CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei, Anhui230027, People's Republic of China.
CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Precision Machinery and Instrumentation, University of Science and Technology of China, Hefei, Anhui230027, People's Republic of China.
ACS Nano. 2023 Feb 28;17(4):3620-3631. doi: 10.1021/acsnano.2c10460. Epub 2023 Jan 30.
In nature, many insects have evolved sclerotic cuticles to shelter their soft bodies, which are considered as "body armor". For beetles, the epidermis is composed of cross-linked intertwined fiber structures; such a fiber network structure could provide an anti-impact function for composites. Aramid nanofibers (ANFs) are of great interest in various applications due to their 1D nanoscale, high aspect ratio, excellent strength and modulus, and impressive chemical and thermal stability. In this paper, a kind of ANF network is prepared by a layer-by-layer assembly method. The enhancing ANF networks are developed by introducing carboxylated chitosan acting as a hydrogen-bondin donors as well as a soft interlocking agent (C-ANFs). As a result of the formation of a nanostructure and the hydrogen-bond interactions, the assembled C-ANF networks presented a high tensile strength (551.4 MPa) and toughness (4.0 MJ/m), which is 2.41 times and 32.69 times those of neat ANF networks, respectively. The excellent mechanical properties endow C-ANF networks with distinguished anti-impact performance. The specific dissipated energy after mass normalization reaches 7.34 MJ/kg, which is significantly superior to traditional protective materials such as steel and Kevlar composites. A nonlinear spring model is also used to explain the mechanical behavior of C-ANF networks. In addition to anti-impact protection, C-ANF networks can realize more than 99% of UV irradiation absorption and have excellent thermal stability. The chemical stability of C-ANF networks make them survive in acid and alkali environments. The above characteristics show that C-ANF networks have great application value in multiscale protection scenarios under an extreme environment.
在自然界中，许多昆虫进化出了坚硬的外骨骼来保护它们柔软的身体，这被认为是“盔甲”。对于甲虫来说，表皮由交联交织的纤维结构组成；这种纤维网络结构可以为复合材料提供抗冲击功能。芳纶纳米纤维（ANF）由于其 1D 纳米尺度、高纵横比、优异的强度和模量以及令人印象深刻的化学和热稳定性，在各种应用中引起了极大的兴趣。在本文中，通过层层组装方法制备了一种 ANF 网络。通过引入作为氢键供体和软互锁剂的羧化壳聚糖来增强 ANF 网络（C-ANF）。由于形成了纳米结构和氢键相互作用，组装的 C-ANF 网络表现出高拉伸强度（551.4 MPa）和韧性（4.0 MJ/m），分别是纯 ANF 网络的 2.41 倍和 32.69 倍。优异的力学性能使 C-ANF 网络具有出色的抗冲击性能。归一化后比能达到 7.34 MJ/kg，明显优于传统防护材料如钢和凯夫拉复合材料。还使用非线性弹簧模型来解释 C-ANF 网络的力学行为。除了抗冲击保护，C-ANF 网络还可以实现超过 99%的紫外线辐射吸收，具有出色的热稳定性。C-ANF 网络的化学稳定性使它们能够在酸碱环境中生存。上述特性表明，C-ANF 网络在极端环境下的多尺度保护场景中具有巨大的应用价值。
