Poor mildew resistance has limited the application of bamboo materials. In this work, ZnO/PMHS coatings were fabricated on bamboo timber surfaces by hydrothermal synthesis method and hydrophobic modification with poly(methylhydrogen)siloxane (PMHS). The surface chemical characteristics and microstructure of the bamboo before and after modification were investigated using Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and water contact angle (WCA). The morphology results indicated that ZnO on the surface of bamboo forms flower-like aggregations. The WCA of ZnO/bamboo increased from 65° to 142° after PMHS hydrophobic modification, indicating that the hydrophobicity of bamboo was significantly improved. The original bamboo had poor anti-mildew properties when exposed to Trichoderma viride, Aspergillus niger, and Penicillium citrinum. After depositing ZnO onto the surface of the bamboo, the anti-mildew properties were significantly improved. Furthermore, it was found that after PMHS hydrophobic modification, ZnO/bamboo had excellent anti-mildew properties when exposed to the three mold hyphae, which indicated that PMHS hydrophobic modification had a synergistic effect on the anti-mildew properties of bamboo with a ZnO coating.

The nanometer zinc complex, formed in chloride-urea ionic liquid (IL), was studied with the objective of enhancing the mildew resistance of bamboo. The nano-Zinc complex layer was coated on the bamboo surface by a simple and mild heating process. The SEM analysis revealed that the morphology of the nanometer Zinc complex layer on the bamboo surface varied with the reaction time of bamboo in zinc chloride (ZnCl2)/urea ionic liquid. The result of EDS and FTIR analysis showed that zinc and chlorine were successfully coated on the surface of bamboo. In this study, it was found that the optimum condition was 2 h of reaction with 1:2 molar ratio of zinc chloride to urea, where the nano-Zinc complex layer on the bamboo surface was the most uniform and dense to present the bamboo with the strongest mildew resistance. The infection value of Trichoderma viride, Aspergillus niger V. Tiegh, and Penicillium citrinum Thom after 28 day was 0.