Porous membranes with special wetting properties have attracted great interest due to their various functions and wide applications, including water filtration, selective oil/water separation and oil skimming. Special wetting properties such as superhydrophobicity can be achieved by controlling the surface chemistry as well as the surface topography of a substrate. Three-dimensional (3D) printing is a promising method for the fast and easy generation of various structures. The most common method for 3D printing of superhydrophobic materials is a two-step fabrication process: 3D printing of user-defined topographies, such as surface structures or bulk porosity, followed by a chemical post-processing with low-surface energy chemicals such as fluorinated silanes. Another common method is using a hydrophobic polymer ink to print intricate surface structures. However, the resolution of most common printers is not sufficient to produce nano-/microstructured textures, moreover, the resulting delicate surface micro- or nanostructures are very prone to abrasion. Herein, we report a simple approach for 3D printing of superhydrophobic micro-/nanoporous membranes in a single step, combining the required topography and chemistry. The bulk porosity of this material, which we term “Fluoropor”, makes it insensitive to abrasion. To achieve this, a photocurable fluorinated resin is mixed with a porogen mixture and 3D printed using a stereolithography (SLA) printing process. This way, micro-/nanoporous membranes with superhydrophobic properties with static contact angles of 164° are fabricated. The pore size of the membranes can be adjusted from 30 nm to 300 nm by only changing the porogen ratio in the mixture. We show the applicability of the printed membranes for oil/water separation and the formation of Salvinia layers which are of great interest for drag reduction in maritime transportation and fouling prevention.

The customized processing of polymer materials in the microscale by high‐resolution 3D printing provides an easy access to advanced applications in the fields of optics, microfluidics, tissue engineering, and life science. However, the 3D printing of enclosed structures in the scale of tens of microns such as closed microfluidic channels remains a challenge as channel structures often are clogged by residual cured resin. Dual‐curing systems based on off‐stoichiometric thiol‐ene and thiol‐ene/epoxy chemistry are well‐known for adhesive‐free bonding in the fabrication of cast or injection molded microfluidic devices. Herein, the first high‐resolution stereolithography 3D printing of a dual‐curing thiol‐ene/epoxy system in the microscale for the fabrication of customized microfluidic devices is presented. In the first curing step, by high‐resolution 3D printing open microfluidic structures are produced. Consecutively, the microchannels are sealed by adhesive‐free dry bonding upon thermal initiation, producing well‐controlled structures with channel sizes down to 80 µm. Before bonding, the intermediate material allows for tailored surface modification with biotin, which allows for consecutive immobilization of various biomolecules. A DNA‐bioassay with specific patterning is shown in the sealed chip. The presented work paves the way toward the fabrication of customized microfluidic devices for a large range of specific bioassays.

Platinum (Pt) is an interesting material for many applications due to its high chemical resilience, outstanding catalytic activity, high electrical conductivity, and high melting point. However, microstructuring and especially 3D microstructuring of platinum is a complex process, based on expensive and specialized equipment often suffering from very slow processing speeds. In this work, organic–inorganic photoresins, which can be structured using direct optical lithography as well as two‐photon lithography (TPL) with submicrometer resolution and high‐throughput is presented. The printed structures are subsequently converted to high‐purity platinum using thermal debinding of the binder and reduction of the salt. With this technique, complex 3D structures with a 3D resolution of 300 nm were fabricated. At a layer thickness of 35 nm, the patterns reach a high conductivity of 67% compared to bulk platinum. Microheaters, thermocouple sensors as well as a Lab‐on‐a‐Chip system are presented as exemplary applications. This technology will enable a broad range of application from electronics, sensing and heating elements to 3D photonics and metamaterials.

Microstructured molds are essential for fabricating various components ranging from precision optics and microstructured surfaces to microfluidics. However, conventional fabrication technology such as photolithography requires expensive equipment and a large number of processing steps. Here, we report a facile method to fabricate micromolds based on a reusable photoresponsive hydrogel: Uniform micropatterns are engraved into the hydrogel surface using photo masks under UV irradiation within a few minutes. Patterns are replicated using polydimethylsiloxane with minimum feature size of 40 μm and smoothness of R_q ~ 3.4 nm. After replication, the patterns can be fully erased by light thus allowing for reuse as a new mold without notable loss in performance. Utilizing greyscale lithography, patterns with different height levels can be produced within the same exposure step. We demonstrate the versatility of this method by fabricating diffractive optical elements devices and a microlens array and microfluidic device with 100 µm wide channels.

Tomographic volumetric additive manufacturing support-free 3D printing has significantly faster print speed than traditional vat photopolymerization and material extrusion techniques. At the same time, tomographic volumetric additive manufacturing allows the embedding of external objects in the print volume before the print to produce complex multi part assemblies by so-called overprinting. As tomographic volumetric additive manufacturing increases its popularity, more and more of its limitations with regards to available materials are removed, and printing with acrylates, ceramics and glasses has been shown. However, creating multi material parts without resorting to overprinting is still challenging. Here, multi-material tomographic volumetric additive manufacturing printing is presented by combining tomographic volumetric additive manufacturing and Embedded 3D printing: photopolymerizable support baths are used to deposit inks in defined shapes allowing the consecutive definition and volumetric printing of multi-material structures via tomographic volumetric additive manufacturing. We show the fabrication of several multi-material structures with arbitrarily positioned materials, as well as chips with microchannels having diameters lower than 120 µm.

Superhydrophobic coatings are widely applicable, e.g., as self‐cleaning surfaces or water–oil separation membranes, yet their wider usage is impeded due to costs of fabrication, size, or substrate limitation. Spray‐coating is a versatile coating procedures and might offer a good solution for the fabrication of these superhydrophobic coatings, due to the fact that coatings can be fabricated on various materials in a simple, fast, and inexpensive manner. Most procedures rely on hybrid coatings of hydrophobized nanoparticles and a polymeric matrix, which have several drawbacks including the easy loss of nanoparticles and difficult waste handling. Here, the fabrication of the superhydrophobic material, called Fluoropor, for the first time, by spray‐coating on various substrates including metals, tissues, concrete, and glass is presented. It is fabricated by spray‐coating a mixture of a highly fluorinated monomer blended with porogens followed by photopolymerization. The superhydrophobicity of the material relies on the porous structure on the micro‐/nanoscale across the bulk material and does not require any nanoparticles. Excellent self‐cleaning ability of these coatings, resistance against thermal and abrasive impact, and their application as oil–water separation membranes are shown. This versatile applicability is highly promising for real‐world application as self‐cleaning coatings or oil–water separating membranes.