Hybrid Amyloid–Boron Nitride Aerogels for Lightweight Sound Insulation

Boron nitride (BN) is a lightweight, thermally stable, and chemically inert material widely used in electronics and insulation, yet its synthesis typically relies on energy-intensive, high-temperature routes. Here, we introduce a sustainable, bottom-up strategy to fabricate hybrid boron nitride-amyloid fibril (BNAF) aerogels, in which whey protein amyloid fibrils serve as renewable scaffolds that assist the organization of BN-rich domains. A mild ultrasonication-freeze-drying process yields ultralight aerogels with hierarchical porosity, increased BN-like ordering relative to the protein-free control, and fibril-induced reinforcement. The hybrid aerogels combine mechanical reinforcement, thermal stability under moderate-use conditions, and strong acoustic performance, achieving sound absorption coefficients above 0.8, noise reduction coefficients up to 0.63, and sound transmission losses of 25-30 dB. This combination of low density and strong sound shielding compares favorably with common lightweight acoustic materials such as fiberglass, establishing amyloid-assisted BN-protein hybrid aerogels as promising candidates for moderate-temperature, weight-sensitive noise-reduction applications.