Designing Stable Graphitic Networks on Ultra-Porous Polyimide Aerogels via Solvent-Guided Structuring

Lightweight, highly porous polyimide (PI) aerogels have emerged as promising candidates for advanced electronic applications due to their exceptional thermal stability, mechanical performance, structural integrity, and low dielectric loss. However, the controlled laser-induced graphitization (LIG) of such ultra-porous polymeric networks remains a critical challenge, as localized high temperatures often trigger polymer backbone degradation and framework collapse. Herein, a chemically engineered PI aerogel via a molecular design strategy that tailors solvent-polymer interactions during gelation to produce a hierarchically porous yet thermally robust network is reported. This substrate preserves its porosity and integrity during high-intensity LIG, enabling the formation of a uniform graphene-carbon conductive phase embedded within the polyimide matrix. The resulting material achieves sheet resistivity as low as 6.5 Ωsq^-1, while retaining excellent dielectric properties (ɛ_r = 1-2, tan δ <0.2) and thermal insulation (30-35 mW m^{- 1} K^{- 1} post-300 °C treatment). This synergy between molecular design, thermal response, and electronic functionality enables integration into multifunctional devices, such as flexible pressure sensors, thermal management layers, and ultralight antennas, demonstrated by a reflection coefficient of -14 dB at 5.4 GHz and a peak gain of 3.9 dBi.