Aerogels, shaped as fibers, films, as well as monoliths, have demonstrated a plethora of applications in both academia and industry due to charming properties including ultralow density, large specific surface area, high porosity, etc., however studies on more complicated aerogel forms (e.g., honeycombs) with more powerful applications have not been fully explored. Herein, the Kevlar aerogel honeycomb is firstly constructed through a dry ice-assisted 3D printing method, where the Kevlar nanofiber ink is printed directly in dry ice freezing atmosphere, followed by supercritical fluid drying. The subsequent 3D Kevlar/shear-stiffening gel (SSG) honeycomb (3D-KSH) can be obtained by selective nanoconfining of SSG into nanopores of the aerogel skeleton wall (with the loading amount of 93 wt%) rather than into open honeycomb channels, solving the leakage, creep deformation, and shape design infeasibility of the SSG. Combining the advantages of Kevlar, honeycomb and SSG, the fabricated 3D-KSH shows obvious smart responsive behavior to external stimulus. Additionally, the 3D-KSH has high strain rate sensitivity (sensitivity factor of 4.16 × 10⁻⁴) and excellent impact protection performance (energy absorption value up to 176 J g⁻¹ at the strain rate of 6300 s⁻¹), which will significantly broaden application prospect in some intelligent protection fields.

中文翻译：

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具有选择性纳米限制剪切硬化凝胶的智能吸能气凝胶基蜂窝

由于具有超低密度、大比表面积、高孔隙率等迷人特性，气凝胶具有纤维状、薄膜状和单块状等多种形状，在学术界和工业界都有广泛的应用，但是对更复杂的气凝胶形式的研究（例如，蜂窝）具有更强大的应用程序尚未得到充分探索。在此，Kevlar 气凝胶蜂窝首先通过干冰辅助 3D 打印方法构建，其中 Kevlar 纳米纤维墨水直接在干冰冷冻气氛中打印，然后进行超临界流体干燥。随后的 3D Kevlar/剪切硬化凝胶 (SSG) 蜂窝 (3D-KSH) 可以通过将 SSG 选择性纳米限制在气凝胶骨架壁的纳米孔中（负载量为 93 wt%）而不是进入开放的蜂窝通道，解决了SSG的渗漏、蠕变、外形设计不可行等问题。结合 Kevlar、蜂窝和 SSG 的优点，制造的 3D-KSH 对外部刺激表现出明显的智能响应行为。此外，3D-KSH 具有高应变率灵敏度（灵敏度因子为 4.16 × 10^{−4 )和优异的冲击防护性能（6300 s −1}应变速率下能量吸收值高达176 J g ⁻¹），将显着拓宽在一些智能防护领域的应用前景。