Molecular dynamic insight into aluminum nanoparticles self-encapsulated by CNTs and their oxygen ignition

Metal nanoparticles tend to deactivate due to spontaneous migration-aggregation and continuous surface oxidation. Nanocapsules provide a brand-new strategy to tackle these challenges. In this work, two types of nanocapsules were designed and applied to active aluminum. The self-assembly details between carbon nanotubes (CNTs) and aluminum nanoparticles (ANPs) are elucidated through molecular dynamics methods. The stability and controllability of capsules I-VI consisting of various lengths of CNTs were revealed by means of reactive molecular dynamics simulations. The results indicate that the driving force for the self-assembly of nanocapsules is the vdW interaction. The assembled capsule has excellent stability, and the interaction energy between the tube and ANPs and between the tubes is as high as −599.55 and −1,014.78 kcal/mol, respectively. The opening of the nanocapsules during combustion is dependent on the length of the CNTs and temperature. Above 2000 K, the outer CNT can be opened when the length is greater than 31.73 Å. When used as propellants, pyrotechnics and explosives, these nanocapsules can be triggered remotely by visible/infrared lasers without the need of detonating wires.