The nonlocal dielectric response of water in nanoconfinement

TL;DR

This paper develops a theoretical model to understand the dielectric behavior of water confined in nanogaps, integrating boundary effects and bulk correlations, supported by simulations and experimental data.

Contribution

It introduces a minimal Landau-Ginzburg field-theory model for nanoconfined water's dielectric properties, combining nonlocal bulk effects and surface interactions.

Findings

The model explains low dielectric permittivity in nanoconfined water.

Simulations and experiments validate the theoretical predictions.

Boundary conditions significantly influence dielectric responses.

Abstract

Recent experiments reporting a very low dielectric permittivity for nanoconfined water have renewed the interest to the structure and dielectric properties of water in narrow gaps. Here, we describe such systems with a minimal Landau-Ginzburg field-theory composed of a nonlocal bulk-determined term and a local water-surface interaction term. We show how the interplay between the boundary conditions and intrinsic bulk correlations encodes dielectric properties of confined water. Our theoretical analysis is supported by molecular dynamics simulations and comparison with the experimental data.