Bioinspired Porous Anodic Alumina/Aluminum Flake Powder for Multiband Compatible Low Detectability

Abstract

Continuous development and advancement in modern detection technologies have increased the demand for multiband (e.g., visual and infrared) compatible camouflage. However, challenges exist in the requirements of incompatible structure resulting from the adaptation to different camouflage effects. This study is inspired by the light absorption structure of butterfly wing scales and demonstrates a porous anodic alumina/aluminum flake powder material prepared by a microscopic powder anodic oxidation technique for visual and infrared camouflage. The fabricated structures manipulate a compromise condition for visual camouflage by low reflectance (R̅ 400-800nm = 0.32) and dual-band infrared camouflage by low emission (ε ̅ 3-5μm = 0.081 and ε ̅ 8-14μm = 0.085). Further, the characteristic of short-range disorder in these bioinspired structures allows maintenance of the camouflage performance under omnidirectional detection (0−60°). This study provides new insight and a feasible method for coordinated manipulation of electromagnetic waves via bioinspired structural design and improved fabrication.

Scalable, Color‐Matched, Flexible Plasmonic Film for Visible–Infrared Compatible Camouflage

“…Meanwhile, the material of the middle dielectric film is alumina, which is almost transparent in the mid‐infrared region, to avoid the effect on infrared camouflage. [ 6 ] When the top metal layer is Ag, the reflection simulation result suggests that narrowband absorbers appear at the wavelength of the reflective valleys and show maximum peak‐to‐valley fluctuation (Figure 1b ). [ 31 ] Apart from the sharp absorption peaks, the reflectivity stays close to 1 in the rest of the wavelength, which results in little perceptible color in the typical F–P nanocavity structure (Figure 1c ).…”

“…Therefore, it is necessary to reduce the detectability of a target at different detectable wavelengths by adjusting its characteristic signal to be the same or comparable to the background environment. [ 4 , 5 , 6 ] With the popularity of infrared detection and surveillance systems, the visible and mid‐infrared ranges are the two most prevalent and important wavebands in camouflage technology. [ 7 , 8 , 9 ] To achieve spectra modulation in both visible and infrared ranges, materials with nanostructures have been explored and promising research progress has been accomplished.…”

Structure–Activity Relationship in Microstructure Design for Electromagnetic Wave Absorption Applications

“…Multispectrum-compatible stealth MAMs are gradually entering the public's view. [162][163][164] Inspired by moth eyes, biomimetic hierarchical metamaterials not only have low infrared (IR) emissivity and MA, but also have hydrophobicity (Figure 7d). [165] Based on the research of carbon black (CCB) filled polyethylene (PE) composite films, a multispectrum-integrated metamaterial with broadband and strong absorption capacity in the microwave, visible light, and near-infrared bands was designed (Figure 7e).…”

Ultrawide Spectra Camouflage Coatings from Metallic Flake Powder

“…PAA/AFP was fabricated by the micropowder anodic oxidation technique. 49 For the fabrication of bioinspired porous structure, the original AFP was wrapped in porous hydrophilic carbon cloth and connected to the positive pole of the power supply by a discoid platinum electrode, which was pressed on the carbon cloth. The negative pole was connected to the Pt sheet electrode.…”