SiO2 Nanostructure-Based Aerogels with High Strength and Deformability for Thermal Insulation

Conventional SiO2 aerogelscomposed of 0-dimensionalnanoparticles do not have large-scale compression, tensile, and sheardeformation capabilities, and the poor mechanical properties hindertheir further development and application. We report a scalable strategyto construct the nanoporous network of a SiO2 aerogel byalternately linking octa(aminophenyl)-T8-POSS and hexaphthalic acid.The resulting SiO2 aerogel exhibits high strengths (compression,tensile and shear strengths are 26.4, 9.16, and 8.31 MPa, respectively),excellent deformabilities (fracture compression, tensile, and shearstrains are 82.63%, 57.81% and 108.02%, respectively), flexbile processabilityand good structural stability (only 1.7% plastic deformation occursafter 100 load-unload cycles at a large compression strainof 70%). Also, the mesoporous interconnected nanoskeleton with highporosity and the composition of fully hydrophobic groups also givethe aerogel low thermal conductivities (0.02854 W/(m K) at 25 & DEG;Cand 0.04638 W/(m K) at 300 & DEG;C) and superhydrophobic properties(hydrophobic angle 160 & DEG; and saturated mass moisture absorptionrate about 0.375%). The combination of these excellent propertiesensures that the aerogel can be used as an efficient thermal insulationmaterial for extreme environments, such as those where comprehensivemechanical and hydrophobic properties are strictly required.

Automated summary

Conventional SiO2 aerogels made of 0-dimensional nanoparticles lack large-scale deformation capabilities and have poor mechanical properties, limiting their further development and application. In this study, a scalable strategy is proposed to construct a nanoporous network in SiO2 aerogels, which results in high strengths, excellent deformabilities, flexible processability, and good structural stability. The aerogel also exhibits low thermal conductivities and superhydrophobic properties, making it suitable for thermal insulation in extreme environments where comprehensive mechanical and hydrophobic properties are required.