Vertical 3D printing of rGO/CNTs arrays for thermal interface materials with in-situ local temperature monitoring function

The dramatical increase in the integration-level, multifunctionalization and power density of electronic and energy devices has put forward growing demands for heat dissipation and localized temperature monitoring to maintain device performance and lifetime. However, traditional TIMs are always confined to thermal conduction and lack the ability to monitor local temperature anomalies in heat-generating devices. Herein, we demonstrate a flexible TIM capable of localized temperature anomaly monitoring constructed based on vertical three-dimensional (3D) printing of reduced graphene oxide/carbon nanotube (rGO/CNT) arrays with vertically aligned structures on multiple scales. The vertically aligned microstructure enables the rGO/CNTs pillar an outstanding thermal conductivity, up to 38.91 W·m−1 K−1, and the through-plane thermal conductivity of the flexible TIM based on such rGO/CNT vertical arrays also reaches 6.04 W·m−1 K−1. Taking advantage of the independent rGO/CNTs pillar in vertical arrays and the significant difference in thermal conductivity between the rGO/CNT pillars and polydimethylsiloxane (PDMS) matrix, we prepare flexible TIMs capable of in-situ monitoring of local temperature anomalies. This vertical 3D printing of vertically aligned carbon nanomaterials array in multi-scale can be expanded to other nanomaterials in constructing multifunctional TIMs for a range of energy and electronic components, such as power battery packs, CPU, power or communication ICs.