Li Shu-Liang, Wang Juan, Zhao Hai-Bo, Cheng Jin-Bo, Zhang Ai-Ning, Wang Ting, Cao Min, Fu Teng, Wang Yu-Zhong
The Collaborative Innovation Center for Eco-Friendly and Fire-Safety Polymeric Materials (MoE), National Engineering Laboratory of Eco-Friendly Polymeric Materials (Sichuan), State Key Laboratory of Polymer Materials Engineering, College of Chemistry, Sichuan University, Chengdu 610064, China.
ACS Appl Mater Interfaces. 2021 Dec 15;13(49):59231-59242. doi: 10.1021/acsami.1c17216. Epub 2021 Dec 1.
Biomass aerogels are highly attractive candidates in various applications due to their intrinsic merits of high strength, high porosity, biodegradability, and renewability. However, under low-temperature harsh conditions, biomass aerogels suffer from weakened mechanical properties, become extremely brittle, and lose functionality. Herein, we report a multifunctional biomass aerogel with lamella nanostructures (∼1 μm) fabricated from cellulose nanofibers (∼200 nm) and gelatin, showing outstanding elasticity from room temperature to ultralow temperatures (repeatedly bent, twisted, or compressed in liquid nitrogen). The resultant aerogel exhibits excellent organic solvent absorption, thermal infrared stealth, and thermal insulation performance in both normal and extreme environments. Even at dry ice temperature (-78 °C), the aerogel can selectively and repeatedly absorb organic solvents in the same way as room temperature with high capacities (90-177 g/g). Excellent heat insulation and infrared stealth performances are achieved in a wide temperature range of -196 to 80 °C. Further, this aerogel combines with the advantages of ultralow density (∼6 mg/cm), biodegradability, flame retardancy, and performance stability, making it a perfect candidate for multifunctional applications under harsh conditions. This work greatly broadens application temperature windows of biomass aerogels and sheds light on the development of mechanically robust biomass aerogels for various applications under extreme conditions.
生物质气凝胶因其高强度、高孔隙率、生物可降解性和可再生性等固有优点，在各种应用中是极具吸引力的候选材料。然而，在低温苛刻条件下，生物质气凝胶的机械性能会减弱，变得极其脆弱，并失去功能。在此，我们报道了一种由纤维素纳米纤维（约200纳米）和明胶制成的具有层状纳米结构（约1微米）的多功能生物质气凝胶，它在从室温到超低温的范围内都表现出出色的弹性（在液氮中可反复弯曲、扭曲或压缩）。所得气凝胶在正常和极端环境中均表现出优异的有机溶剂吸收、热红外隐身和隔热性能。即使在干冰温度（-78°C）下，该气凝胶也能以与室温相同的方式选择性地反复吸收有机溶剂，且吸收量高（90-177克/克）。在-196至80°C的宽温度范围内实现了优异的隔热和红外隐身性能。此外，这种气凝胶兼具超低密度（约6毫克/立方厘米）、生物可降解性、阻燃性和性能稳定性等优点，使其成为苛刻条件下多功能应用的理想候选材料。这项工作极大地拓宽了生物质气凝胶的应用温度窗口，并为开发用于极端条件下各种应用的机械坚固的生物质气凝胶提供了思路。
