Construction of a partially rGO multifunctional aerogel with multi-stage pores for hydrophobicity, thermal insulation and efficient microwave absorption property

Abstract

Microwave absorption materials are urgently demanded in complex electromagnetic (EM) environments. Nevertheless, it remains a considerable challenge to effectively integrate multiple functions into a single material. The porous structural engineering strategy injects infinite vitality into the flexible control and manipulation of their electromagnetic properties, which could simultaneously resist aerodynamic heating and achieve EM stealth. Inspired by this, a superelastic and ultralight partially reduced graphene oxide aerogel (PrGA) with a multi-stage pore structure was fabricated by tailoring the bubble templates and subsequent thermal reduction processes. Importantly, varying the further reduction time of PrGA could regulate the structural regularity, pore sizes and oxygen-containing groups, which in turn affect the polarization loss and conductive loss. Notably, PrGA-4 exhibits remarkable microwave absorption properties, with a minimum reflection loss (RL_min) of −67.89 dB and an expanded effective absorption bandwidth (EAB) of 7.72 GHz at 3.62 mm, covering the entire Ku band. Besides, the RL_min peaks of PrGA display a tendency toward higher frequencies with the increase in further reduction time, which can be attributed to the synergy effect of the unique multi-stage pores structure and enhanced intrinsic conductive network. More importantly, PrGA combines outstanding mechanical properties, hydrophobicity, thermal insulation, and piezoresistive sensing, making it applicable to various and complex application scenarios. This work offers an effective strategy for designing multifunctional and highly efficient microwave absorption materials.