Enhancing thermal safety of hydrophobic silica aerogels by incorporating sodium dodecyl sulfate intercalated layered double hydroxides

To enhance the thermal safety and preserve the excellent thermal insulation of hydrophobic silica aerogels (SA), sodium dodecyl sulfate (SDS) intercalated layered double hydroxides (LDH) was incorporated into SA by in situ doping to form SDS-LDH/SA composites. The intercalation modification by SDS extends the layer spacing of LDH and improves the dispersibility of LDH in SA, in favor of the combination between LDH and SA. The physical combination between the SA and SDS-LDH is demonstrated by FTIR analyses. As the content of SDS-LDH rises, the SDS-LDH/SA continues to exhibit a low density (0.11–0.20 g/cm 3 ), low thermal conductivity (<26.8 mW/m/K), and large specific surface area (709.4–839.2 m 2 /g), ensuring excellent thermal insulation performance. It further finds that the SDS-LDH effectively absorbs heat and inhibits the thermal decomposition of SA. Therein, the onset temperature of thermal decomposition of the SA with 20% SDS-LDH is 114.0 °C higher than that of pure SA. Additionally, it also finds that the gross calorific values of the SDS-LDH/SA decrease with the SDS-LDH content, and all these gross calorific values are lower than that of the pure SA. Hence, SDS intercalated LDH presents significant effects on enhancing the thermal safety of hydrophobic SA without impairing the thermal insulation too much. Graphical Abstract