Free Energy Barrier for Electric Field Driven Polymer Entry into Nanoscale Channels

TL;DR

This paper investigates the free energy barrier for a charged polymer entering a nanoscale channel under an electric field, combining theoretical analysis and molecular dynamics simulations to understand how various factors influence the entry process.

Contribution

It introduces a combined theoretical and simulation approach to analyze how electric field, polymer length, and channel geometry affect entry barriers, including the squeezing effect.

Findings

Barrier height depends on polymer length, electric field strength, and channel geometry.

Lateral confinement significantly alters the polymer length dependence of the barrier.

Theory and simulations agree well and match experimental data.

Abstract

Free energy barrier for entry of a charged polymer into a nanoscale channel by a driving electric field is studied theoretically and using molecular dynamics simulations. Dependence of the barrier height on the polymer length, the driving field strength, and the channel entrance geometry is investigated. Squeezing effect of the electric field on the polymer before its entry to the channel is taken into account. It is shown that lateral confinement of the polymer prior to its entry changes the polymer length dependence of the barrier height noticeably. Our theory and simulation results are in good agreement and reasonably describe related experimental data.