Electrical insulating MXene/PDMS/BN composite with enhanced thermal conductivity for electromagnetic shielding application

Insulating materials with effective electromagnetic interference (EMI) shielding and heat dissipation are urgently required for modern electronic devices and systems, but it seems that the EMI shielding cannot be compensated without sacrificing the electrical insulation performance. In this study, a layer-by-layer spin coating process has been proposed to prepare multilayer films (MXene/polydimethylsiloxane/boron nitride, MXene/PDMS/BN) with ordered alternate structures, and the EMI shielding effectiveness (EMI SE), thermal conductivity, along with electrical insulation properties of multilayer films have been systematically investigated. The conductive network of MXene/PDMS layer was in-plane constructed, leading to the effective EMI shielding of the multilayer films. Moreover, the BN/PDMS layer can insulate the conductive path through plane and provides effective heat dissipation for multilayer films. The EMI SE of multilayer films is positively related to the number of layers, but the increase in the number of layers will deteriorate the thermal conductivity and electrical insulation performance. The EMI SE of the multilayer film with 11-Layers structure can reach 35.2 dB at 10.9 GHz, with a thermal conductivity of 0.65 W/m·K, and volume resistivity of 2.9 × 1012 Ω cm, as well as a breakdown strength of 3.29 KV/mm, respectively. This research can shed new light on the development of multifunctional composite, which can be envisioned as an advanced electronic packaging material.