The percolation transition of hydration water: from planar hydrophilic surfaces to proteins

TL;DR

This paper investigates the percolation transition of hydration water forming a hydrogen-bonded network across different systems, revealing a universal 2D percolation behavior and a method to estimate the threshold via hydrogen bonds.

Contribution

It demonstrates that hydration water undergoes a 2D percolation transition on various surfaces, providing a practical way to estimate the percolation threshold using hydrogen bond calculations.

Findings

Hydration water forms a 2D percolation network on different surfaces.

The percolation threshold correlates with an average of 2.0 to 2.3 hydrogen bonds.

Calculation of hydrogen bonds enables estimation of percolation thresholds.

Abstract

The formation of a spanning hydrogen-bonded network of hydration water is found to occur via a 2D percolation transition in various systems: smooth hydrophilic surfaces, the surface of a single protein molecule, protein powder and diluted peptide solution. The average number of water-water hydrogen bonds nH at the percolation threshold varies from 2.0 to 2.3, depending on temperature, system size and surface properties. Calculation of nH allows an easy estimation of the percolation threshold of hydration water in various systems, including biomolecules.