Near-zero Temperature Coefficient of Resistance for a Single-Walled Carbon Nanotube Polymer Nanocomposite

Temperature dependence of electrical resistance of single-walled carbon nanotube (SWCNTs)/epoxy nanocomposites, which is characterized by a temperature coefficient of resistance (TCR), is experimentally investigated. In the existing literature, there are biased TCR values with non-monotonic temperature dependence, including both negative and positive values. In this study, we demonstrate that the influence of environment temperature can be greatly minimized by ensuring the CNT/epoxy nanocomposite is fully cured along with controlling CNT concentration and selecting an appropriate polymer matrix. In addition, agglomeration of CNTs significantly influences the performance of CNT/polymer nanocomposites. Resistance values remained nearly constant at a CNT concentration of approximately 1 wt.% below the glass transition temperature. It is also observed that in a fully cured CNT/epoxy nanocomposite with the microscale conductive pathway as the main conductance mechanism, the coefficient of thermal expansion (CTE) of the matrix is a critical characteristic, resulting in a consistent increasing trend in TCR.