Interfacial Electric Fields in Water Nanodroplets Are Weakly Dependent on Curvature and pH.
7 affiliations
- 1Department of Chemical, Biological, Pharmaceutical, and Environmental Sciences, University of Messina, Viale F. Stagno d'Alcontres 31, Messina98166, Italy.
- 2Institute for Chemical-Physical Processes, National Research Council (CNR-IPCF), V.le F. Stagno d'Alcontres 37, Messina98158, Italy.
- 3Laboratoire de Physique de L'école normale supérieure de Paris, CNRS, École Normale Supérieure Université Paris Sciences et Lettres, Sorbonne Université, Université de Paris, Paris75005, France.
- 4Center for Combustion Energy, Department of Energy and Power Engineering, and Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Tsinghua University, Beijing100084, China.
- 5Ministry of Education Key Laboratory of Cluster Science, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing100081P. R. China.
- 6International Centre for Theoretical Physics (ICTP) , Strada Costiera 11, Trieste34151, Italy.
- 7Institut Universitaire de France (IUF), https://www.iufrance.fr/.
Abstract
The origin of enhanced reactivity in aqueous microdroplets remains unresolved, with interfacial electric fields (IEFs) frequently proposed as catalytic drivers. Here, we present a quantum-mechanical, spatially resolved characterization of the electric field at air-water interfaces by combining deep learning molecular dynamics with ab initio re-sampling. Across planar interfaces and nanodroplets spanning a range of curvatures and charge states, we consistently identify an outward-directed field of ∼1.0-1.2 V/Å along the intrinsic surface normal. Notably, the field magnitude scales linearly with the average number of hydrogen bonds per interfacial molecule, directly linking the IEF to the local hydrogen-bond network. Strikingly, curvature and pH exert only a moderate influence on the IEF, with differences becoming negligible at experimentally relevant droplet sizes and pH regimes. Accordingly, the reactivity enhancements observed in μm-sized droplets cannot be attributed to variations in the IEF, which changes by only ∼10-5 between 3 and 40 μm-sized droplets. Furthermore, the IEF is highly localized within the interfacial region, decaying over just a few Å. This pronounced spatial confinement ties the field to the local electronic structure, establishing the IEF as an intrinsic interfacial property rather than an independent mechanistic driver of "on-water" catalysis.
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BibTeX
@article{amante2026interfacial,
title = {{Interfacial Electric Fields in Water Nanodroplets Are Weakly Dependent on Curvature and pH.}},
author = {Gabriele Amante and Fortunata Panzera and Pengchao Zhang and Gabriele Centi and Jing Xie and Ali Hassanali and A Marco Saitta and Giuseppe Cassone},
journal = {Journal of the American Chemical Society},
year = {2026},
month = oct,
doi = {10.1021/jacs.6c09391},
eprint = {2604.14784},
archivePrefix = {arXiv},
url = {https://europepmc.org/article/MED/42912326},
note = {CC BY},
}
RIS
TY - JOUR
TI - Interfacial Electric Fields in Water Nanodroplets Are Weakly Dependent on Curvature and pH.
AU - Gabriele Amante
AU - Fortunata Panzera
AU - Pengchao Zhang
AU - Gabriele Centi
AU - Jing Xie
AU - Ali Hassanali
AU - A Marco Saitta
AU - Giuseppe Cassone
PY - 2026
DA - 2026/10/01
JO - Journal of the American Chemical Society
DO - 10.1021/jacs.6c09391
UR - https://europepmc.org/article/MED/42912326
AB - The origin of enhanced reactivity in aqueous microdroplets remains unresolved, with interfacial electric fields (IEFs) frequently proposed as catalytic drivers. Here, we present a quantum-mechanical, spatially resolved characterization of the electric field at air-water interfaces by combining deep learning molecular dynamics with ab initio re-sampling. Across planar interfaces and nanodroplets spanning a range of curvatures and charge states, we consistently identify an outward-directed field of ∼1.0-1.2 V/Å along the intrinsic surface normal. Notably, the field magnitude scales linearly with the average number of hydrogen bonds per interfacial molecule, directly linking the IEF to the local hydrogen-bond network. Strikingly, curvature and pH exert only a moderate influence on the IEF, with differences becoming negligible at experimentally relevant droplet sizes and pH regimes. Accordingly, the reactivity enhancements observed in μm-sized droplets cannot be attributed to variations in the IEF, which changes by only ∼10-5 between 3 and 40 μm-sized droplets. Furthermore, the IEF is highly localized within the interfacial region, decaying over just a few Å. This pronounced spatial confinement ties the field to the local electronic structure, establishing the IEF as an intrinsic interfacial property rather than an independent mechanistic driver of "on-water" catalysis.
SN - 0002-7863
SN - 1520-5126
ER -