Steering the potential barriers: entropic to energetic

TL;DR

This paper introduces a mechanism to control particle diffusion in narrow channels by adjusting the bias angle, transforming potential barriers from entropic to energetic, thereby optimizing transport properties.

Contribution

It presents a novel method to manipulate potential barriers in biased Brownian motion through bias angle adjustment, supported by analytical and simulation validation.

Findings

Optimal bias angle induces bell-shaped mobility behavior.

Effective diffusion coefficient can be tuned by bias angle.

Analytical predictions agree with Brownian dynamics simulations.

Abstract

We propose a new mechanism to alter the nature of the potential barriers when a biased Brownian particle under goes a constrained motion in narrow, periodic channel. By changing the angle of the external bias, the nature of the potential barriers changes from purely entropic to energetic which in turn effects the diffusion process in the system. At an optimum angle of the bias, the nonlinear mobility exhibits a striking bell-shaped behavior. Moreover, the enhancement of the scaled effective diffusion coefficient can be efficiently controlled by the angle of the bias. This mechanism enables the proper design of channel structures for transport of molecules and small particles. The approximative analytical predictions have been verified by precise Brownian dynamic simulations.