Enhanced ultraviolet shielding performances of TiO₂ nanorods in different crystalline structures and illite-loaded composites

Abstract

With deeper understanding of the harm of ultraviolet (UV) ray radiation, more and more attentions have been paid on developing UV shielding agents with better price-quality ratio. In this article, TiO₂ nanorods with three types of crystalline structures (anatase, brookite, and rutile) and their composites with natural illites were prepared by hydrothermal method under appropriate glycolic acid and pH environment. The resultant samples were analyzed by XRD, SEM, XPS, TEM, UV–vis spectrum and UV aging testing. The results confirm that both the aspect ratio and the crystalline structures of TiO₂ nanorods greatly affect the UV shielding performances of TiO₂ films. Compared with anatase and brookite, rutile TiO₂ nanorods with the best aspect ratio (around 3.5) display the best UV shielding performance. Furthermore, after loaded by natural illite micro-sheets, the illite-TiO2 composites display better UV shielding performance than pure TiO₂ nanorods, due to the physical reflection effect and interfacial coupling effect of illite micro-sheets. When the loading amount ratio reaches to 1:1, the illite-TiO2 composite loaded with rutile TiO₂ nanorods display the best UV shielding performance. And such coating is confirmed to be greatly helpful in protecting cotton fabrics from fractures caused by UV aging. The best illite-TiO2 composite can significantly increases the retention tensile strength of cotton fabrics by 47 % against UV radiation. The resultant novel illite-TiO2 composite provides a promising method to product better UV shielding agents for practical applications, which displays lower cost, nearly non-toxic, better aqueous dispersion, controlled UV–vis spectral characteristics, and higher UV shielding performances.