Hydrothermal deposition and photoresponsive properties of WO3 thin films on wood surfaces using ethanol as an assistant agent

A novel nanoplate-like tungsten trioxide was grown on a wood substrate using a facile one-step ethanol-assisted hydrothermal method. The morphology, chemical composition, crystalline structure, optical properties, thermostability, wettability and roughness of the WO 3 -treated woods were investigated. The results showed that the uniform WO 3 nano-plates exhibited an edge length of 1553   nm and a thickness of 102   nm. These structures were observed to be highly crystallized with hexagonal structures. The X-ray photoelectron spectroscopy (XPS) and Raman spectrum (RS) analysis demonstrated that the pure WO 3, without other impurities, could be grown on a wood substrate. The as-obtained product appeared a remarkable blue shift than the pristine wood by UV–vis analysis and had an obvious color response to UV light irradiation at 365   nm. The thermogravimetry (TG) analysis showed that the maximum degradation rate of the WO 3 -treated wood exhibited slower degradation rates when compared to the native wood control. Through the octadecyltrichlorosilane (OTS) treatment, the as-fabricated product exhibited a water contact angle (WCA) of 152°, indicative of its superhydrophobic property, which was ascribed to the low surface energy of OTS and the large surface roughness of the product.