Insights on the Role of Many-Body Polarization Effects in the Wetting of Graphitic Surfaces by Water
RP Misra and D Blankschtein, JOURNAL OF PHYSICAL CHEMISTRY C, 121, 28166-28179 (2017).
It is well-known that atoms in a substrate placed in contact with a polar solvent like water experience a finite electric field from the solvent molecules. Nevertheless, the effect of this electric field on the wetting properties of the substrate remains unknown. In this study, by carrying out molecular dynamics (MD) simulations with force field parameters derived from ab initio simulations, we develop a theoretical framework to quantify the role of the polarization of graphene in the wetting of graphitic surfaces by water. Our study shows that a self- consistent modeling of the polarization of graphene yields a water contact angle on graphite that is remarkably different from the contact angle that results if the polarization energy is instead modeled implicitly using a Lennard-Jones potential, a typical approximation used in all previous MD simulation studies on the wetting of graphitic surfaces. Our findings reveal that polarization has a more pronounced effect on the interfacial entropy of water compared to dispersion interaction. Consequently, polarization and dispersion interactions contribute differently to the wetting of graphitic surfaces. Our study significantly advances our understanding of the watergraphene interface, which is important for practical applications of graphene-based nanomaterials in osmotic power harvesting and seawater desalination.
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