Lim Gwendolyn Jia Hao, Yang Zeshi, Hou Yi, Sugumaran Pon Janani, Qiao Zhi, Ding Jun, Yan Wentao, Yang Yong
National University of Singapore, 5A Engineering Drive 1, 117411, Singapore.
Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, 117575, Singapore.
ACS Appl Mater Interfaces. 2022 Jul 13;14(27):31267-31276. doi: 10.1021/acsami.2c06567. Epub 2022 Jun 29.
One-dimensional (1D) fibers have been widely used in composites reinforcement for microwave attenuation due to their outstanding mechanical and electromagnetic properties, especially in the axial direction. However, the precise control of fiber alignment in a polymer matrix remains a challenge. In this work, we successfully demonstrated the well-controlled alignment of silicon carbide nanowires (SiCNW) in a silicone matrix by using direct ink writing (DIW)-based 3D printing. It is proven that the printed multilayer material with fiber alignment could show a dramatic improvement in both reflection loss (RL) and effective attenuation bandwidth (EAB, RL < -10 dB). In particular, a uniaxial in-plane orientation is found to be the optimal alignment among other planar and also out-of-plane orientations. Benefiting from the optimized alignment, the 3D-printed SiC composite could show an EAB (∼6.4 GHz)1.6 times broader than that of the randomly mixed composite at the same thickness without alignment, associated with a minimum RL of -48 dB at 14.3 GHz. In addition, it is demonstrated that DIW could print different materials, such as SiCNW and multiwall carbon nanotube (MWCNT), in alternating layers for multiple-frequency-band attenuation benefiting from the distinct property of each material. Considering the one-step control of fiber alignment and material selectivity, DIW could play an important role in materials design for high-efficiency microwave attenuation.
一维（1D）纤维因其优异的机械和电磁性能，特别是在轴向方向上，已被广泛用于复合材料增强以实现微波衰减。然而，在聚合物基体中精确控制纤维排列仍然是一个挑战。在这项工作中，我们通过基于直接墨水书写（DIW）的3D打印成功地展示了碳化硅纳米线（SiCNW）在有机硅基体中的良好排列控制。事实证明，具有纤维排列的印刷多层材料在反射损耗（RL）和有效衰减带宽（EAB，RL < -10 dB）方面都能有显著改善。特别是，发现单轴面内取向在其他平面和非平面取向中是最佳排列。受益于优化的排列，3D打印的SiC复合材料在相同厚度且无排列的情况下，其EAB（约6.4 GHz）比随机混合复合材料宽1.6倍，在14.3 GHz时的最小RL为-48 dB。此外，还证明了DIW可以交替层打印不同材料，如SiCNW和多壁碳纳米管（MWCNT），以实现多频段衰减，这得益于每种材料的独特性能。考虑到纤维排列和材料选择性的一步控制，DIW在高效微波衰减的材料设计中可以发挥重要作用。
