Structural and electronic characteristic dataset of the water on basal surface the cis- and trans-vacant variety of a montmorillonite.

The data given in the paper were obtained using CASTEP based on the density functional theory (DFT) applying a basis set of plane waves and PBE exchange-correlation functional. Van der Waals interactions were considered by the Grimme-D2 semi-empirical correction. The data include the optimized geometry and electronic properties of the equilibrium state of the non-hydrated cis- and trans-vacant variety of a Na-montmorillonite (MMT) and its state after the adsorption of water molecules. The data on hydration shells formed by the Na+ cation on the basal surface of MMT are also presented. The data are presented on the behavior of crystalline hydroxyl groups and water molecules during their adsorption. Data files of the optimized crystal structures and electronic properties can be read by the public text editors.

Atomic-level understanding of interface interactions in a halloysite nanotubes-PLA nanocomposite.

To understand the nature of the bonding mechanism between poly(lactic acid) (PLA) and halloysite nanotubes (HNT), a first-principles DFT study was performed on the adsorption behavior of the PLA monomer, lactic acid (LA), on the outer, inner, and edge surfaces of the HNT. The role of LA functional groups, and its orientation behavior in the formation of bonds with HNT are systematically studied. Analysis of the adsorption energy, total and partial electron density of states (DOS), electric charge transfer between LA atoms and HNT mineral surfaces shows that van der Waals attraction governs their interaction. The calculations of the most stable adsorption configurations of LA show that the predominant number of hydrogen bonds is determined by the activity of the carboxyl functional group of LA on the hydroxylated surfaces of HNT. The important role of the -OH surface groups in the mechanism of lactic acid binding has been established; their absence on the external siloxane surface significantly reduces the LA affinity for HNT. The binding energy of lactic acid on the hydroxylated internal and edge surfaces of the HNT is much higher (by about 275%) than on the external siloxane surface. Mulliken population analysis showed that the formation of a hydrogen bond with the LA atomic groups leads to a more significant redistribution of charge on the inner and edge surfaces of the HNT in comparison with its outer surface. Van der Waals attraction between the LA and HNTs, as well as hydrogen bonds, is responsible for the formation of the bonding mechanism in halloysite nanotubes-PLA nanocomposite. Our results are in accord with available literature.