Fabrication of a Composite Groove Array Surface with Gradient Wettability Which Delivers Enhanced Lubrication Performance

A novel composite groove array surface was fabricated using femtosecond laser ablation technology to enhance self-replenishment capability. Initially, the driving efficiency of droplets on the composite groove array surface was tested using a high-speed droplet transportation system, characterizing the effect of this surface on lubricant backflow characteristics. Simultaneously, measurement of lubricating film thickness was utilized to explore the lubrication enhancement effect of the composite groove array surface on oil film formation under reciprocating motion. The multidimensional gradient wettability, engineered through the composite groove array surface, demonstrated excellent efficiency in lubricant replenishment within the lubrication track. Oil droplet transportation testing demonstrated that the composite groove array surface, which induced gradient wettability at the boundary, attained a maximum driving speed of 123.5 mm/s. This innovative design significantly reduced the barriers associated with lubricant backflow, particularly those induced by cavitation expansion during high-frequency reciprocating motion. Furthermore, the results demonstrated that the film-forming capabilities of this composite groove array surface were enhanced, thereby optimizing the overall lubrication performance.