Aerogels are renowned for their ultralow density and superior thermal insulation. However, the poor adhesion of traditional aerogels, arising from their porous surfaces and rigid frameworks, presents a significant challenge for integration into functional systems. Inspired by the core-shell architecture of expanded thermoplastic polyurethane (ETPU) beads, which feature a thermoplastic shell enabling thermally activated adhesion and a resilient core ensuring mechanical recovery, we developed self-assembled adhesive aerogel capsules (SAACs). SAACs emulate this decoupling strategy with a porous chitosan/silica aerogel (CTS/SA) core preserving the thermal insulation, while an adhesive chitosan/carboxylated nitrile rubber (CTS/XNBR) shell enables adhesion. Through electrostatically-based self-assembly and freeze-drying, negatively charged XNBR encapsulates a positively charged CTS/SA scaffold, forming a core-shell structure. SAACs can be thermally processed at mild temperatures (≤ 80°C) to adhere into 3D assemblies, conform to irregular shapes, and adhere to diverse substrates. Despite their adhesive capability, SAACs retain low density, low thermal conductivity (30-39 mW·m-1·K-1), and inherent flame retardancy. Unlike conventional aerogels or ETPU, SAACs combine the thermal processability of elastomers with the insulation and fire resistance of aerogels, offering a promising platform for applications in on-site thermal management, energy conservation, and fire protection.
Li et al. (Mon,) studied this question.