Tuning water wetting angle of a steel surface via nanosecond laser ablative nano/microtexturing for chemical and biomedical microfluidic applications

Broad tunability of water wetting angle on an AISI 304 steel surface was demonstrated by 1064 nm, 100 ns laser ablative nano- and micro-texturing in the air at different incident fluences. Surface textures, supporting higher and lower water wetting angles, were produced at the increasing above-threshold fluence, visualized by optical microscopy, and characterized regarding their water wetting. The different surface relief textures produced exhibit a drastic fluence-dependent drop (≈60°) of water contact angles until the superhydrophilic ones are produced, enabling the design and fabrication of surface microfluidic devices for chemical and biomedical applications.