Enhanced dispersion and interfacial bonding in CNT/Cu composites via carbonized polymer dot surface engineering of CNT to achieve superior mechanical and electrical properties

Abstract

In the field of energy and electricity, there is an urgent demand for Cu matrix composites with excellent electrical conductivity and mechanical properties. Therefore, in this work, one-step hydrothermal approach was applied to in-situ generate carbonized polymer dot (CPD) for surface modification of carbon nanotube (CNT) without affecting their intrinsic structure. By taking advantage of synergistic effect of CPD@CNT, high electrical conductivity and high strength are obviously produced. This is related to the numerous oxygen-containing functional groups on CPD surface, which contribute notable dispersibility. And during the sintering process, owing to variations in thermal stability, some of these functional groups are thermally decomposed to generate O atoms and it rapidly diffuse into the surrounding Cu atoms to form Cu₂O. Additionally, some of CPD structures are thermally decomposed, resulting in the formation of amorphous C, which bonds tightly with the matrix Cu. Consequently, through the “bridging” effect of CPD, the load and electron transfer are improved, and the reinforcing effect of CNT in Cu matrix composites is fully realized. As a result, the 0.3 wt% CPD@CNT/Cu composites possess a high electrical conductivity of 96 %IACS and a remarkable super strength of 341.36 MPa. This study presents an effective strategy for the design of advanced copper matrix composites.