Ultraviolet-assisted direct-write printing strategy towards polyorganosiloxane-based aerogels with freeform geometry and outstanding thermal insulation performance

Developing aerogels with a tailored geometric feature is of prime importance for enlarging their functional effects in application scenarios. However, conventional manufacturing techniques have remained challenging in the on-demand shaping of aerogels due to their costly and time-consuming fabrication process and poor designability of casting molds. Herein, an ultraviolet-assisted direct-write printing strategy has been proposed for fabricating polyorganosiloxane-based aerogels with tunable molecular triple-crosslinks consisting of hydrogen bonds, hydrocarbon chains, and polysiloxanes. The implementation of direct-write printing depends on the close synergy of consecutive ink deposition and instantaneous photopolymerization, appearing as a considerable characteristic of solidification-while-printing, which is conducive to constructing spatially freeform geometries with high structural complexity and shape fidelity. The resultant 3D-printed polyorganosiloxane-based aerogels exhibit outstanding nanoporous performances, such as low density (0.14 g·cm−3), high surface area (484 m2·g−1), superhydrophobicity (water contact angle, 150°), high specific modulus (27.9 kN·m·kg−1), and low thermal conductivity (37.48 mW·m−1·K−1), which are ideal materials for shape-dominated thermal insulation applications. This work would provide an alternative printing strategy to fabricate nanoporous materials with arbitrary architectures for wider applications.