A\nFe<sup>3+</sup>-Doped TiO<sub>2</sub> Superhydrophilic\nCoating with Transparent and Long-Lasting Antifogging Properties Constructed\nBased on Nanostructured Antireflective and Capillary Anchoring Effects

Superhydrophilic\nsurfaces have attracted great interest in antifogging\napplications. However, balancing long-lasting superhydrophilicity\nand high transparency on antifogging surfaces remains a serious problem\nto be solved. The objective of this work is to prepare superhydrophilic\ncoatings with transparent and long-lasting antifogging properties.\nIn the design, a three-step method was used to obtain the target coatings:\n(1) magnetron sputtering deposition of a TiN film to provide high\nintensity, (2) anodic oxidation of the TiN film to obtain TiO<sub>2</sub> nanoparticles intended for nanostructured antireflective\nand capillary structures, and (3) the sol–gel method for the\npreparation of Fe<sup>3+</sup>-doped TiO<sub>2</sub> coatings using\nspin-coating in order to achieve superhydrophilicity. The nanostructures,\ndue to their subwavelength dimensions, not only provide high transparency\nbut also recoverable superhydrophilicity owing to the presence of\na capillary anchoring effect that prevents the coating from dissolving\nand peeling off after soaking. The doping of Fe<sup>3+</sup> broadened\nthe photoresponse range and maintained the long-lasting superhydrophilicity.\nTests showed that the 2 mol % Fe<sup>3+</sup>-doped TiO<sub>2</sub> coating with nanostructures exhibited the highest transparency,\nlongest-lasting superhydrophilicity, and antifogging properties. Furthermore,\nthe coating provided excellent self-cleaning properties, as well as\nmechanical and chemical stability.