Research On The Mechanical Properties And Heat Conduction Properties Of Single-walled Carbon Nanotube Junctions Formed By Nanobuds

Carbon nanotubes(CNTs) and their junctions are the basic units of the carbon nanotube network structure. It is of great significance for futural practical application that nanotube can be connected by CNT junctions or cross linking agents, which is not only used to get CNT bulk material, but also is the promising building blocks for CNT nanoelectronic devices. The techniques that have been proposed to form CNT junctions include electron beam irradiation or ion irradiation, mechanical manipulation with atomic force microscope(AFM), chemical functionalization, heat welding and so on. However these methods are imperfect. It is an important issue to find more effective methods to form the CNT junctions.In this paper, a novel method in which C-C bonded junction of SWCNT can be formed by means of welding via nanonbuds is proposed, and the mechanical and thermal properties of heat welded nanobuds junctions are investigated. Major contents are summarized below:(1) Two methods for the formation of CNT nanonuds are studied, and a novel method are proposed to form the CNT junctions via heat welding of nanobuds at experimentally-relevant temperatures. The most important advantage of the proposed method is the needed heat welding temperature is independence of the diameter of the tube. It provides a simple and feasible way to form a continuously interconnected CNTs network. The mechnical stability of the CNTs and CNTs bundle nanobud junctions are analyzed using the calculations based on MD simulations.(2) A novel method to produce a single carbon chain bridging the outer wall of two SWNTs through separating the nanobud junctions is presented. Results show that the obtained long single carbon atom chain(SCC) has good thermal stability up to a temperature of 2000 K. The laddering effect, in which the atom chain can be continuously pulled out from the fullerene molecule in the nanobuds junction under tensile loading, and extraordinary room temperature superplasticity are exhibited in this section.(3) NEMD simulations and applying heat method are employed to study the intra-tube junction thermal resistance and inter-tube junction thermal conductance of the contancting nanobud, and are compared with previous work on X-junction.