Optical properties of water absorbing textiles for camouflage

Abstract

Background matching is an essential form of camouflage, adopted by humans especially within military applications in terms of signature reduction. Recent sensor developments have created a need for novel camouflage effective in shortwave infrared (SWIR). The absorption of electromagnetic radiation in SWIR is heavily influenced by water. In a forest environment, the water content in plants is of considerable importance. Therefore, it can be inferred that fabrics with higher moisture levels would exhibit reduced detectability in SWIR wavelengths when compared to their dry counterparts. In this study, the optical properties of different fabrics, both in their dry and hydrated state, was evaluated with SWIR imaging and UV-VIS-NIR spectroscopy and compared to foliage. Two methods of hydration were used, water and nanocellulose. In addition, an assessment of the evaporation of water from the hydrated fabrics samples was carried out. Two fabrics were surface treated with hydrophobic compounds in order to modify the evaporation. The treatments included water-repelling agents and silica nanoparticles (SNPs). The hydrophobic surface modifications did not appear to prolong the evaporation of water from the studied fabrics. Hydrating the fabrics appears to transform the electro-optical signature to closely resemble foliage.

Fabrication of Multifunctional Tents Using Canvas Fabric

“…Örtenberg used hydrophobic chemicals to treat the fabric samples as mentioned in Figure and then compared the outcomes before and after treatment. , The findings show that, in comparison to their dry condition, hydrated textiles generally exhibit a lower reflectance in the shortwave infrared spectrum because of their high water absorption. , Nikwax, OrganoTex, water-repellent treatments, and SNPs functionalized with silane compounds were among the hydrophobic agents. , Improving the hydrophobicity of the cloth surfaces did not increase the water’s evaporation time . Though not significantly, the hydrogel and water-repellent Nikwax combination did demonstrate a modest decrease in water, evaporation. , …”

“…Camouflage has evolved naturally over thousands of years as a means of survival for both prey and predators. , This article’s objective is to assess canvas materials’ infrared (IR) camouflage (seen in Figure ) abilities of tents in terms of its ability to repel water and have antibacterial and air filtration capabilities. The tent is a type of shelter that has clothing sheets or materials thrown over it and is supported by a rope or pole frame, while smaller tents could be anchored to the ground or be standalone. , Small tents can be carried easily over long distances using boats or bikes or while backpacking. On the other hand, larger tents are heavier and usually moved using a car or some other vehicle .…”