Effects of acid treatments on physical properties of CNT wires for wiring applications

Carbon nanotube (CNT) wires are mechanically stronger and extremely lightweight nanomaterials with highly efficient mechanical, thermal and electrical properties compared to the conventional materials. The new applications of these superior nanomaterials include aircraft, energy, biomedical, sensor, defense, electronics and space. One very interesting potential application of carbon nanotubes is in electrical wiring. Conventional electrical wires made of copper and aluminum suffer from several problems including weight (an issue in aerospace applications), skin effect (hindering their use in modern telecommunications), mechanical performance (critical in overhead power lines and ductility), and electromigration (severely damaging microscopic wires in electronics applications). Moreover, the growing demand for these conventional metal conductors and the continually increasing prices suggests that a low-cost material that can outperform conventional conductors would be highly desirable. Hence, carbon nanotubes are the material of great interest for those. In the study, CNT wires were immersed into the acid bath under ambient conditions for different time periods to analyze their physical property changes. Chemical treatment drastically changed the physical dimensions of the CNT wire, including increase in diameter and a decrease in length. Also, chemical bonds were created between the CNTs, which might increase the properties of the CNT wires. Under tensile load, chemical treatment has been proven to slightly increase the tensile strength and conductivity of the CNT wires, but the test results were scattered substantially. This study may create new possibilities to enhance the physical and chemical properties of CNT wires in a number of different industrial applications.