Thermal-based Zinc-Oxide-Coated Smart Fabric for Thermochromic Applications

The present study focuses on developing a thermochromic device with a flexible substrate through the coating of cotton fabric with ZnO (Zinc oxide) by solvothermal synthesis technique. Here, ZnO is used as the thermochromic layer for the fabrication work, and it is suitable for textile and wearable applications as it is non-toxic to human skin. This device is designed and fabricated in order to gain better insight into the role of ZnO in thermochromic applications. Here, 3D nanostructures of ZnO are grown on the surface of cotton fabric using a simple and cost-effective solvothermal synthesis approach. The coated fabrics are investigated to determine their structure, morphology, composition, electrical, optical and emissivity properties using an X-ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM), current-voltage (I-V) characteristics, ultraviolet protection factor (UPF) etc. From the morphology study, uniformly packed ZnO nanorods with growth in the c -axis direction are observed. The ZnO nanostructures are known to have excellent UPF when exposed to solar radiation and showed UPF value of 112.48. It is found that coated fabrics have increased electrical conductivity under optical excitations and also enhanced the reflectance. Moreover, based on the emissivity analysis coated ZnO cotton fabric showed the emissivity of 0.95, which is higher and has greater radiation protection than that of bare cotton fabric. Hence, the developed thermochromic device has potential for use in the future in textile and wearable based thermochromic application.