Theoretical study on the translocation of partially charged polymers through nanopore

Abstract

The translocation time τ of partially charged polymers through a neutral nanopore is calculated using Fokker–Planck equation with adsorbing–adsorbing boundary conditions. For the polymer with one charged monomer, we find that τ is dependent on the position of the charged monomer and on the magnitude of the driving force f inside the nanopore. When the charge is located at the front half of the polymer chain, τ is larger than that of neutral polymer and increases with f. When the charge is located at the back half, it is smaller than that of the neutral polymer and decreases with increasing f. We have also studied the behavior of a symmetrical polymer with two like charges located symmetrically in the chain and that of an asymmetrical polymer with two unlike charges. Moreover, we have calculated the translocation time for a general condition of polymer with two randomly distributed charges. All results show that τ is dependent on the positions of charges in the polymer chain and on the magnitude of the driving force. The results can be explained qualitatively by the free‐energy landscape of polymer translocation. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 1017–1025