Highly conductive carbon nanotubes-boron nitride-thermoplastic polyurethane composite thin films with ultra broadband and efficient electromagnetic interference shielding up to 110 GHz and heat dissipation abilities

The miniaturization and integration of electronic devices have led to an increased accumulation of heat, which can disrupt normal functioning. Their functionalities are also severely affected when they are exposed to the abundant electromagnetic interference (EMI) resulting from the rapid development of fifth-generation telecommunication technology extended to mmWaves and sixth-generation telecommunication frequencies up to 110 GHz. Therefore, it is urgent to develop composite materials with excellent EMI shielding effectiveness and heat dissipation abilities. Herein, we have fabricated an all-in-one thin film composite using carbon nanotubes (CNT), boron nitride (BN), and thermoplastic polyurethane (TPU) through a layer-by-layer casting method to create a composite supported by hydrogen bonding with impressive EMI shielding and heat dissipation properties. The high electrical conductivity of the CNT-BN-TPU composite resulted in the highest EMI shielding effectiveness, ranging from 90.66 dB in Ka-band to 79.8 dB in W-band, at a thickness of 100 μm, with absorption efficiency of 83.07% at 34 GHz and 80.85% at 100 GHz, respectively. The composite demonstrated excellent heat dissipation, thanks to its outstanding out-of-plane thermal conductivity, which reached 1.971 W/mK. We believe that our proposed method for producing an all-in-one composite thin film with excellent EMI shielding and thermal management capabilities could be a useful approach for the next generation of smart electronic devices.