Scaling exponents of Forced Polymer Translocation through a nano-pore

TL;DR

This study uses Langevin Dynamics simulations to analyze the scaling behavior of a homopolymer translocating through a nanopore under external driving, clarifying discrepancies in previous theoretical and numerical results.

Contribution

It provides detailed scaling exponents for translocation time, velocity, and radius of gyration, considering pore geometry effects, addressing conflicting prior findings.

Findings

Scaling exponents depend on chain length and pore geometry.

Finite pore size influences the velocity scaling exponent.

Pore geometry affects the translocation dynamics.

Abstract

We investigate several scaling properties of a translocating homopolymer through a thin pore driven by an external field present inside the pore only using Langevin Dynamics (LD) simulation in three dimension (3D). Specifically motivated by several recent theoretical and numerical studies that are apparently at odds with each other, we determine the chain length dependence of the scaling exponents of the average translocation time, the average velocity of the center of mass, $<v_{CM}>$, the effective radius of gyration during the translocation process, and the scaling exponent of the translocation coordinate ($s$-coordinate) as a function of the translocation time. We further discuss the possibility that in the case of driven translocation the finite pore size and its geometry could be responsible that the veclocity scaling exponent is less than unity and discuss the dependence of the scaling exponents on the pore geometry for the range of $N$ studied here.