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.