Effect of bionic microtexture geometry on the tribological performance of hydrophobic surfaces

This study intergrates experimental and theoretical approaches to explore the effect of bionic microtexture geometry on the tribological performance of hydrophobic surfaces. A theoretical model is established based on the extended Reynolds equation, and hydrophobic sandwich-like coatings with four types of bionic microtextures were fabricated using laser processing and electrohydrodynamic jet (EHDA) method. The mechanical durability and friction-wear characteristics of different samples were systematically investigated. The numerical results showed that the continuous dimple textured surface deposited with coatings (CTS-1) exhibited the largest slip velocity and the lowest friction. Sample CTS-2 exhibited best load bearing capacity with maximum surface pressure. Experimental results were consistent with the theoretical model, sample CTS-1 exhibited the lowest friction coefficient and CTS-2 had the best anti-wear performance. Compared with PS sample, the average friction coefficient of CTS-1 was reduced by 14.05 % and the wear rate of CTS-3 decreased by 19.66 %. This can be attributed to the improved slip effect of CTS-1 and higher load bearing capacity and lower cavitation of lubrication film on CTS-2. Furthermore, sample CTS-1 exhibited outstanding properties in durability tests and long-term sliding experiments, confirming the effective role of the continuous hexagonal dimple microtextures in protecting the hydrophobic nanocoatings during abrasion.