Superelastic Fire‐Safe Aerogel with Hierarchical Structures via Dual Templates Aided by Microbubble Engineering
Xiaoyang Yu, Huan Li, Ning Kang, Shouxiang Lu, Mingjun Xu, Man Pun Wan
Abstract
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.