Investigation of the wettability of chemically heterogeneous smooth and rough surfaces using molecular dynamics simulation

Development of a transferable coarse-grained model of polydimethylsiloxane

“…Given the importance of water–PDMS interaction in microfluidics systems, several data can be found in literature regarding the contact angle of water on PDMS. Experimental 41–45 and computational 46,47 studies give values in the range of 100–115° for water–PDMS contact angle. He et al 45 report a contact angle of 90° ± 5° for acetonitrile, a conventional solvent for DNA synthesis.…”

Correlation between Contact Angle and Water Film Energetics in Carbon Dioxide–Water–Clay Mineral Interfacial Systems: A Molecular Dynamics Study

“…This approach would be a valuable tool for unraveling complex CO 2 –water–rock systems in the reservoir and caprock where multiple influencing factors, such as ion concentration, ion species, pH, and the types of mineral surfaces (e.g., differences between basal and edge planes), are interrelated. Moreover, this method could be particularly beneficial for the evaluation of wettability not only on flat surfaces or slit-pore systems but also on rough and heterogeneous surfaces, − in which case the interfacial profile would not be symmetric or easily fitted and converted to the macroscopic contact angle. Therefore, we postulate that the present PMF profiles obtained using MD simulations will inspire further atomic-scale studies on the wettability of rock surfaces.…”

“…According to the free energy variation determined for a representative CO 2 molecule permeating the water film, the amount of work needed for this molecule to approach the surface increases with increasing negative layer charge. On the basis of these findings, we proposed a novel approach to complement direct contact angle calculations by means of computing the permeation free energy. This method offers a promising approach to investigating the wetting phenomena even on rough surfaces or complex systems, − in which the interfacial profile may not be easily converted to the macroscopic contact angle. Furthermore, the present analysis of the structure and dynamics of the adsorbed water provides us with new insights into the change in the film energetics from an atomic-scale viewpoint, which cannot be gained using the widely used thermodynamic model, namely, the Frumkin–Derjaguin equation. − ,, Therefore, our approach demonstrated in this study would be a valuable framework aimed at enhancing the comprehension of the variation of the water contact angle on hydrophilic mineral surfaces. …”

“…On the basis of these findings, we proposed a novel approach to complement direct contact angle calculations by means of computing the permeation free energy. This method offers a promising approach to investigating the wetting phenomena even on rough surfaces or complex systems, − in which the interfacial profile may not be easily converted to the macroscopic contact angle.…”

Molecular dynamics simulation of the surface wettability of typical minerals in shale

“…The Smart method (Li et al, 2021) was used for structural optimization, the truncation radius was set at 1.25 nm (Jin et al, 2022), the wettability model was the COMPASS force field (Sun, 1998), and the time step was 1 fs. The system was simulated in a canonical ensemble (NVT) (Boudaghi & Foroutan, 2022) at 5000 ps to ensure the accuracy of the simulation. The velocity Verlet algorithm was used to solve Newton's equations of motion.…”