Boron nitride nanosheet@penetrating carbon nanotube boosted electromagnetic wave absorption and thermal conduction of polyvinyl alcohol composites

The high integration and miniaturization of modern electronic equipment are limited by thermal radiation and electromagnetic pollution, posing new requirements for both thermal conduction and electromagnetic interference protection. This work fabricated the heterostructure boron nitride nanosheet@carbon nanotube composites (BNNS@CNTs) using a two-step method. The introduction of BNNS reduced the excessive electrical conductivity of CNTs, achieving effective impedance matching. Furthermore, the heterostructures coupling multiple electromagnetic loss mechanisms enhanced the ability to absorb electromagnetic waves. As a result, the composites demonstrated an effective absorption bandwidth (EAB) of 6.83 GHz and a minimum reflection loss (RL_min) of −52.67 dB. Additionally, the construction of an electron-phonon dual thermal conduction carrier and a multi-scale thermal network significantly improved the thermal conduction ability of the matrix. The BNNS@CNTs/PVA composite coating attained a thermal conductivity of 2.051 W/(m·K), which is 12.6 times greater than that of the pure matrix. The exceptional electromagnetic wave absorption and thermal conduction capabilities of these heterostructure composites exhibited great potential for application and were expected to applied for solving thermal management and electromagnetic interference problems of electronic devices.