dependence of the translocation time on the driving force is given by τ ~ F^-1 and τ ~ F^-0.80 for slow and fast translocation, respectively. These results clarify the controversy on the magnitude of the scaling exponent α for driven translocation.