Chen Yuan, Yu Zhengyang, Ye Yuhang, Zhang Yifan, Li Gaiyun, Jiang Feng
Chinese Academy of Forestry, Research Institute of Wood Industry, No. 1 Dongxiaofu Xiangshan Road, Haidian District, Beijing 100091, P.R. China.
Sustainable Functional Biomaterials Laboratory, Department of Wood Science, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
ACS Nano. 2021 Jan 26;15(1):1869-1879. doi: 10.1021/acsnano.0c10577. Epub 2021 Jan 15.
Compressible and superelastic 3D printed monoliths have shown great promise in various applications including energy storage, soft electronics, and sensors. Although such elastic monoliths have been constructed using some limited materials, most notably graphene, it has not yet been achieved in nature's most abundant material, cellulose, partly due to the strong hydrogen-bonding network within cellulose. Here, we report a 3D-printed cellulose nanofibril monolith that demonstrates superb elasticity (over 91% strain recovery after 500 cycles of compressive test), compressibility (up to 90% compressive strain), and pressure sensitivity (0.337 kPa) at 43% relative humidity. Such a high-performance CNF monolith is achieved through both hierarchical architecture design by 3D printing and freeze-drying and incorporation of hygroscopic salt for water absorption. The facile and efficient design strategy for a highly flexible CNF monolith is expected to expand to materials beyond cellulose and can realize much broader applications in flexible sensors, thermal insulation, and many other fields.
可压缩且超弹性的3D打印整体材料在包括能量存储、柔性电子和传感器在内的各种应用中展现出了巨大潜力。尽管已经使用一些有限的材料（最显著的是石墨烯）构建了这种弹性整体材料，但在自然界中最丰富的材料纤维素中尚未实现，部分原因是纤维素内部存在强大的氢键网络。在此，我们报告了一种3D打印的纤维素纳米原纤维整体材料，它在43%相对湿度下表现出卓越的弹性（压缩测试500次循环后应变恢复率超过91%）、可压缩性（高达90%的压缩应变）和压力敏感性（0.337 kPa）。这种高性能的CNF整体材料是通过3D打印和冷冻干燥的分级结构设计以及引入吸湿盐以吸收水分来实现的。这种用于高度柔性CNF整体材料的简便高效设计策略有望扩展到纤维素以外的材料，并可在柔性传感器、隔热及许多其他领域实现更广泛的应用。
