“…To narrow the gap further, the structural parameters such as length, diameter and alignment of CNTs should be better controlled. For strength improvement, the intertube load transfer may be manipulated by already reported methods such as electron irradiation 31,32 , chemical treatment 33 and polymer impregnation [34][35][36] , forming primary bonds between CNTs, which are much stronger than Van der Waals interactions. For conductivity improvement, tube chirality should be particularly tailored 37 , and iodine doping 13,38 and metal coating 39,40 may be imposed.…”