Control of the wetting properties of an AISI 316L stainless steel surface by femtosecond laser-induced surface modification

A simple and effective method without vacuum to control the wetting properties of AISI 316L stainless steel using femtosecond laser pulses at high repetition rate has been developed. Both hydrophilic and hydrophobic surfaces were formed by creating micro-conical structures on the surface with femtosecond laser irradiation in air. The scan speed was found to be an effective parameter in controlling micro-cone morphology, size and number densities and contact angles during surface wettability experiments. It was found during surface wettability experiments that the contact angle of water varied from 0◦ (superhydrophilic) to 113◦ on laser micro-cone textured surfaces depending on processing conditions. Additionally, a superhydrophobic AISI 316L stainless steel surface was created (contact angle ∼150◦) with a functionalized silane coating on already hydrophobic surface geometry. (Some figures may appear in colour only in the online journal)