Molecular dynamics simulation of wetting and interfacial behaviors of argon fluid confined in smooth and groove-patterned rough nano-channels

Wetting and interfacial behaviors of argon fluid confined in smooth and groove-patterned rough nano-channels are investigated through molecular dynamics (MD) simulation. The results demonstrate that, for smooth channels, lyophilic channels change to lyophobic as energy factors decrease from 1.0 to 0.1 and contact angles exhibit a simple linear dependence on the energy factors. When energy factor is smaller than 0.6, a novel three-phase solid–vapor–liquid interface takes place of solid–liquid interface, and vapor tunnel is discovered. For rough channels, the wetting and interface properties are similar with those of smooth channels. The roughness makes contact angles smaller for lyophilic channels, and larger for lyophobic channels. There are two density layering effects due to the adsorption in nano-grooves. The patterns of fluid contacting with the solid surfaces conform to Wenzel model at larger energy factors, while it agrees with Cassie model at smaller energy factors.