Deformation behaviors of hydrogen filled boron nitride and boron nitride - carbon nanotubes: Molecular dynamics simulations of proposed materials for hydrogen storage, gas sensing, and radiation shielding

Boron nitride nanotubes (BNNTs) have been extensively studied for hydrogen storage, sensing, and radiation shielding applications. The deformation behaviors of pristine, defective, and H₂-encapsulated closed-end armchair BNNTs and BNNT-carbon nanotube (CNT) heterostructures are investigated using molecular dynamics employing the ReaxFF interatomic potential and a combination of Tersoff, adaptive intermolecular reactive empirical bond order, and Lennard-Jones potentials. The calculated elastic properties for pristine BNNTs and CNTs are in excellent agreement with published reliable data. The nanotube length and diameter, defects, entrapped hydrogen content, and temperature all affect the mechanical properties significantly. The ReaxFF potential predicts H₂ molecule adsorption on B atoms of undeformed BNNTs whilst under strain, the H₂ molecules show preference for the N atoms. Hydrogen adsorption leads to lowering of the elastic and fracture strength of BNNTs. The ReaxFF potential is shown to be a reliable forcefield for investigating the interaction of H₂ molecules with BNNTs and BNNT-CNT heterotubes.