Energetics, Interlayer Molecular Structures, and Hydration Mechanisms of Dimethyl Sulfoxide (DMSO)-Kaolinite Nanoclay Guest-Host Interactions

Two dimensional (2D) kaolinite nanoclay is an important natural mineral with promising application potential, especially tuned with organic intercalates. However, thus far, the organics-kaolinite guest-host interactions, the atomic scale structures of organic intercalates under confinement, and molecular level mechanisms of hydration are rarely systematically explored using both experimental and computational methodologies. We integrated density functional theory with dispersion scheme (DFT-D) with various experimental methods to investigate the intercalation of dimethyl sulfoxide (DMSO) in kaolinite with and without hydration. The kinetic, thermodynamic, and structural impacts of hydration were highlighted. In short, water molecules significantly promote intercalation of DMSO into kaolinite because of favorable intercalation energy, which is enabled by effective hydrogen bonding at the guest species (DMSO and water)-kaolinite interfaces.

Automated summary

This study integrated density functional theory with dispersion scheme (DFT-D) and various experimental methods to investigate the intercalation of dimethyl sulfoxide (DMSO) in kaolinite with and without hydration. It highlighted the kinetic, thermodynamic, and structural impacts of hydration, showing that water molecules significantly promote intercalation of DMSO into kaolinite due to favorable intercalation energy enabled by effective hydrogen bonding.