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Stainless steel (SST) is an important material for a variety of applications including construction, food, and medical. Highly hydrophobic wetting properties enhance the surface properties of SST to support processes such as self‐cleaning. However, applications also require long‐term stability of such properties against chemical and mechanical influences from the environment or technical processes. Therefore, the reduction of highly hydrophobicity of chemically modified, laser‐textured SST surfaces is investigated in relation to abrasive wear using hierarchical structures, micro‐/nanotextured surface, and support structures that shield the highly hydrophobic pattern. Surface textures comprising ridges, grooves (size: 50–500 μm; depth: up to 100 μm), and a nanostructured grooves bottom are machined by infrared ultrashort pulse laser ablation into SST and are subsequently chemically modified by a self‐assembled monolayer of a fluorinated, phosphonic acid‐modified alkane. Abrasive wear tests of these surfaces show decreasing water contact angles with increasing wear of the modified surface of the support structures. However, there is good stability of the highly hydrophobic properties due to the protection of modified areas at the groove bottom. The proposed wetting model for such designed functionalized laser textures shows possibilities for further optimization of such robust highly hydrophobic surfaces and adaptation to specific applications. [ABSTRACT FROM AUTHOR]

The fabrication of plasmonic 3D microstructures is still a challenge. In this study, the fabrication of gold‐nanoparticle (Au‐NP)‐filled acrylate‐based micron‐scale cuboids forming plasmonic 3D particles is investigated. UV curable acrylate is mixed with HAuCl4 and spin‐coated onto a fused silica wafer. UV light and heat treatment of the layer result in polymerization of the acrylate and formation of Au‐NPs with a plasmonic resonance ranging from 535 to 550 nm. The plasmonic resonance wavelength decreases slightly with increasing UV dose. The resonance wavelength can be shifted by a subsequent annealing process. The decreasing resonance wavelength with increasing annealing temperature is discussed as a result of the increasing Au‐NPs. The size and the distribution of the resulting gold particles in the acrylate matrix is investigated by transmission electron microscopy. The Au‐NPs‐filled acrylate layer is laser structured using a UV‐femtosecond laser, which allows the fabrication of adjustable micro‐cuboids with edge lengths down to 15 μm. The laser‐cut micro‐cuboids are transferred into isopropanol and the plasmonic properties of the structures in the liquid are successfully demonstrated. The presented concept allows easy and large‐scale fabrication of plasmonic microstructures with independently adjustable plasmonic properties and microstructural size and shape. [ABSTRACT FROM AUTHOR]

The structuring of thermal-sensitive functional layers by laser patterning methods remains a challenge. The shock-wave-induced thin-film delamination (SWIFD) process is a non-thermal process of mechanically-induced film removal where the process exhibits an extraordinary application potential. Due to the spatial separation of laser ablation that is performed at the rear side of the substrate and the shock-wave-induced thin film delamination at the substrate's film side the thermal impact to the thin films is excluded. The SWIFD process for CIGS solar cells on polyimide substrates was studied for dependence on externally applied tension forces F. The resulting SWIFD patterns are imaged by scanning electron microscopy (SEM) to analyze the geometrical shape and the surface morphology. A reduction of the CIGS delamination threshold fluence Φth as well as a slight increase of the delaminated area A with increasing tension forces F is found. Like previous results, the area A increases with growing laser fluence and number of laser pulses and the Φth decreases with increasing number of laser pulses. The non-thermal nature of the SWIFD process, enabling a film-selective delamination of the CIGS layer (including the front contact) without damaging the Mo back contact, is also shown. [ABSTRACT FROM AUTHOR]

Three-dimensional micro- and nanostructuring of metal surfaces is requested due to the ongoing miniaturization and is therefore of great interest for microelectromechanical systems (MEMS), micro- optics, and precision machining. One promising fabrication method for low-cost, high-quality micro- and nanostructured metal surfaces is laser microembossing. Recent experimental results of laser embossing of submicron structures are presented to discuss the processes and characteristics of laser micro-embossing. Basically, laser embossing shows almost no modification caused by thermal effects of the laser pulses. Therefore, almost no burr, recast droplets, or near-surface material modifications have been found at the embossed structures. The elastoplastic deformation at incomplete submicron pattern embossing is probably the reason for the differences between the replicated pattern and the master structures. Unintended patterns like scratches and satellite patterns may occur in the case of multi-pulse laser embossing without carefully fixing the sample and master positions. [ABSTRACT FROM AUTHOR]