Thermal conductivities of Ti3C2Tx MXenes and their interfacial thermal performance in MXene/epoxy composites - a molecular dynamics simulation

Ti-based MXene has been widely investigated for its excellent electronic properties but the thermal performance of Ti3C2Tx still remains uncharted on the molecular scale, which could significantly affect the thermal conductivity of their composites. This work adopted molecular dynamics method and effective medium theory (EMT) to analyze the thermal conductivity of 4 types of MXenes, including Ti3C2, Ti3C2F2, Ti3C2O2 and Ti3C2(OH)(2), as well as their epoxy composites. The results showed that the terminal groups could reduce the phonon scattering in MXenes which could increase the thermal conductivity and also the interfacial affinity between MXene and epoxy molecules by improving interfacial binding energy. The Ti3C2O2 has the highest thermal conductivity of 140.25 Wm(-1)K(-1), while Ti3C2(OH)(2 )has the lowest interfacial thermal resistance, which could lead a higher thermal conductivity in composite when its flake was under the critical size. The EMT results showed that Ti3C2O2 could significantly improve the TC of epoxy under a lower filler content; and the MD simulation parameters were validated by the comparison between other works and EMT prediction in this work. The current study provides suggestions for selecting Ti3C2Tx as fillers in composites that need fast heat dissipation. (C) 2022 Elsevier Ltd. All rights reserved.