Comment on Nanoscale Wetting of Crystalline Cellulose

TL;DR

This paper critiques previous MD simulations of cellulose wetting by water, emphasizing that the choice of water model critically affects results, with more realistic models like TIP4P2005 providing different insights than TIP3P.

Contribution

It highlights the importance of selecting appropriate water models in MD simulations of wetting phenomena, demonstrating that TIP4P2005 yields more accurate surface tension results than TIP3P.

Findings

TIP3P underestimates water surface tension

TIP4P2005 accurately reproduces water surface tension

Simulation results vary significantly with water model choice

Abstract

In a recent publication, Trentin et al employed Molecular Dynamics (MD) simulations for the theoretical study of the wetting of the different polymorphs of cellulose by water, using the widely employed TIP3P model of water. Here we show that the selection of the particular water model employed in the simulations has a critical impact in the results, a point overlooked by the authors. In particular, the TIP3P model of water has an unrealistically low value of the surface tension which compromises wetting studies made with this model. Slightly more complex models such as TIP4P2005 correctly reproduce the surface tension of water. As a consequence, the results of MD simulations of cellulose wetting using the low-tension TIP3P model show full wetting in situations that the more realistic TIP4P2005 water model predicted the formation of a water droplet onto cellulose.