Superelastic Fire-Safe Aerogel with Hierarchical Structures via Dual Templates Aided by Microbubble Engineering.

Superelastic aerogels with ultralow thermal conductivity have essential advantages for advanced thermal management systems in energy-efficient buildings. However, inorganic aerogels suffer from brittleness and poor processability, whereas their organic counterparts experience high production costs and inadequate elastic recovery. This study used a dual-template (ice and bubble) strategy to fabricate ultralight, superelastic aerogels with hierarchical porosity inspired by stress-dissipating dome architectures. Microbubbles are engineered via a modified "Tessari method" to create macropores (≈100 µm) while ice-templating introduced aligned pores of a few µm in size during freeze-drying. The synergistic interplay of a rigid gelatine (Ge) skeleton, flexible polyvinyl alcohol (PVA) nodes, and potassium salt-enhanced crystalline domains yielded aerogels with exceptional elasticity, ultralow density and thermal conductivity. Flame retardancy is achieved through potassium salt-mediated catalytic carbonization, reducing the peak heat release rate by 54% and enabling self-extinguishing behavior. Microbubble introduction in precursors can provide macropores for aerogels, which dispersed internal stress during the deformation of aerogel, whereas dynamic hydrogen bonds enabled rapid water-assisted self-healing ability and closed-loop recyclability. Scalable production using commercial compressed air foaming systems and a low raw material cost further highlight its industrial viability. Combined with biodegradability and superior thermal insulation, this work advances sustainable, fire-safe aerogels for multifunctional applications.