Long-Lasting Hydrophilicity of Al₂O₃ Surfaces via Femtosecond Laser Microprocessing

We explore the wettability modulation induced on alumina (Al₂O₃) targets by femtosecond laser texturing to demonstrate a stable and durable hydrophilic character of the surface. Specifically, we identify a suitable operational regime to tailor micro-nanostructures onto Al₂O₃ plates and accurately assess the ablation threshold in our experimental conditions. A periodic geometry with triangular patterns of various groove depths was optimized for establishing a long-term wetting response. The latter was monitored on daily basis over a time interval of six-weeks by collecting contact angle measurements of samples with and without a post-process thermal annealing, here adopted to stabilize the surface wettability soon after the We explore the wettability modulation induced on alumina (Al₂O₃) targets by femtosecond laser texturing to demonstrate a stable and durable hydrophilic character of the surface. Specifically, we identify a suitable operational regime to tailor micro-nanostructures onto Al₂O₃ plates and accurately assess the ablation threshold in our experimental conditions. A periodic geometry with triangular patterns of various groove depths was optimized for establishing a long-term wetting response. The latter was monitored on daily basis over a time interval of six-weeks by collecting contact angle measurements of samples with and without a post-process thermal annealing, here adopted to stabilize the surface wettability soon after the laser treatment. Results show that deeper grooves significantly enhance and maintain the hydrophilic character, particularly in samples without post-process thermal annealing, where super-hydrophilicity is demonstrated to persist throughout the entire time under test. These findings disclose the potential for an effective fine-tuning of the alumina wettability, thus opening to specific applications requiring long-term control of surface-liquid interactions, such as biomedical implants, orthopedic and dental prostheses. laser treatment. Results show that deeper grooves significantly enhance and maintain the hydrophilic character, particularly in samples without post-process thermal annealing, where super-hydrophilicity is demonstrated to persist throughout the entire time under test. These findings disclose the potential for an effective fine-tuning of the alumina wettability, thus opening to specific applications requiring long-term control of surface-liquid interactions, such as biomedical implants, orthopedic and dental prostheses.