Dynamically Slow Processes in Supercooled Water Confined Between Hydrophobic Plates

TL;DR

This study investigates how water confined between hydrophobic plates exhibits different dynamic behaviors at various pressures and temperatures, revealing complex hydrogen bond network formations and their effects on water's mobility and dehydration.

Contribution

It provides a detailed analysis of the pressure-dependent dynamical regimes of confined water and links hydrogen bond dynamics to observed behaviors.

Findings

High pressure inhibits hydrogen bond network formation, leading to rapid dehydration.

Lower pressure causes heterogeneities and non-exponential correlation functions.

Very low pressure results in dynamical arrest due to hydrogen bond network formation.

Abstract

We study the dynamics of water confined between hydrophobic flat surfaces at low temperature. At different pressures, we observe different behaviors that we understand in terms of the hydrogen bonds dynamics. At high pressure, the formation of the open structure of the hydrogen bond network is inhibited and the surfaces can be rapidly dehydrated by decreasing the temperature. At lower pressure the rapid ordering of the hydrogen bonds generates heterogeneities that are responsible for strong non-exponential behavior of the correlation function, but with no strong increase of the correlation time. At very low pressures, the gradual formation of the hydrogen bond network is responsible for the large increase of the correlation time and, eventually, the dynamical arrest of the system and of the dehydration process.