Key findings
In bulk form, liquid water has a high dielectric constant (≈ 80 at room temperature) and weak electrical conductivity — traits that support its roles as solvent and medium for biomolecular interactions.
However, when water is confined to nano-scale channels only 1–2 nm thick (roughly 4–5 molecular layers), its behaviour changes dramatically: Its in-plane dielectric constant shoots above 1,000, resembling that of ferroelectric crystals; and its in-plane ionic conductivity increases by several orders of magnitude (up to ~3 S/m) before decreasing at the smallest thicknesses. These effects arise because extreme confinement disrupts the hydrogen-bond network of bulk water, enabling a more collective dipole reorientation and enhanced proton transport.
Why it matters
This change in behavior has broad implications in many fields as stated now in this News and Views Nature article by Domingo and Verdaguer. In biology & biophysics, many essential processes (e.g., ion transport through membrane channels, water layers around proteins and lipid membranes) involve confinement of water at the nanoscale. The observed changes in dielectric screening and proton movement could impact our understanding of those systems.
In atmospheric & earth sciences, water in the upper atmosphere or in nanometre-scale pores of aerosol particles may behave differently than assumed, as it was already observed by A. Verdaguer in another article a few years ago. This could affect models of ice nucleation, cloud formation and climate processes.
Finally, in materials science & nanotechnology, the discovery suggests that liquid water under confinement could be exploited as an active component in nanoscale devices, membranes (e.g., for desalination), fuel cells, batteries and other functional systems.
Role of ICMAB
ICMAB researcher Albert Verdaguer (SURFACES group) is a co-author of this work, reflecting ICMAB’s engagement at the forefront of nanoscience and interfacial phenomena, specially related to water. This study aligns strongly with ICMAB’s mission to explore material behaviour at the nano- and interfaces scale, and to translate fundamental insights into technological and environmental applications.
Outlook and future directions
This work re-defines how we think about water: under extreme confinement it ceases to be a passive solvent and instead becomes an electrically active medium with properties akin to engineered materials. However, while the results are striking, many questions still remain open. This opens exciting new pathways in both fundamental science and applied research, from biomolecular interfaces to next-generation nanoscale devices, to try to answer them.
Reference Articles
Extreme confinement unleashes water’s hidden electrical capabilities
Neus Domingo & Albert Verdaguer
News and Views, Nature, 15 October 2025
DOI: 10.1038/d41586-025-03128-y
Pores dominate ice nucleation on Feldspars
E. Pach and A. Verdaguer*
The Journal of Physical Chemistry C 2019, 123, 20998
DOI: 10.1021/acs.jpcc.9b05845
Investigating the Ubiquitous Presence of Nanometric Water Films on Surfaces
S. Santos*, C.A. Amadei, L. Chia-Yun, T. Olukan, J.-Y. Lu, J. Font, V. Bracons, A. Verdaguer*, M. Chiesa*
The Journal of Physical Chemistry C 2021, 123, 20998. Journal Cover
DOI: 10.1021/acs.jpcc.1c03767Journal Cover: ICMAB - New Cover in The Journal of Physical Chemistry C on how water nanofilms affect solid-medium interactions
