Hierarchical structures for functional surfaces: fundamentals, modeling, and functional integration

Hierarchically structured functional surfaces on metallic substrates offer precise control over wettability and fluid transport, enabling advanced microfluidic applications. This talk presents key insights into their fabrication via ultra-short pulsed (USP) laser processing, highlighting the interplay between surface topography, chemistry, and processing parameters. A multiple regression model based on contact angle measurements and XPS data quantitatively links surface chemistry to wetting behavior. Long-term stability studies reveal correlations between chemical aging and wettability changes. These results are applied and demonstrated using the example of the functionalization and subsequent USP microwelding of 20 µm stainless steel foils (1.4301). The results support novel design concepts for internally structured pipelines and controllable wetting architectures, enabling active fluid management without additional substrates.