Analysis of individual molecular dynamics snapshots simulating wetting of surfaces using spheroidal geometric constructions
School of Engineering
Accurate characterization of wettability of minerals is important for efficient oil recovery and carbon geosequestration. In studies where molecular dynamics simulations are used to compute the contact angle, emphasis is often placed on results or theoretical details of the simulations themselves, overlooking potentially applicable methodologies for determination of the contact angle. In this manuscript, a concept of a method utilizing spheroidal geometric constructions to estimate the contact angle of a water droplet on a silica surface in carbon dioxide atmosphere is outlined and applied to the final snapshots of two molecular dynamics simulation runs. Two carbon dioxide pressures and two wettability modes (hydrophilic and hydrophobic) are examined to assess the method’s performance. The most stable 6-membered ellipselike rings (001) pristine surface of alpha-quartz is reconstructed using molecular dynamics and its wettability is then investigated for the first time. The outcomes of the calculations are compared with results produced with the isodensity chart method, and good agreement with the latter approach is demonstrated. The proposed method can be used as an alternative, or in conjunction with other techniques, to increase the confidence in contact angle estimations via molecular mechanics calculations. Reliable contact angle estimations, on the other hand, can guarantee accurate storage capacity and security of carbon capture and storage projects.