Pressure-Volume Response in Nanomaterials: Contrasting Graphenic Sheets, Oxide Ceramics, and Transition Metal Architectures

This investigation presents a comprehensive theoretical examination of pressure-induced volumetric compression characteristics in five structurally diverse nanomaterials: graphite, aluminium oxide (Al2O3), single-walled carbon nanotubes (SWCNTs), nano-epsilon-phase iron (nano-ε-Fe), and nano-nickel (nano-Ni), representing carbon allotropes, ceramic oxides, and transition metal systems. Four established equations of state (Tait, Murnaghan, Kholiya and Chandra, and Shanker) were employed using experimentally derived bulk modulus values and their pressure derivatives from literature to model relative volumetric changes under applied pressure up to 16 GPa. The analysis reveals material-specific compressibility behaviours dictated by bonding characteristics, atomic configuration, and dimensionality. Al2O3 demonstrates the highest incompressibility among studied materials due to its strong ionic-covalent bonding, while SWCNTs exhibit pronounced nonlinear compression attributed to structural instabilities under confinement. Nano-Ni and nano-ε-Fe show intermediate compressibility with enhanced sensitivity due to nanoscale effects including surface energy influences and modified coordination environments. The study validates the applicability of classical equations of state for predicting nanoscale mechanical responses and provides critical insights for material selection in nanodevice design for biomedical, energy, and high-pressure applications.