Laser-induced plasma-assisted ablation of sapphire microstructures and their wettability
Creating microstructures on sapphire surfaces is key to altering their wettability.The laser-in-duced plasma etching method offers distinct benefits for crafting these microstructures.This study exam-ines how laser fluence,the distance between the target and sapphire,and scanning speed impact the micro-grooves'morphology and geometry on sapphire surfaces using the laser-induced plasma-assisted ablation(LIPAA)technique,employing a controlled variable approach.Further,it explores how LIPAA's pro-cessing parameters affect the sapphire's surface contact angle through orthogonal testing.Results indicate that laser scan line spacing most significantly influences the surface contact angle,followed by the target-to-sapphire distance and laser fluence,with scanning speed having the minimal impact.At a laser fluence of 6.3 J/cm²,scan line spacing of 200 μm,target-to-sapphire distance of 150 μm,and scanning speed of 10 mm/s,the sapphire's surface contact angle reached 136°,demonstrating superior hydrophobicity.Con-versely,with a laser fluence of 7.4 J/cm²,scan line spacing of 50 μm,target-to-sapphire distance of 100μm,and scanning speed of 5 mm/s,the surface contact angle was 29°,indicating strong hydrophilicity,which remained stable over time.SEM observations revealed numerous nanoparticles on the sapphire mi-crostructures,which together influence the sapphire's wettability.