AUTHOR=Yong Wei , Wei Zhi-jie , Liu Yu-yang , Wang De-qiang , Cui Yong-zheng 

TITLE=A molecular dynamics investigation on CO2–H2O–CH4 surface tension and CO2–CH4–H2O–graphite sheet contact angles

JOURNAL=Frontiers in Energy Research

VOLUME=11

YEAR=2023

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2023.1271359

DOI=10.3389/fenrg.2023.1271359

ISSN=2296-598X

ABSTRACT=<p><bold>Introduction:</bold> We perform molecular dynamics (MD) simulations of nanoscopic liquid water drops on a graphite substrate mimicking the carbon-rich pore surface in the presence of CH<sub>4</sub>/CO<sub>2</sub> mixtures at temperatures in the range 300 K–473 K.</p><p><bold>Methods:</bold> The surface tension in MD simulation is calculated via virial expression, and the water droplet contact angle is obtained through a cylindric binning procedure.</p><p><bold>Results:</bold> Our results for the interfacial tension between water and methane as a function of pressure and for the interfacial tension between water and CH<sub>4</sub>/CO<sub>2</sub> mixtures as a function of their composition agree well with the experimental and computational literature.</p><p><bold>Discussion:</bold> The modified Young’s equation has been proven to bridge the macroscopic contact angle and microscopic contact with the experimental literature. The water droplet on both the artificially textured surface and randomly generated surface exhibits a transition between the Wenzel and Cassie–Baxter states with increased roughness height, indicating that surface roughness enhances the hydrophobicity of the solid surface.</p>