Lei Chuxin, Zhang Yongzheng, Liu Dingyao, Wu Kai, Fu Qiang
College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, P. R. China.
Key Laboratory for Soft Chemistry and Functional Materials of Ministry of Education, Department of Polymer Science and Engineering, School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, P. R. China.
ACS Appl Mater Interfaces. 2020 Jun 10;12(23):26485-26495. doi: 10.1021/acsami.0c07387. Epub 2020 May 28.
Polymer-based electromagnetic interference (EMI) shielding materials possess many irreplaceable advantages than metals, such as superior flexibility, easy processing, and low density. However, impeded by their limited mechanical properties, inferior temperature resistance and unsatisfactory electrical conductivity, it is still challenging to extend their shielding applications under some extreme conditions, i.e., <-50 or >200 °C. Herein, we report an ultrathin, highly robust, superflexible, and temperature-stable film via engineering a worm-like aramid nanofiber (ANF) into the rod-like microscopic configuration, followed with self-assembly with TiCT (MXene) into a hierarchical brick-and-mortar architecture. With stiff and symmetric aromatic rings fully straightened and well packed into a crystalline form in the backbone, this rod-like ANF enables an augmented network with effective energy dissipation, resulting in the metal-like mechanical properties, i.e., unprecedented tensile strength (300.5 MPa), high Young's modulus (13.6 GPa), and excellent folding endurance (>10 000 times). More significantly, this MXene/ANF composite film with outstanding specific EMI shielding effectiveness (8814.5 dB cm g) and flame retardancy performs a broad range of operations in the temperature range from -100 °C (355 MPa) to 300 °C (136 MPa), in which >99% electromagnetic waves could be eliminated; this promises its potential EMI shielding applications even in some extreme conditions.
基于聚合物的电磁干扰（EMI）屏蔽材料比金属具有许多不可替代的优势，如卓越的柔韧性、易于加工和低密度。然而，由于其有限的机械性能、较差的耐温性和不令人满意的导电性，在一些极端条件下，即<-50或>200°C下扩展其屏蔽应用仍然具有挑战性。在此，我们通过将蠕虫状芳纶纳米纤维（ANF）设计成棒状微观结构，然后与TiCT（MXene）自组装成分层的砖石结构，报道了一种超薄、高度坚固、超柔韧且温度稳定的薄膜。这种棒状ANF的刚性和对称芳环在主链中完全伸直并紧密堆积成晶体形式，形成了一个具有有效能量耗散的增强网络，从而具有类似金属的机械性能，即前所未有的拉伸强度（300.5 MPa）、高杨氏模量（13.6 GPa）和出色的折叠耐久性（>10000次）。更重要的是，这种具有出色的比EMI屏蔽效能（8814.5 dB cm g）和阻燃性的MXene/ANF复合薄膜在-100°C（355 MPa）至300°C（136 MPa）的温度范围内具有广泛的适用性，其中>99%的电磁波可以被消除；这预示着即使在一些极端条件下，它也具有潜在的EMI屏蔽应用前景。
