# Harnessing Entropic Effects from Interlayer Coupling to Modulate Ion Transport and Rectification in Multilayered Janus Graphene Nanopores

## TL;DR

This paper explores how ion transport and rectification can be enhanced in multilayered graphene nanopores through interlayer coupling and entropic effects.

## Contribution

The study reveals that interlayer coupling in multilayered Janus graphene oxide nanopores significantly enhances ionic current rectification through entropy-enthalpy competition.

## Key findings

- Multilayered Janus graphene oxide nanopores achieve a rectification ratio enhancement of up to 2 orders of magnitude.
- Interlayer coupling reshapes the free energy landscape, creating asymmetric profiles with multiple energy barriers and wells.
- Entropy plays a critical role in stabilizing energy wells and enabling directional ion transport in multilayer systems.

## Abstract

Ion transport through
nanoscale channels enables advanced
functionalities,
such as ionic current rectification (ICR), with promising applications
in neuromorphic computing and biomimetic signal processing. However,
the fundamental mechanisms controlling the ion dynamics under nanoconfinement
remain poorly understood. Using atomistic molecular dynamics simulations
and free energy calculations, we demonstrate that multilayered Janus
graphene oxide nanopores exhibit exceptional and tunable ICR performance
mediated by interlayer coupling. These structures achieve a rectification
ratio enhancement of up to 2 orders of magnitudefrom ∼2
in a single layer to over 2000 at 3.5 V/nm in multilayered configurationsand
a shift of the peak rectification field from 0.7 to 3.5 V/nm with
increasing layer number. Ion distribution analyses reveal distinctive
ionic enrichment-depletion behavior unique to multilayered architectures.
Thermodynamically, we unveil that synergistic interlayer coupling
fundamentally reshapes the free energy landscape, creating a highly
asymmetric profile with multiple energy barriers and wells due to
entropyenthalpy competition. Importantly, entropy is identified
to play a critical role in stabilizing energy wells and facilitating
directional ion transporta mechanism absent in single-layer
systems. These insights provide a mechanistic basis for ion rectification
and establish design principles, such as interlayer spacing or number
control, for developing high-performance ionic membranes and nanofluidic
devices.