Conventional toolmaking is the backbone of the economy in many industrial sectors. Recently, this has reached its limits, as the necessary product functions on tools are becoming more complex and thus require new solu-tions. In the life science sector, increasing demands on the reproducibility and accuracy of lab-on-chip systems require new tools for the molding of polymer films with selectively functionalised surfaces. By applying local micro- and nano-structures to the molds, a multi-functionality of the films can be achieved, independent of the chemical composition. In particular, the wetting behavior of fluids on the functionlised surfaces can be con-trolled to selectively creating hydrophobic or hydrophilic surface conditions.

In this work, direct laser interference patterning is used to create periodic microstructures on tools for hot stamp-ing microfluidic films (steels 1.2083 and 1.4301) using nanosecond (ns) and picosecond (ps) pulsed laser sys-tems. The periodic structures have line and cross-like geometries with different spatial periods ranging from 4 μm to 8 μm. Aspect ratios of 0.3, 0.6, and 0.9 are achieved for all spatial periods. A total of 60 different surface topographies were fabricated and the wetting behavior of water was investigated over an interval of 30 days after fabrication. In addition, accompanying EDX measurements were performed to investigate the formation of car-bon and the degree of oxidation on the surfaces over time. The information obtained on surface topography, sur-face chemistry and wetting behavior will be stored in a database and used for predictive modeling of wetting be-havior in the future.