Low temperature hydrothermal fabrication of tungsten trioxide on the surface of wood with photochromic and superhydrophobic properties

Abstract

Tungsten trioxide (WO3), which is a semiconductor, was hydrothermally synthesized onto the surface of wood. After the in-situ synthesis of WO3 nanoparticles on the wood surface, the wood exhibited photochromic and superhydrophobic properties. The WO3 nanostructures were fabricated on wood surface through a two-step hydrothermal process at 90 °C or 120 °C for 6 h. Chemical composition, crystalline structures, and morphologies of the WO3-coated wood were characterized. The results indicated that the amount of WO3 nanostructures on the surface of the wood substrate was 12.89 wt.%. Meanwhile, the WO3 nanostructures were composed of fine nanoparticles and highly crystallized by SEM and XRD analysis. When the sample was irradiated under ultraviolet (UV) light (365 nm), there was an obvious color change after 10 min (ΔE). The water contact angle measurements demonstrated that the fluorosilane modified WO3-coated wood surfaces possessed a superhydrophobic behavior with a contact angle of 152°. The sliding angle was less than 10°. Photochromic and superhydrophobic properties were achieved by a facile process, which could contribute to the development of functional wood with an aesthetic coloring.