Enhanced Thermal Transport in Aramid Composite Films via Intrinsic Interfacial Interaction and Synergistic Orientation

The heat dissipation of high-power chips places higher demands on the thermal conductivity (<i>λ</i>) of polymer-based thermal interface materials (TIMs) to ensure the stable operation of the chips. However, the interfacial thermal resistance (ITR) greatly restricts further improvement. Herein, 1D multiwalled carbon nanotubes modified with carboxyl (CNTs-_COOH) were introduced to the aramid matrix via blade coating, and a strategy of the intrinsic interfacial interaction and synergistic orientation was ingeniously adopted to enhance thermal transport. Results indicate that the strong hydrogen bonding, π-π interactions between CNTs-_COOH and aramid, and the in-plane consistent orientation of the CNTs-_COOH play a synergistic strengthening role in the interface and bulk thermal transport. The in-plane <i>λ</i> (<i>λ</i>_<i>∥</i>) of the obtained aramid composite with 40 wt % CNTs-_COOH (ACNTs-_COOH-40%) reaches 12.6 W/mK, about 420% higher than that of pure aramid. The range of variation of <i>α</i>_<i>∥</i> with temperature is approximately within 0.8 mm²/s, demonstrating excellent thermally conductive stability. The phonon transmission spectra and ITR of CNTs-_COOH/aramid, CNTs/aramid, and CNTs/EVA were calculated through theoretical simulation, further verifying the effectiveness of enhancing heat transport through strong interfacial interaction. The strategy of intrinsic interfacial interaction and synergistic orientation has promoted the development of TIMs, providing an effective measure for the heat dissipation of high-power electronic devices.