Quantifying hydrogen bonding using electrically tunable nanoconfined water

TL;DR

This paper presents a new method to quantify hydrogen bonds in water by modeling them as elastic dipoles influenced by electric fields, enabling direct measurement of bond strength and related properties.

Contribution

It introduces a novel elastic dipole model for hydrogen bonds and demonstrates its application in quantifying bond strength using spectroscopic data in water systems.

Findings

Hydrogen bond strength can be directly quantified from spectroscopic measurements.

The model accurately predicts properties like bond length and dipole moment.

Hydrogen bond heterostructures are tunable materials with potential technological applications.

Abstract

Hydrogen bonding plays a crucial role in biology and technology, yet it remains poorly understood and quantified despite its fundamental importance. Traditional models, which describe hydrogen bonds as electrostatic interactions between electropositive hydrogen and electronegative acceptors, fail to quantitatively capture bond strength, directionality, or cooperativity, and cannot predict the properties of complex hydrogen-bonded materials. Here, we introduce a novel approach that conceptualizes the effect of hydrogen bonds as elastic dipoles in an electric field, which captures a wide range of hydrogen bonding phenomena in various water systems. Using gypsum, a hydrogen bond heterostructure with two-dimensional structural crystalline water, we calibrate the hydrogen bond strength through an externally applied electric field. We show that our approach quantifies the strength of hydrogen bonds directly from spectroscopic measurements and reproduces a wide range of key properties of confined water reported in the literature. Using only the stretching vibration frequency of confined water, we can predict hydrogen bond strength, local electric field, O-H bond length, and dipole moment. Our work also introduces hydrogen bond heterostructures - a new class of electrically and chemically tunable materials that offer stronger, more directional bonding compared to van der Waals heterostructures, with potential applications in areas such as catalysis, separation, and energy storage.