Li Changfeng, Wang Ge, Peng Mengyue, Liu Chenwei, Feng Tangfeng, Wang Yunfei, Qin Faxiang
Institute for Composites Science Innovation (InCSI), School of Materials Science and Engineering, Zhejiang University, 38 Zheda Road, Hangzhou, 310027, P.R. China.
ACS Appl Mater Interfaces. 2024 Aug 14;16(32):42448-42460. doi: 10.1021/acsami.4c07084. Epub 2024 Jul 30.
Reconfigurable metamaterial absorbers (MAs), consisting of tunable elements or deformable structures, are able to transform their absorbing bandwidth and amplitude in response to environmental changes. Among the options for building reconfigurable MAs, origami/kirigami structures show great potential because of their ability to combine excellent mechanical and electromagnetic (EM) properties. However, neither the trial-and-error-based design method nor the complex fabrication process can meet the requirement of developing high-performance MAs. Accordingly, this work introduces a deep-learning-based algorithm to realize the fast inverse design of origami MAs. Then, an accordion-origami coding MA is generated with reconfigurable EM responses that can be smoothly transformed between ultrabroadband absorption (5.5-20 GHz, folding angle α = 82°) and high reflection (2-20 GHz, RL > -1.5 dB, α = 0°) under -polarized waves. However, the asymmetric coding pattern and accordion-origami deformation lead to typical polarization-sensitive absorbing performance (2-20 GHz, RL > -4 dB, α < 90°) under -polarized waves. For the first time, a kirigami polarization rotation surface with switchable operation band is adapted to balance the absorbing performance of accordion-origami MA under orthogonal polarized waves. As a result, the stacked origami-kirigami MA maintains polarization-insensitive ultrabroadband absorption (4.4-20 GHz) at β = 0° and could be transformed into a narrowband absorber through deformation. Besides, the adapted origami/kirigami structures possess excellent mechanical properties such as low relative density, negative Poisson's ratio, and tunable specific energy absorption. Moreover, by modulating the PEDOT:PSS conductive bridges among MXene nanosheets, a series of low-concentration MXene-PEDOT:PSS inks (∼46 mg·mL) with adjustable square resistance (5-32.5 Ω/sq) are developed to fabricate the metamaterials via screen printing. Owing to the universal design scheme, this work supplies a promising paradigm for developing low-cost and high-performance reconfigurable EM absorbers.
可重构超材料吸波器（MAs）由可调元件或可变形结构组成，能够根据环境变化改变其吸收带宽和幅度。在构建可重构MAs的选项中，折纸/剪纸结构因其能够结合优异的机械和电磁（EM）特性而显示出巨大潜力。然而，基于试错的设计方法和复杂的制造工艺都无法满足开发高性能MAs的要求。因此，这项工作引入了一种基于深度学习的算法来实现折纸MAs的快速逆向设计。然后，生成了一种手风琴折纸编码MA，其具有可重构的电磁响应，在 - 极化波下可以在超宽带吸收（5.5 - 20 GHz，折叠角α = 82°）和高反射（2 - 20 GHz，RL > -1.5 dB，α = 0°）之间平滑转换。然而，不对称的编码模式和手风琴折纸变形导致在 - 极化波下具有典型的偏振敏感吸收性能（2 - 20 GHz，RL > -4 dB，α < 90°）。首次采用具有可切换工作频段的剪纸偏振旋转表面来平衡手风琴折纸MA在正交极化波下的吸收性能。结果，堆叠的折纸 - 剪纸MA在β = 0°时保持偏振不敏感的超宽带吸收（4.4 - 20 GHz），并且可以通过变形转变为窄带吸波器。此外，适配的折纸/剪纸结构具有优异的机械性能，如低相对密度、负泊松比和可调的比能量吸收。此外，通过调制MXene纳米片之间的PEDOT:PSS导电桥，开发了一系列具有可调方阻（5 - 32.5 Ω/sq）的低浓度MXene - PEDOT:PSS油墨（~46 mg·mL），以通过丝网印刷制造超材料。由于通用的设计方案，这项工作为开发低成本和高性能的可重构电磁吸波器提供了一个有前景的范例。
