Roughness and wettability properties of plain and silica-coated copper surfaces textured with picosecond laser

Many recent studies have investigated the mechanism of wettability transition of laser-textured copper surfaces on different materials. Furthermore, several such studies have focused on approaches to accelerate wettability transition from hydrophilicity to hydrophobicity, such as temperature annealing and the use of chemical solutions. However, few researchers have focused on maintaining the initial hydrophilicity of laser-textured surfaces. This study presents a hybrid surface modification method involving chemical bath deposition and ultrafast laser. First, the selected copper substrates are modified using the sol-gel method through dip coating. Subsequently, the coated copper surfaces are irradiated with a picosecond laser. After laser texturing, bumpy structures are formed, and SiO₂ nanoparticles can be sintered on the surfaces. Thus, the original hydrophilicity can be maintained, and the surface roughness can be enhanced simultaneously. By using this hybrid modification method, a heterogeneous surface with high-precision patterns can be obtained. Moreover, the mechanism of wettability transition of laser-textured copper surfaces with different laser fluences is discussed using the Wenzel and Cassie Baxter wetting model by analyzing the chemical composition and surface morphology of the treated surfaces.