DFT study of non-covalent interaction mechanisms of solvents with GO surfaces and the solvent-mediated GO interaction

摘要

Understanding the non-covalent interaction between solvent and graphene oxide (GO) is of significance to the application of GOs. Herein, the adsorption interactions of several typical solvents with GO surfaces were studied by density functional theory, in which non(less)-polar, protic polar, and aprotic polar solvents were included. The interaction energies, geometrical characteristics, and bonding natures have been characterized. The atomsin-molecule theory and the natural orbitals for chemical valence analysis reveal that miscellaneous non-covalent interaction mechanisms appear between solvent molecules and GO surfaces, covering a change from vdW (pi-pi) interaction for non(less)-polar solvents to moderate and strong hydrogen bonding interactions for polar solvents. There exists an approximately linear correlation between the interaction energies and the interfacial electron density topological parameters. The orbital interaction mechanisms and charge transfer performances have also been disclosed. We further attempt to establish a correlation between the GO-GO interaction free energies in solvents and the solvent-GO interactions, which illustrates that increasing the solvent-GO interaction can weaken the aggregative degree of GOs in the solvent media. Our simulation results not only are valuable to the solventphase processing of GOs, but also provide new binding mechanisms on GO surfaces, which lays a foundation on the functional modification of GO nanomaterials.