Effect of nano-hydroxyapatite micromorphology on the properties and stability of superhydrophobic layers of wood

Superhydrophobic modification of wood surfaces can effectively limit the shrinkage and swelling of wood, thereby extending the service life of wood products. However, the practical application of superhydrophobic modification of wood surfaces is limited due to the poor stability of the superhydrophobic coating. The stability of the superhydrophobic coating is affected by the microscopic morphology of inorganic nanoparticles in the wood superhydrophobic layer. However, few research has systematically discussed this issue. In this paper, three types of hydroxyapatite nanomaterials (nanospheres, nanorods and nanowires), were used as raw materials for the superhydrophobic modification of wood surfaces by compounding with polydimethylsiloxane and spraying onto the wood surface. The effect of hydroxyapatite morphology on the stability of the superhydrophobic layer on wood was investigated through sandpaper wear, tape stripping, and chemical corrosion tests. The results demonstrate that hydroxyapatite nanospheres with smaller aspect ratios and sizes can efficiently penetrate the cellular walls and cavities of wood. As a result, the superhydrophobic layer prepared from these nanospheres exhibit better hydrophobicity and stability, and the obtained coatings can maintain superhydrophobicity after 15 cycles of sandpaper wearing and tape peeling. These findings provide a theoretical foundation for the development of high-performance and stable wood superhydrophobic coatings.