Confined water in the low hydration regime

TL;DR

This study uses molecular dynamics to explore how water behaves when confined in silica pores at low hydration levels, revealing layering effects, hydrogen bond distortions, and a transition in water molecule dynamics near surfaces.

Contribution

It provides new insights into the microscopic behavior of confined water in silica pores, especially regarding hydrogen bonding and dynamic regimes at low hydration levels.

Findings

Strong layering effects due to hydrophilic silica surface

Distortion of hydrogen bond network in confined water

Transition from Brownian to non-Brownian motion near the surface

Abstract

Molecular dynamics results on water confined in a silica pore in the low hydration regime are presented. Strong layering effects are found due to the hydrophilic character of the substrate. The local properties of water are studied as function of both temperature and hydration level. The interaction of the thin films of water with the silica atoms induces a strong distortion of the hydrogen bond network. The residence time of the water molecules is dependent on the distance from the surface. Its behavior shows a transition from a brownian to a non-brownian regime approaching the substrate in agreement with results found in studies of water at contact with globular proteins.