Superhydrophobic and thermally conductive carbon black/hexagonal boron nitride@Fe3O4/cellulose composite paper for electromagnetic interference shielding

Herein, a series of superhydrophobic thin polyacrylic resin-coated carbon black (CB)/hexagonal boron nitride (h-BN)@Fe3O4/cellulose composite papers with good flexibility, low density (similar to 0.67 g/cm(3)), high electrical conductivity (similar to 0.065 S/cm), good thermal conductivity (0.462 W.m(-1).K-1), and with water contact angle (WCA) of 153 degrees were successfully fabricated by a facile dip-coating/spraying method. The CB-BN@Fe3O4 distribution in cellulose matrix provided high electrical conductivity in the in-plane and thickness directions. The electrical conductivity in both in-plane and thickness directions increased by increasing the number of vacuum-assisted dip-coating cycles. Moreover, these composites exhibited excellent electromagnetic interference shielding effectiveness (EMI SE) in the frequency range of 8.2-12.4 GHz. The absorption was the main mechanism for attenuation of EM waves for this composite paper. A multilayer of this composite with 12 wt% filler exhibited a higher EMI SE of 68.2 dB compared to its monolayer composite. The composites showed good thermal stability and excellent stability against washing and 150 times bending tests. Overall, this study proposes that polyacrylic resin-coated CB/BN@Fe3O4/cellulose papers can be used as wallpaper in buildings such as hospitals and antenna rooms that are exposed to electromagnetic waves.