Role of cationic organisation on water dynamics in saponite clays

29 March 2023, Version 1
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

Water dynamics impacts many phenomena from geosciences to biology, especiallly in confined environments. In the presence of charged interfaces, there are some ions the role of which with regards to the water dynamics is unclear. Here a synthetic saponite clay, which is oriented in a film, is used as confining medium in the bilayer state. It confines two water layers between negatively charged planes, the charge of which is compensated by sodium cations. Water dynamics is determined both parallel and perpendicular to the charged clay layers with Neutron Spin Echo (NSE). This technique gives access to long enough times and directly provides the intermediate scattering function that is calculated on the other hand by Molecular Dynamics (MD) simulations. These latter also enable the study of cations dynamics, not experimentally accessible on this time scale. The results point towards a huge role of these cations on the water dynamics, mainly through their local structure and localization between the charged confining planes.

Keywords

water dynamics
clays
confined water
neutron spin echo
molecular dynamics

Supplementary materials

Title
Description
Actions
Title
Supplementary information
Description
Figures not shown in the main text, for the interested reader. Methodology for the calculation of MSD of water molecules inside and outside cation hydration spheres.
Actions

Comments

Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.