Hydrophobic and flame-retardant multifunctional foam for enhanced thermal insulation and broadband microwave absorption via a triple-continuous network of RGO/MWCNT-melamine composite.

Multifunctionalization is the future development trend for electromagnetic wave absorption (EMA) materials to satisfy practical scenarios. In this manuscript, a lightweight RGO/MWCNT modified melamine sponge (CGMFs) with a 3D porous triple-continuous network is developed, which exhibit much enhanced microwave absorption performance and multifunctional characteristics. The micro/nano-structure and EMA performance of CGMFs can be effectively controlled by adjusting the concentration and proportion of RGO and MWCNT. It is found that excellent impedance matching property from the 3D porous structure and strong electromagnetic wave (EMW) dissipation property of RGO and MWCNT network can synergistically enhanced the broadband EMA performance. The CGMFs present remarkable effective absorption bandwidth (EAB, reflection loss value ≤ −10 dB) of 10.8 GHz and extremely high reflection loss value of −50.43 dB at a thickness of 4.6 mm. Moreover, the CGMFs exhibit good mechanical stability, which can be compressed, bent, and twisted arbitrarily. Benefiting from enhanced hydrophobicity, heat insulation, and nonflammability, the CGMFs also exbibit attractive functions of self-cleaning, thermal insulation, infrared stealth, and flame retardancy. This study paves the way for scalable fabrication of next-generation multifunctional high-performance broadband EMA materials for practical application. [Display omitted] • Lightweight RGO/MWCNT modified melamine sponge (CGMFs) with a 3D porous triple-continuous network is developed. • The CGMFs present remarkable effective absorption bandwidth of 10.8 GHz and high reflection loss value of −50.43 dB. • The CGMFs present good multifunction of self-cleaning, thermal insulation, infrared stealth, and flame retardancy. [ABSTRACT FROM AUTHOR]