Development of multifunctional self-cleaning and UV blocking cotton fabric with modification of photoactive ZnO coating via microwave method

Abstract

Abstract A new self-cleaning cotton fabric coated with zinc oxide (ZnO) was obtained via a facile and effective microwave method. The solution pH was a key factor in determining the morphology of ZnO crystal growth on the cotton fibers: rod structures were apt to be formed at pH 4–5, whereas flake and flower-like structures were preferentially formed at higher solution pHs of 6–7 and 10–11, respectively. It is proved that the photocatalytic and wettability performances of ZnO could be efficiently transferred to cotton fabric, leading to a preeminent UV-blocking and self-cleaning cotton fabric. The identified UV protection factors (UPFs) indicate the excellent UV-blocking properties of the ZnO-coated textile fabric synthesized at pH 6–7, 8–9 and 10–11 with UPFs of 222.52, 162.68 and 202.57, respectively. The ZnO coating layer on the cotton fabric significantly improved the wetting behavior of the fabric, such as water absorption speed, thereby affording a self-cleaning ability for the ZnO-coated cotton fabrics. This ability was checked according to the removal degree of coffee stain under UV irradiation at different humidities (30–90% RH). The coffee stains on the ZnO-coated cotton fabrics were almost removed after 15 h without needing any water or detergent and the highest removal effect was observed at 90% humidity.