Volume 56

Study on the Regulation of Nanostructure on Wettability of CO2 Droplets on Substrate Molecular Dynamics Simulation Hengguang Cao, Xuewen Cao, Jiang Bian

Abstract

This study employs molecular dynamics simulations to investigate how nanostructures influence the wetting behavior of CO2 droplets by varying the solid–liquid interaction coefficient (α), surface feature size, and surface configuration. The results reveal that increasing α drives the transition of droplets from the Cassie state to the Wenzel state. Under identical α, the contact angle on square pillar surfaces is larger than on smooth surfaces. Notably, at α = 0.14, introducing a pillar structure can switch the surface from CO2-philic to CO2-phobic. Further modifications in pillar height and solid fraction induce a Wenzel-to-Cassie transition, significantly increasing the contact angle and reducing CO2–surface interaction energy. Surfaces featuring square pillars, cylinders, or grooves exhibit similar effects in tuning droplet wetting. These insights provide valuable guidelines for optimizing materials and surface designs to enhance CO2 condensation and liquefaction efficiency.

Keywords Carbon dioxide, nanostructure, wettability, contact angle, wetting state