Sandwich-Structured Coating for Ultraviolet Protection and Thermal Management Applications

During the day, exposure to UV radiation poses risks to human health, while managing heat exchange is important for comfort in protective textiles. Recently, infrared-reflective materials have attracted attention, particularly for reducing the infrared transmission and moderating the thermal emission. In this study, titanium dioxide/copper-aluminum/titanium dioxide (TiO₂/Cu-Al/TiO₂, TCAT) sandwich-structured coatings were deposited on polyester fabric using magnetron sputtering. Deposition times (40 and 90 s) were varied to adjust Al and Cu layer thicknesses between 20 and 55 nm, and the resulting films were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, UV-vis spectroscopy, and thermal imaging. The coatings retained moderate visible transmittance on glass, whereas on woven polyester fabric, they formed an optically dense barrier with near-zero UV transmittance, suppressing light penetration across the visible to near-infrared (VIS-NIR) range. In conjunction with the emissivity-aware interpretation of thermography, these results substantiate substrate-independent UV shielding and optical/thermal barrier behavior of the TCAT multilayer. Thermal imaging qualitatively indicated reduced apparent surface temperature for coated fabrics compared to uncoated ones, suggesting partial thermal shielding. These results demonstrate the feasibility of integrating multifunctional coatings into daily-use polyester textiles, offering effective UV protection and the potential for thermal management in protective applications.