Revealing the effective electrical and thermal conductivity of MXene/polymer nanocomposites: A unified micromechanics‐based theoretical analysis

Abstract In contrast to the extensive research on traditional CNT‐based nanocomposite, the exceptional functional behaviors of novel MXene/polymer nanocomposite remain to be explored. In particular, both the interface effects and microstructural characteristics serve as the crucial factors in determining overall electrical and thermal behaviors. In this research, a unified micromechanics‐based homogenization model is formulated for predicting effective electrical and thermal conductivity of MXene/polymer nanocomposites. A multi‐scale homogenization scheme based on the effective‐medium approximation is established to connect the microstructural characteristics and overall functional behaviors. The functional interface effects between the MXene and polymer matrix, including the tunneling effect and Kapitza effect, are responsible for the excellent electric and thermal properties of overall nanocomposites. The tunneling effect is illustrated by the Simmon's tunneling function based on the filler‐dependent tunneling distance, while the Kapitza effect is interpreted by the resistance function at the MXene‐polymer interface. A bottom‐to‐up computational procedure from the nano scale to macro scale is adopted under a hierarchical geometrical setting. The predicted electrical and thermal conductivity of MXene/polymer nanocomposites are calibrated by the experiment over a wide range of MXene volume fractions. An obvious percolated phenomenon is unraveled for the functional behaviors of MXene/polymer nanocomposites. The effective electrical and thermal conductivity are revealed to increase significantly after reaching the percolation threshold. A high MXene aspect ratio possesses positive impacts on functional behaviors of MXene/polymer nanocomposites. This paper can provide the instructions for the microstructural optimization on electrical and thermal conductivity of MXene/polymer nanocomposites. Highlights A unified homogenization model is developed for MXene‐based nanocomposites. The functionalized tunneling and Kapitza effects are considered at the interface. A bottom‐to‐up computational procedure is adopted under hierarchical setting. Both the predicted electrical and thermal conductivity agree with the experiment. An obvious percolative behavior is observed for MXene‐based nanocomposites.