Elucidating slipping behaviors between carbon nanotubes: Using nitrogen doping and electron irradiation to suppress slippage

The slipping phenomenon of carbon nanotubes (CNTs) and nitrogen-doped CNTs (NCNTs) compromises their mechanical strength and potential applications. Elucidation of this microscopic phenomenon is essential for applying CNTs as high-strength materials. This study investigates the slip mechanisms in CNTs and NCNTs, with the aim of enhancing their mechanical properties. By combining various analytical techniques, we elucidated the adhesion and slipping behaviors of CNT bundles under various conditions. van der Waals forces were found to dominate the stick–slip phenomenon in stable CNT stacks. The introduction of amorphous carbon and subsequent electron irradiation led to the formation of stronger covalent bonds between the tubes, enhancing the mechanical resilience. Notably, NCNTs exhibited a higher frequency of covalent bond excitation by electron irradiation than CNTs. These findings indicate the crucial role of electron irradiation in strengthening the covalent bonds within CNT and NCNT bundles, marking a significant contribution to the mechanical applications of nanotechnology.