Mimic Lotus Surface with Super-Hydrophobicity Prepared through Surface-Molten Particle Deposition by flame spraying Assisted with Modification

摘要

In the nature, the leaf surface of many plants or body surface of some animals exhibit water-repellent, or hydrophobic, a property to get rid of the annoyance of being wet. The most famous one is the lotus leaf surface with a contact angle (CA) of water of about 162° and a sliding angle (SA) of about 2°. The super-hydrophobicity endows the lotus leaf the ability of keeping dry and self-clean in the dirty pool. Inspired by the lotus effect, artificial super-hydrophobic surfaces have been created and applied in the industrial area and daily life. Thermal spraying is widely used to efficiently to prepare coatings with various properties. Previous studies showed that semi-molten, even limited surface-molten particles generated by flame spraying can be well deposited on a substrate. The 'stand-up' solid core greatly alters the roughness of a flat substrate surface. Furthermore, during flame spraying of high-density Mo particles, a secondary structure is formed through the oxidization of metal Mo or reduction of Mo oxides on the Mo particle surface. The fabrication of a hierarchical structure of surface-molten Mo particles over the substrate could be expected. Therefore, in this study, surface-molten Mo particles were deposited by flame spraying to construct the hierarchical structure and FAS was used to modify the structure to fabricate an artificial lotus surface. The influences of annealing, FAS treatment and coverage ratio of Mo particles over the substrate surface on the wettability of water drop were investigated.