Aerogels have attracted extensive attention due to their remarkable properties, such as lightweight and low thermal conductivity. However, it remains challenging to simultaneously achieve high temperature insulation (>1000 °C) and improve mechanical performance. Herein, we report a cactus-inspired spiral structure preparation strategy via freezing-assisted direct ink writing (DIW). By synergistically controlling the rotation angle (θ) and printing spacing (x), we fabricate SiO₂/ZrO₂ aerogels with programmable macroscopic spiral architectures. The SiO₂/ZrO₂ aerogels with θ = 40° and x = 1.3 mm exhibit excellent thermal insulation (30.2 mW·m⁻¹·K⁻¹). However, the compressive strength is only 159.3 kPa at 24.2% fracture strain. To enhance the mechanical performance without compromising thermal insulation, an arctangent-topological DIW strategy is proposed, which employs the arctangent function αₙ = arctan(1/n) to fabricate aerogels with four-fold rotational symmetry. When αₙ = 26.6° (n = 2), the SiO₂/ZrO₂ aerogels exhibit a favorable thermal insulation performance (33.9 mW·m⁻¹·K⁻¹) while achieving a significant enhancement in compressive strength (341.7 kPa at 24.6% fracture strain). Application of SiO₂/ZrO₂ aerogels for thermal insulation of electronic chips and flame nozzles are demonstrated. The results demonstrate the feasibility of the SiO₂/ZrO₂ aerogels for high temperature applications. This study offers a strategy for developing of high-temperature aerogels with combined good thermal insulation and mechanical properties.
Li et al. (Sun,) studied this question.