Beijing National Laboratory for Molecular Sciences, Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
Macromol Rapid Commun. 2018 Jul;39(14):e1700724. doi: 10.1002/marc.201700724. Epub 2018 Mar 8.
Aerogels are gels in which the solvent is supplanted by air while the pores and networks are largely maintained. Owing to their low bulk density, high porosity, and large specific surface area (SSA), aerogels are promising for many applications. Various inorganic aerogels, e.g., silica aerogels, are intensively studied. However, the mechanical brittleness of common inorganic aerogels has seriously restricted their applications. In the past decade, nanofibers have been developed as building blocks for the construction of aerogels to improve their mechanical property. Unlike traditional frameworks constructed by interconnected particles, nanofibers can form chemically cross-linked and/or physically entangled 3D skeletons, thus showing flexibility instead of brittleness. Therefore, excellent elasticity and toughness, ultralow density, high SSA, and tunable chemical composition can be expected for the polymer nanofiber-derived aerogels (PNAs). In this review, recent research progress in the fabrication, properties, and applications of PNAs is summarized. Various nanofibers, including nanocelluloses, nanochitins, and electrospun nanofibers are included, as well as carbon nanofibers from the corresponding organic precursors. Typical applications in supercapacitors, electrocatalysts for oxygen reduction reaction, flexible electrodes, oil absorbents, adsorbents, tissue engineering, stimuli-responsive materials, and catalyst carriers, are presented. Finally, the challenges and future development of PNAs are discussed.
气凝胶是一种凝胶，其中溶剂被空气取代，而孔和网络在很大程度上得以保留。由于其低体积密度、高孔隙率和大比表面积（SSA），气凝胶在许多应用中具有广阔的前景。各种无机气凝胶，例如二氧化硅气凝胶，受到了广泛的研究。然而，普通无机气凝胶的机械脆性严重限制了它们的应用。在过去的十年中，纳米纤维已被开发为构建气凝胶的构建块，以改善其机械性能。与由相互连接的颗粒构成的传统框架不同，纳米纤维可以形成化学交联和/或物理缠结的 3D 骨架，从而表现出柔韧性而不是脆性。因此，聚合物纳米纤维衍生气凝胶（PNAs）有望具有优异的弹性和韧性、超低密度、高 SSA 和可调节的化学成分。在这篇综述中，总结了 PNAs 的制备、性能和应用的最新研究进展。包括各种纳米纤维，如纳米纤维素、纳米壳聚糖和静电纺丝纳米纤维，以及来自相应有机前体的碳纳米纤维。介绍了在超级电容器、氧还原反应电催化剂、柔性电极、吸油材料、吸附剂、组织工程、刺激响应材料和催化剂载体等方面的典型应用。最后，讨论了 PNAs 的挑战和未来发展。
