Dielectric Properties of Water in Charged Nanopores

Thomas R. Underwood, Ian C. Bourg

Research output: Contribution to journalArticlepeer-review

Abstract

In this study, we examine the spectral dielectric properties of liquid water in charged nanopores over a wide range of frequencies (0.3 GHz to 30 THz) and pore widths (0.3 to 5 nm). This has been achieved using classical molecular dynamics simulations of hydrated Na-smectite, the prototypical swelling clay mineral. We observe a drastic (20-fold) and anisotropic decrease in the static relative permittivity of the system as the pore width decreases. This large decrement in static permittivity reflects a strong attenuation of the main Debye relaxation mode of liquid water. Remarkably, this strong attenuation entails very little change in the time scale of the collective relaxation. Our results indicate that water confined in charged nanopores is a distinct solvent with a much weaker collective nature than bulk liquid water, in agreement with recent observations of water in uncharged nanopores. Finally, we observe remarkable agreement between the dielectric properties of the simulated clay system against a compiled set of soil samples at various volumetric water contents. This implies that saturation may not be the sole property dictating the dielectric properties of soil samples, rather that the pore-size distribution of fully saturated nanopores may also play a critically important role.

Original languageEnglish (US)
Pages (from-to)2688-2698
Number of pages11
JournalJournal of Physical Chemistry B
Volume126
Issue number14
DOIs
StatePublished - Apr 14 2022

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

Fingerprint

Dive into the research topics of 'Dielectric Properties of Water in Charged Nanopores'. Together they form a unique fingerprint.

Cite this