High‐Speed Surface Structuring of Polycarbonate Using Direct Laser Interference Patterning: Toward 1 m² min⁻¹ Fabrication Speed Barrier

Abstract

Periodic structures with micro-or sub-micrometer resolution can be used to improve the mechanical, biological, or optical properties of surfaces. Direct laser interference patterning combines high resolution (sub-micrometer feature sizes) with high fabrication speed. New processing heads for highspeed laser interference patterning of polycarbonate are introduced, which provide effective patterning speeds up to 0.9 m 2 min -1 . The surface topography of the processed polymer is analyzed by confocal microscopy and scanning electron microscopy. Focused ion beam is used to create cross-sections to determine the structuring mechanism. Finally, high-speed interference patterning is compared to conventional direct laser writing.

Direct laser interference patterning of transparent and colored polymer substrates: ablation, swelling, and the development of a simulation model

“…As previously demonstrated, adding a dopant to the polymer substrate can result not only in a change of the optical properties but also on a different structuring mechanism, i.e. creating swelled structures [22,23]. Thus, in a second set of experiments, PC substrates doped with a blue and gray dyes were used to quantitatively investigate the swelling process under DLIP for UV (266 nm) and IR (1053 nm) radiation.…”

Performance and Accuracy of the Shifted Laser Surface Texturing Method

“…It has advantages of the production of surface textures on a larger area simultaneously with the possibility of the production of very small surface features down to a 0.5 µm spatial period [40,41]. It has already achieved a processing speed of 0.9 m 2 /min for the surface structuring of plastics (foaming by a one-layer process) [42]. A disadvantage can be the limited variability of the surface texture-only the surface textures resulting from the interference can be produced.…”

Universal Micromachining Platform and Basic Technologies for the Manufacture and Marking of Microphysiological Systems

“…However, the size of the achievable structural parameters do not only depend on the spatial period of the interference pattern but on the kind of interaction between the laser light and the material (e.g., melting, evaporation, etc.). In the case of processing of polymer substrates, spatial periods even in the sub-micrometer range could be obtained due to the very short thermal diffusion lengths compared to metals, as it has been shown for polycarbonate [ 14 ], polyurethane [ 15 ], or poly (styrene-co-acrylonitrile) [ 16 ].…”

“…Due to the above mentioned characteristics, significantly shorter processing times are required for the DLIP-technology compared to DLW, especially to fabricate patterns with small feature sizes [ 14 ]. Depending on the desired spatial period, different optical setups can be used.…”