Anisotropic wettability induced by femtosecond laser ablation

Abstract

Laser ablation has been utilized for locally and selectively modifying the surface wettability of materials in situ and enabling on-demand microfabrication. The anisotropic wettability has been observed on chemical and/or topographical patterns, such as an array of laser-inscribed strips with spacings, created on surfaces during the fabrication process. Herein, the effectiveness of the femtosecond laser ablation is evaluated in selectively modifying surface wettability. The areas processed by laser ablation exhibit anisotropic wetting behavior, even after the laser strips are overlapped. The laser-induced anisotropic surface wettability is present in space governed by laser scanning speed, scan/strip overlap, laser fluence, scan repetition, and bidirectional scanning angle. Moreover, the femtosecond laser ablation process is optimized to enhance the conventional laser inscription, leading to a modified and consistent methodology to achieve cost-effective fabrication. Herein, an approach for locally and selectively modifying surface wettability of materials in situ induced by femtosecond laser ablation is described. The laser-induced anisotropic surface wettability is found to appear in space governed by laser scanning speed, scan/strip overlap, laser fluence, scan repetition, and bidirectional scanning angle.