Bioinspired Metamaterials: Multibands Electromagnetic Wave Adaptability and Hydrophobic Characteristics

Abstract

the light-responsive properties also have excellent adaptability to the environment. [7] Under the inspiration of these controllable optical properties, a variety of advanced material systems have been proposed significantly. [7,8] However, researchers were simply concentrated in a specific waveband due to the great difficulty to achieve the compatibility of multispectral properties, which greatly hinders advance science and the application fields expanding of novel photonic materials. For example, in order to avoid the detection of microwave radar, infrared detector, and visual observation, the stealth materials on military armament have been separately developed during microwave, infrared, and visible light range; [9][10][11] but the above stealth properties were difficult to be compatible in one weapon, thus, the problem of perfect stealth (stealth during full wavebands) is still not solved to date. Moreover, the material degradation by ultraviolet (UV) radiation also needs to be settled urgently because the weapons are exposed to sunlight all year round. Although metamaterials (MMs) researchers have conducted multibands studies, [12] such as optically transparent microwave absorbing materials, [13] multispectral absorption MMs, [14] and multibands resonators, [15] etc., only two or three bands were involved, and the multibands compatibility has not been deeply explored. When devices worked in real environments, dust particles accumulated on its surface over time, which would have an adverse effect on its light manipulation performance. In order to avoid this problem, it is desirable to integrate a self-cleaning ability induced by hydrophobic property of material into the equipment. [16] In this context, a hierarchical structure model of moth compound eye that might manipulate multibands EMWs was found here, as shown in Figure 1a. [17,18] This is a noctuid moth living in Heilongjiang Province of China; the hierarchical and sub-wavelength structures that are arranged in a highly ordered array of its eye surface could suppress the reflection of light to avoid detection by nocturnal predators and to see clearly in darkness, which is based on rigorous coupled wave analysis (RCWA) and finite difference time domain (FDTD) methods, [19] as well as relative research on moth eye model. [18,20] This feature makes the moth-eye model one of the most effective antireflective structures in nature. Although various photonic devices inspired by natural materials have been developed, there is no research focusing on multibands adaptability, whichis not conducive to the advancement of materials science. Herein, inspired by the moth eye surface model, state-of-the-art hierarchical metamaterials (MMs) used as tunable devices in multispectral electromagnetic-waves (EMWs) frequency range, from microwave to ultraviolet (UV), are designed and prepared. Experimentally, the robust broad bandwidth of microwave absorption greater than 90% (reflection loss (RL) < −10 dB) covering almost entire X and Ku bands (8.04-17.88 GHz) under a de...

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A Nano-Micro Engineering Nanofiber for Electromagnetic Absorber, Green Shielding and Sensor

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Solvent-Free Synthesis of Ultrafine Tungsten Carbide Nanoparticles-Decorated Carbon Nanosheets for Microwave Absorption

“…Electromagnetic (EM) pollution has become a global concern owing to its potential threats in physical health, equipment operation, and information security [1][2][3][4]. Although the shielding strategy can produce powerful effectiveness in individual protection, the reflection principle therein makes it invalid to alleviate those side effects of EM technology [5,6].…”