# Thermodynamics of Molecular Transport Through a Nanochannel: Evidence of Energy–Entropy Compensation

## TL;DR

This paper explores how molecules move through a nanochannel, showing that energy and entropy balance each other depending on how strongly the molecules interact.

## Contribution

The study reveals a linear energy–entropy compensation mechanism in molecular transport across different interaction strengths.

## Key findings

- Weak interactions favor even molecule distribution due to entropy dominance.
- Strong interactions favor localized configurations due to energetic dominance.
- Intermediate interactions lead to oscillatory behavior due to energy–entropy compensation.

## Abstract

In this work, the thermodynamics of molecular transport between two compartments connected by a nanochannel is investigated through an analysis of internal energy and entropy changes, with a focus on how these changes depend on intermolecular interaction strength. When interactions are weak, resembling gas-like behavior, entropy dominates and favors configurations in which molecules are evenly distributed between the two compartments, despite an increase in internal energy. In contrast, strong interactions, characteristic of liquid-like behavior, lead to dominant energetic contributions that favor configurations with molecules localized in a single compartment, despite entropy loss. Intermediate interaction strengths yield comparable entropic and energetic contributions that cancel each other out, resulting in oscillatory behavior between evenly distributed and localized configurations, as observed in previous work. This thermodynamic analysis reveals energy–entropy compensation, in which entropic and energetic contributions offset each other across different interaction strengths; notably, this compensatory relationship exhibits a linear trend. These findings provide insight into the thermodynamic origins of molecular transport behavior and highlight fundamental parallels between molecular transport and molecular binding, the latter being particularly relevant to molecular recognition and drug design.