Efficiently Prepared Silicone Aerogels with Tailorable Rigidity-Flexibility and High Thermal Stability via a One-Step Sol–Gel Process of Polymethoxysiloxane

Owing to their unique porous structure and ultralow density, silicone aerogels have emerged as a disruptive solution to extreme environmental challenges and lightweight requirements. However, silicone aerogels suffer from severe structural collapse during fabrication and difficulty in control mechanical properties. To address these challenges, we employed a polymer-based siloxane precursor, polymethoxysiloxane (PMOS), and utilized its distinctive structure to successfully synthesize silicone aerogels with intact internal network architecture via a one-step preparation and APD strategy. Simply by adjusting the precursor concentration, we achieved precise modulation of the pore architecture, facilitating the production of silicone aerogels with adjustable mechanical properties ranging from rigid (PMSQ3) to flexibility (PMSQ12). Moreover, PMSQS, obtained through modification with PMSQ12 and trimethylchlorosilane (TMCS), which demonstrated a specific surface area of 1251 m2/g, and excellent thermal stability, with 482 °C of Td5%, 528 °C of Tmax, 17% of residual mass fraction at 800 °C. Otherwise, PMSQS also exhibited a low thermal conductivity of 0.023 W/(m·K) and complete recovery after 60% compressive strain. In addition, a paramagnetic composite silicone aerogel (PMSQFe) was developed by incorporating fumed silica and nano-Fe3O4 based on PMSQ3, which displayed oil-adsorption capacity with magnetic recyclability. This work establishes PMOS as a cost-effective precursor for efficiently prepared silicone aerogels with adjustable rigidity-flexibility, with applicated in thermal insulation, separation and responsive materials.