LAUSR

Here, we investigate a wearable-based IR and thermal stealth structure that effectively blocks IR and thermal radiation from a human body or device using a polyurethane–antimony tin oxide (PU–ATO) composite fiber. The aging time of the ATO sol prepared by a sol–gel method, and the concentration of ATO with respect to that of the PU matrix were optimized to prepare PU–ATO composite fibers that simultaneously have an appropriate mechanical strength (strength of ~4 MPa and strain of ~340%) and IR- and thermal radiation-shielding properties with ~98% IR light, as determined by Fourier transform IR spectroscopic studies. The fabricated PU–ATO composite fiber showed stable IR- and thermal radiation-shielding properties even when exposed to ten cycles of repeated temperature changes of −20 and +80 °C and long-term temperature changes for 30 days. In addition, the surface of the PU–ATO composite fiber was rendered hydrophobic to prevent the distortion of the IR and thermal radiation due to the wetting of the PU–ATO composite fiber with absorbed water. The PU–ATO composite fiber-based textile proposed herein can be applied in wearable IR- and thermal radiation-shielding technologies to shield IR signals generated by objects of diverse and complex shapes. A material that makes us invisible to infrared cameras has been developed by researchers in South Korea. Even in total darkness, the heat that our body produces can give away our position. Clothing that masks this infrared radiation to make the wearer indistinguishable from the background is therefore useful in stealth applications. Sang Yoon Park from Seoul National University, Sanghyun Ju from Kyonggi University, Suwon, and their colleagues have developed a fiber made from a combination of a polymer known as polyurethane and a metal oxide, antimony tin oxide (ATO). The fibers block thermal radiation because the ATO scatters infrared light. The team used a wet-spinning technique to create a number of different composite fiber with varying ATO concentrations so that they could optimize their useful lifetime. The polyurethane–antimony tin oxide (PU–ATO) composite fibers makes infrared (IR) radiations emitted by an object to be as similar as possible to ambient background radiation such that an IR detection sensor fails to distinguish the target object. Hydrophobic surface of the PU–ATO composite fiber prevent the distortion of the IR and thermal radiation caused by the wetting of the PU–ATO composite fiber with water. The PU–ATO composite fiber-based textile can be applied in wearable IR- and thermal radiation-shielding technologies to shield IR signals generated by objects of diverse and complex shapes.