A Self-Catalyzed, Seed-Regulated Nucleation-Growth Strategy for Ambient-Pressure-Dried Transparent Aerogels Combining Mechanical Robustness and Thermal Insulation

Although transparent insulating aerogels are promising for energy-efficient glazing, their practical application remains limited by optical scattering, structural inhomogeneity, poor mechanical properties, and complex preparation processes. Herein, we report an octa(tetramethylammonium) polyhedral oligomeric silsesquioxane (OctaTMA-POSS)-regulated nucleation-growth strategy to fabricate mechanically robust transparent aerogels via ambient-pressure drying. Methyltriethoxysilane (MTES) was used as the precursor, and OctaTMA-POSS served as a multifunctional nanobuilding block whose intrinsic alkaline catalytic activity eliminated the need for additional acid or base catalysts. The rigid POSS cage acted as a seed-like nucleation center and was incorporated into the aerogel skeleton to regulate primary-particle growth and reinforce the framework. In situ monitoring of the gelation process revealed that this strategy effectively regulated primary-particle growth, yielding a fine, uniform nanoporous skeleton. The resulting aerogel exhibited a visible-light transmittance of up to 88.86%, a low thermal conductivity of 23.1 mW·m-1·K-1, a maximum deformation of 63.7% with a compressive strength of 12.12 MPa, and an initial decomposition temperature (Td5) of 520 °C. This work provides a simple and cost-effective route to high-performance transparent insulating aerogels for energy-efficient glazing and building-envelope applications.