Tunable Stress‐Responsive Biomimetic Multi‐Stage Porous Aerogels as Advanced Wideband Acoustic Absorbers with Superior Flame Resistance

Abstract Multi‐stage porous aerogels have spurred relentless innovation and surpassed traditional boundaries by redefining the landscape of advanced sound management technologies. Harnessing stress‐responsive tuning properties in aerogels intricately enhances acoustic attenuation. Multi‐stage porosity provides enhanced efficiency across a variety of acoustic environments. In addition to facilitating acoustic attenuation, aerogels demonstrating exceptional flame resistance represent an innovative solution specifically engineered for high‐temperature applications. In this study, a biomimetic multi‐stage porous aerogel, BMPA, is developed created through mild microbial fermentation, resulting in a distinctive internal structure. BMPA enabled the tuning of porosity as high as 93%, with a resulting ultralight density of 0.0518 g cm − 3 . The uncompressed BMPA material reduced sound levels at 1.5 kHz and, when stretched, further improved attenuation for 2, 2.5, and 3 kHz. Its multistage pore structure lowered noise from 85.7 to 68.7 dB, achieving a total reduction of 17 dB—an impressive advancement in sound management! BMPA treated with inorganic zinc solutions demonstrates significant flame resistance, achieving a V‐0 rating and a limiting oxygen index value exceeding 60%. The groundbreaking development of multi‐stage porous aerogels significantly enhances the potential for next‐generation materials that excel in flame resistance and noise absorption.