Stiff–Soft Synergistic Assembly of Mechanically Adaptive Silica Aerogel Composites
Silica aerogels are recognized as leading super-insulating materials due to their ultralow thermal conductivity, yet their intrinsic brittleness and poor processability restrict practical deployment in complex industrial and extreme environments. This study introduces a macro-scale 'stiff–soft' synergistic strategy, combining a macroscopically processable, soft-and-tough framework as the load-bearing component with hard-and-brittle polymethylsilsesquioxane (PMSQ) aerogels as the insulating component. A pressure-driven assembly process enables viscosity-tunable PMSQ gel inks to be controllably infused into various hollow frameworks, including honeycomb panels, wheat straws, and hollow fibers. Guided by a modified Hagen–Poiseuille model, ink viscosity is precisely matched to the geometric parameters of the hollow structures. The resulting composites achieve compressive strength of 2.5 MPa, flexural strength of 6.25 MPa, and tensile strength of 40 MPa, while maintaining excellent thermal insulation. This versatile and scalable approach offers a new design paradigm for mechanically adaptive silica aerogel composites in thermal management applications.