Preparation and Superhydrophobicity of Nano-Al-Coated Wood by Magnetron Sputtering Based on Glow-Discharge Plasma

A superhydrophobic coating on wood can effectively improve the hydrophobicity and service life of wood. In this study, an Al superhydrophobic nano-coating was constructed on the transversal section of poplar wood by magnetron sputtering based on glow-discharge plasma. The structure, microscopic morphology, surface elements, and hydrophobic properties were characterized and tested. When coated for 20 s, the water contact angle on the sample surface can reach 148.9°. When coated for 30 min, the Al-coated wood had a contact angle of 157.3°, which could maintain excellent superhydrophobic properties for 300 s. The sputtered Al nanoparticles were uniformly distributed on the wood surface and formed nanoclusters. Plenty of voids between the clusters can trap air and block contact between water droplets and the coating, making the coating obtain superhydrophobic properties. When the coating time was 60 min, the characteristic peak of the Al (111) crystal plane appeared at 38.4°, while the intensities of (101), (002), and (040) peaks of cellulose were reduced. In conclusion, magnetron sputtering was used to deposit a superhydrophobic coating on wood without low surface free energy agents. Furthermore, this research provides new inspirations for the physical modification of wood and the construction of superhydrophobic coatings on wood.