Nacre-Mimetic Nanocomposite Aerogels with Exceptional Mechanical Performance for Thermal Superinsulation at Extreme Conditions,Advanced Materials

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Nacre-Mimetic Nanocomposite Aerogels with Exceptional Mechanical Performance for Thermal Superinsulation at Extreme Conditions
Advanced Materials ( IF 27.4 ) Pub Date : 2023-04-20 , DOI: 10.1002/adma.202300813
Junyan Zhang ₁ , Junjie Zheng ₁ , Mengyue Gao ₁ , Chengjian Xu ₁ , Yanhua Cheng ₁ , Meifang Zhu ₁

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Thermal protection under extreme conditions requires materials with excellent thermal insulation properties and exceptional mechanical properties to withstand a variety of complex external stresses. Mesoporous silica aerogels are the most widely used insulation materials due to their ultralow thermal conductivity. However, they still suffer from mechanical fragility and structural instability in practical applications. Herein, a nacre-mimetic nanocomposite aerogel, synthesized via in situ growth of inorganic minerals in a lamellar cellulose nanofibrous network, is reported. The multiscale structural adaptation of the inorganic–organic components endows nanocomposite aerogels with rapid configuration recovery during ambient pressure drying. The resulting aerogels show ultralow thermal conductivities (17.4 mW m⁻¹ K⁻¹ at 1.0 atm). These aerogels also integrate challenging mechanical properties, including high compressive stiffness to resist deformation under the pressure of an adult, superelasticity to prevent static and dynamic stress cracking even under the crushing of a vehicle (1.6 t), and high bending flexibility to adapt to any surface. Moreover, they exhibit excellent structural stability under fatigue stress/strain cycles over a wide temperature range (−196 to 200 °C). The combination of high thermal insulation performance and excellent mechanical properties offers a potential material system for robust thermal superinsulation under extreme conditions, especially for aerospace applications.

中文翻译：

仿珍珠质纳米复合气凝胶具有卓越的机械性能，可在极端条件下实现绝热

极端条件下的热防护需要材料具有优异的隔热性能和卓越的机械性能，以承受各种复杂的外部应力。介孔二氧化硅气凝胶由于其超低的导热系数而成为应用最广泛的隔热材料。然而，它们在实际应用中仍然存在机械脆弱性和结构不稳定的问题。本文报道了一种仿珍珠质纳米复合气凝胶，是通过层状纤维素纳米纤维网络中无机矿物的原位生长合成的。无机-有机成分的多尺度结构适应性赋予纳米复合气凝胶在常压干燥过程中快速构型恢复。所得气凝胶表现出超低导热率（1.0 atm 下为 17.4 mW m ^-1 K ^-1）。这些气凝胶还集成了具有挑战性的机械性能，包括在成人压力下抵抗变形的高压缩刚度、即使在车辆（1.6 吨）挤压下也能防止静态和动态应力开裂的超弹性，以及适应任何环境的高弯曲灵活性。表面。此外，它们在较宽的温度范围（-196 至 200 °C）的疲劳应力/应变循环下表现出优异的结构稳定性。高隔热性能和优异的机械性能的结合提供了一种潜在的材料系统，可在极端条件下实现坚固的超隔热，特别是对于航空航天应用。

更新日期：2023-04-20

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