Clay mineral materials have attracted attention due to their many properties and applications. The applications of clay minerals are closely linked to their structure and composition. In this paper, we studied the electronic structure properties of kaolinite, muscovite, and montmorillonite crystals, which are classified as clay minerals, by using DFT-based ab initio packages VASP and the OLCAO. The aim of this work is to have a deep understanding of clay mineral materials, including electronic structure, bond strength, mechanical properties, and optical properties. It is worth mentioning that understanding these properties may help continually result in new and innovative clay products in several applications, such as in pharmaceutical applications using kaolinite for their potential in cancer treatment, muscovite used as insulators in electrical appliances, and engineering applications that use montmorillonite as a sealant. In addition, our results show that the role played by hydrogen bonds in O-H bonds has an impact on the hydration in these crystals. Based on calculated total bond order density, it is concluded that kaolinite is slightly more cohesive than montmorillonite, which is consistent with the calculated mechanical properties.

Montmorillonite clay (MMT) has been widely used in engineering and environmental applications as a landfill barrier and toxic waste repository due to its unique property as an expandable clay mineral that can absorb water easily. This absorption process rendered MMT to be highly exothermic due to electrostatic interactions among molecules and hydrogen bonds between surface atoms. A detailed study of a large supercell model of structural clay enables us to predict long-term nuclear waste storage. Herein, a large solvent MMT model with 4071 atoms is studied using ab initio density functional theory. The DFT calculation and analysis clarify the important issues, such as bond strength, solvation effect, elasticity, and seismic wave velocities. These results are compared to our previous study on crystalline MMT (dry). The solvated MMT has reduced shear modulus (G), bulk modulus (K), and Young’s modulus (E). We observe that the conduction band (CB) in the density of states (DOS) of solvated MMT model has a single, conspicuous peak at −8.5 eV. Moreover, the atom-resolved partial density of states (PDOS) summarizes the roles played by each atom in the DOS. These findings illuminate numerous potential sophisticated applications of MMT clay.

This study presents a rapid and eco-friendly strategy for synthesizing zinc (Zn²⁺) complexes using polyphenol-rich black tea extract (BTS) as a natural chelating agent and their incorporation into polyvinyl alcohol (PVA) to develop tunable optical composite films. FESEM analysis reveals that the incorporation of Zn–metal complexes disrupt the fibrillar morphology of semi-crystalline PVA, indicating significant microstructural modification. FTIR results confirm the coordination interaction between Zn²⁺ ions and polyphenol ligands, as well as strong interfacial bonding within the polymer matrix. The introduction of these green-synthesized complexes leads to a pronounced enhancement in optical properties, with the optical absorption edge decreasing from 6.24 eV to 1.21 eV. This behavior is associated with the formation of localized electronic states and increased charge carrier density, as supported by refractive index and dielectric analyses. Optical parameters, including oscillator and dispersion energies, were evaluated using the Wemple–DiDomenico model, while band-gap characteristics were determined using Tauc analysis. Overall, this work demonstrates a sustainable coordination-driven approach for engineering polymer composites with tunable optical properties, offering strong potential for photonic and optoelectronic applications.