Direct Laser Interference Patterning of Nickel Foils for Enhanced Bubble Nucleation in Oxygen-Oversaturated Environment

This study investigates the functionalization of high-purity nickel (Ni) surfaces for the oxygen bubble nucleation via direct laser interference patterning (DLIP). Line-like surface structures with spatial periods of 6.0, 15.0, and 30.0 µm and depths of 1 and 5 µm are fabricated using a picosecond pulsed laser source. The structuring process involves material ablation, redeposition, and the formation of laser-induced periodic surface structures (LIPSS), resulting in hierarchical surface textures. The influence of topographical parameters resulting from the DLIP treatment on the oxygen bubble nucleation dynamics is examined in a specifically prepared oxygen-oversaturated aqueous solution. The periodic patterns having a spatial period of 6.0 µm and a structure depth of 5 µm show the strongest surface area enlargement (S<inf>dr</inf> = 117%), with a 278-fold increase in bubble nucleation density, and significantly smaller average bubble sizes (∼140 µm) compared to the nonstructured reference (∼340 µm). Furthermore, enhanced coalescence and faster bubble detachment suggest improved gas release characteristics. These findings underscore the potential of DLIP-based surface structuring to optimize performance for gas evolution applications.