Functional dopamine-Zn-MOF crosslinked gelatin composite aerogels with hierarchical structures for enhanced thermal insulation and flame retardancy

Biopolymer aerogels have shown broad prospects in efficient thermal management. However, their inherent flammability imposes limitations on practical utilization. In this study, a gelatin-based composite aerogel (Zn-MOF-DA/GA) was successfully prepared by dopamine-modified Zn-MOF nano-reinforcement and multiple crosslinking in gelatin solution. The Zn-MOF-DA component not only facilitated the uniform dispersion of MOF nanoparticles but also enhanced interfacial molecular interactions through multifunctional groups and intrinsic physical properties. The as-prepared aerogel with a hierarchical porous structure, low bulk density, and high mechanical strength exhibits excellent thermal insulation performance (33.02–37.62 mW·m⁻ 1 ·K⁻ 1 ) and anisotropic thermal properties. Moreover, the nano-porous Zn-MOF-DA significantly improved the flame retardancy of composite aerogel, reducing the peak heat release rate and total smoke release by 48% and 96%, respectively, compared to gelatin aerogel. The design strategy of multi-crosslinking and nano-reinforcement provides a broad prospect for sustainable aerogels in the field of thermal management and fire safety. Graphical abstract