Multiscale Design of Dual-Gradient Metamaterials Using Gel-Mediated 3D-Printed Graphene Aerogels for Broadband...

Area of Science:

• Materials Science
• Nanotechnology
• Electromagnetics

Background:

• 3D-printed graphene aerogels show promise for electromagnetic wave absorption (EWA) due to low density and tunable properties.
• High conductivity in graphene aerogels often leads to impedance mismatch, limiting their EWA performance.
• 3D printing constraints affect the dielectric properties of graphene inks, hindering the development of high-performance absorbers.

Purpose of the Study:

• To develop a polyacrylic acid (PAA) gel-mediated strategy for multiscale regulation of 3D porous graphene oxide (GO) aerogels.
• To improve the rheological and dielectric properties of GO/PAA composites for direct ink writing (DIW) and enhanced EWA.
• To create lightweight, broadband EWA materials by optimizing the composition-structure-performance relationship.

Main Methods:

• Utilized a PAA gel-mediated approach to control the rheology and dielectric loss of GO/PAA composites.
• Employed thermal reduction to decompose PAA into amorphous carbon nanoparticles on reduced graphene oxide (rGO), enhancing interfacial polarization and conductive loss.
• Integrated DIW with the developed aerogel to fabricate a metamaterial absorber (MA) with dual gradients.

Main Results:

• Achieved a significant reduction in aerogel density from 28.2 to 6.9 mg cm⁻³.
• The optimized rGO/PAA aerogel demonstrated a minimum reflection loss (RL) of -39.86 dB and an effective absorption bandwidth (EAB) of 8.36 GHz.
• The designed MA exhibited an ultrawide EAB of 14 GHz over a total thickness of 7.8 mm.

Conclusions:

• The PAA gel strategy effectively tunes rheology and dielectric properties for DIW and EWA.
• The resulting rGO/PAA aerogels offer superior impedance matching and synergistic loss mechanisms for enhanced absorption.
• This work presents a viable coupled design paradigm for engineerable, lightweight, broadband EWA materials.