Eur. Phys. J. E (2009) 29: 423-429
https://doi.org/10.1140/epje/i2009-10495-5

Regular Article

Scaling exponents of forced polymer translocation through a nanopore

¹ Department of Physics, University of Central Florida, 32816-2385, Orlando, FL, USA
² Department of Applied Physics, Helsinki University of Technology, P.O. Box 1100, FIN-02015 TKK, Espoo, Finland
³ Department of Physics, Brown University, Box 1843, 02912-1843, Providence, RI, USA
⁴ Institute of Physical Chemistry, Bulgarian Academy of Sciences, Georgi Bonchev Street, Block 11, 1113, Sofia, Bulgaria
⁵ Institut für Physik, Johannes Gutenberg Universität Mainz, Staudinger Weg 7, 55099, Mainz, Germany

^* e-mail: aniket@physics.ucf.edu

Received: 13 February 2009
Revised: 2 June 2009
Accepted: 13 July 2009
Published online: 8 August 2009

Abstract

We investigate several properties of a translocating homopolymer through a thin pore driven by an external field present inside the pore only using Langevin Dynamics (LD) simulations in three dimensions (3D). Motivated by several recent theoretical and numerical studies that are apparently at odds with each other, we estimate the exponents describing the scaling with chain length (Nof the average translocation time , the average velocity of the center of mass , and the effective radius of gyration during the translocation process defined as , , and respectively, and the exponent of the translocation coordinate (s -coordinate) as a function of the translocation time . We find , for and for , , and , where is the equilibrium Flory exponent in 3D. Therefore, we find that is consistent with the estimate of . However, as observed previously in Monte Carlo (MC) calculations by Kantor and Kardar (Y. Kantor, M. Kardar, Phys. Rev. E 69, 021806 (2004)) we also find the exponent α = 1.36 ± 0.01 < 1 + ν. Further, we find that the parallel and perpendicular components of the gyration radii, where one considers the “cis” and “trans” parts of the chain separately, exhibit distinct out-of-equilibrium effects. We also discuss the dependence of the effective exponents on the pore geometry for the range of N studied here.