Preparation of a water-absorbent mesoporous material and film to simulate the infrared spectrum of plants

Abstract

Hyperspectral imaging poses great challenges to traditional camouflage materials, primarily because there is a huge difference between the reflectance spectra of camouflage materials and natural plants in the 1400–2000 nm band. The difficulty of simulating the natural plant spectrum lies in reproducing the absorption peak of water by increasing the water content in a camouflage material. Herein, a mesoporous (MS) material is used to simulate the plant spectrum because such material can absorb and retain a large amount of water. MS was prepared via a two-step method using tetraethyl orthosilicate and tetrabutyl titanate. The characteristics of the as-prepared MS were examined via X-ray diffraction, transmission electron microscopy, ultraviolet–visible diffusion reflectance spectroscopy and nitrogen adsorption–desorption isotherms. In addition, a film was prepared using the fully absorbent mesoporous material, and the water content was determined via near-infrared spectroscopy and thermogravimetric analysis. The bonding between the mesoporous material and resin was examined via field emission gun scanning electron microscopy. The mechanical properties of the film were measured by a pendulum hardness tester and a cylindrical bending tester. The results indicate that low-temperature synthesis followed by high-temperature hydrothermal treatment is conducive to expanding the mesopore aperture, reaching a maximum of 23 nm. Moreover, the regular structure of the as-prepared titanium-containing mesoporous material is maintained under high hydrothermal temperature. The mesoporous film exhibits a good water absorption capacity of up to 80% by mass and can effectively simulate the spectrum of plants. The mechanical properties of the film are good, and the hardness of the film is related to the content of mesoporous powder. © 2023 Society of Industrial Chemistry.