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In combat casualty care one of the more challenging objectives is keeping the patient warm and preventing hypothermia. Especially in harsh environments, such as northern climate regions and the arctic, keeping casualty from freezing before they can be transported to a field hospital proves to be challenging. 1 Here we describe the potential of a new inductively heatable fabric for the development of novel safety blankets that may be used in concurrency with already available solutions such as radiative reflective sheets and localized chemical heating units.A very fast and efficient way of heating surfaces is via induction, where heat can be generated directly in a magnetic material. When ferromagnetic nanoparticles are introduced into an alternating magnetic field, magnetization and demagnetization phenomena lead to heat generation within these particles via hysteresis losses.2 Depending on the applied magnetic field strength and oscillation frequency, the pure particles can be heated up to 600°C within seconds with a power conversion efficiency between 70 – 90%.3 Heating to lower temperatures, such as 30 – 35°C for human application, can be achieved very efficiently at low power demand. Another benefit of ferromagnetic nanoparticles is that they can be integrated into suitable binders for coating of surfaces, impregnation of fabrics or integration into composites, which enables the addition of inductive heating properties to non-magnetic materials.4 Depending on temperatures that need to be reached, the material composition and the applied field strength and oscillation frequency of the induction setup can be tuned.We have developed a proof-of-concept demonstrator for using inductive heating in a novel type of fabric that can be used as safety blanket for preventing hypothermia in combat casualty care. We have developed a ferromagnetic nanoparticle, based on magnetite (Fe3O4) with magnetic properties optimized for the use in fabric that needs to be heated to 35°C. We have developed a method to surface functionalize the particles for integration into a polyvinyl butyral (PVB) matrix and impregnate a cotton fabric with said nanocomposite material. We could show that a pure PVB nanocomposite with 0.5 wt% magnetite could be heated with a temperature increase of 35°C within 26 sec when an alternating magnetic field of 77 mT is applied at a frequency of 238 kHz. Furthermore, we impregnated a cotton cloth with camouflage print with such a PVB nanocomposite. The amount of applied PVB layer on the fabric was approximately 5 wt% regarding the mass of the fabric. For demonstration purposes, a 5x5 cm2 impregnated fabric was subjected to an alternating magnetic field of 77 mT at 238 kHz via a flat induction coil. The temperature evolution within the fabric was monitored and recorded via a thermal camera. Here we could show successful heating from 20°C to 55°C within 15 sec, representing a 35°C temperature increase (figure 1).Abstract A28 Figure 1a) Temperature evolution in nanocomposite impregnated cloth whilst heating via an induction setup applying an alternating magnetic field of 77 mT at a frequency of 238 kHz (inlay shows impregnated cloth). b) Lab setup of induction system with flat coil for heating impregnated cloth samplesAcknowledgement The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. The research was internally funded by TNO via the exploratory research program.References Sullivan-Kwantes W, Haman F, Kingma BRM, Martini S, Gautier-Wong E, Chen KY, Friedl KE. Human performance research for military operations in extreme cold environments. J Sci Med Sport . 2021;24:954–962. doi: 10.1016/j.jsams.2020.11.010Shaterabadi Z, Nabiyouni G, Soleymani M. Physics responsible for heating efficiency and self-controlled temperature rise of magnetic nanoparticles in magnetic hyperthermia therapy. Prog Biophys Mol Biol. 2018;133: 9–19. doi: 10.1016/j.pbiomolbio.2017.10.001Mündlein M, Schug B, Wintzheimer S, Mandel K. Facile synthesis of magnetic nanoparticles optimized towards high heating rates upon magnetic induction. J Magn Magn Mater. 2019;488:165350. doi: 10.1016/j.jmmm.2019.165350Raczka T, Wolf A, Reichenstein J, Stauch C, Schug B, Müssig S, Mandel K. Influence of magnetic interactions in iron oxide nanoparticle polymer composites on magnetism and induction heating. J Magn Magn Mater. 2024;598:172042. doi: 10.1016/j.jmmm.2024.172042