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.

High overpotentials, particularly an issue of common anode materials, hamper the process of water electrolysis for clean energy generation. Thanks to immense research efforts, up-to-date oxygen evolution electrocatalysts based on earth-abundant elements work efficiently and stably in neutral and alkaline regimes. However, non-noble metal-based anode materials that can withstand low pH regimes are considered to be an indispensable prerequisite for the water splitting to succeed in the future. All oxygen-evolving electrodes working durably and actively in acids contain Ir at least as an additive. Due to their scarcity and high acquisition costs, noble elements like Pt, Ru and Ir need to be replaced by earth-abundant elements. We have evaluated a Ni-containing stainless steel for use as an oxygen-forming electrode in diluted H₂SO₄. Unmodified Ni42 steel showed a significant weight loss after long-term OER polarization experiments. Moreover, a substantial loss of the OER performance of the untreated steel specimen seen in linear sweep voltammetry measurements turned out to be a serious issue. However, upon anodization in LiOH, Ni42 alloy was rendered in OER electrocatalysts that exhibit, under optimized synthesis conditions, stable overpotentials down to 445 mV for a current density of 10 mA cm⁻² at pH 0. Even more importantly, the resulting material has been proven to be robust upon long-term usage (weight loss: 20 μg mm⁻² after 50 ks of chronopotentiometry at pH 1) towards OER in H₂SO₄. Our results suggest that electrochemical oxidation of Ni42 steel in LiOH (sample Ni42Li205) results in the formation of a metal oxide-containing outer zone that supports solution route-based oxygen evolution in the acidic regime accompanied by good stability of the catalyst.

A novel oxygen evolution reaction (OER) catalyst (3 D S235‐P steel) based on a steel S235 substrate was successfully prepared by facile one‐step surface modification. The standard carbon‐manganese steel was phosphorized superficially, which led to the formation of a unique 3 D interconnected nanoporous surface with a high specific area that facilitated the electrocatalytically initiated oxygen evolution reaction. The prepared 3 D S235‐P steel exhibited enhanced electrocatalytic OER activities in the alkaline regime, as confirmed by a low overpotential (326 mV at a 10 mA cm⁻²) and a small Tafel slope of 68.7 mV dec⁻¹. Moreover, the catalyst was found to be stable under long‐term usage conditions, functioning as an oxygen‐evolving electrode at pH 13, as evidenced by the sufficient charge‐to‐oxygen conversion rate (faradaic efficiency: 82.11 and 88.34 % at 10 and 5 mA cm⁻², respectively). In addition, it turned out that the chosen surface modification delivered steel S235 as an OER electrocatalyst that was stable under neutral pH conditions. Our investigation revealed that the high catalytic activities likely stemmed from the generated Fe/(Mn) hydroxide/oxohydroxides generated during the OER process. Phosphorization treatment therefore not only is an efficient way to optimize the electrocatalytic performance of standard carbon‐manganese steel but also enables for the development of low‐costing and abundant steels in the field of energy conversion.

Polymeric shape-memory elastomers can recover to a permeant shape from any programmed deformation under external stimuli. They are mostly cross-linked polymeric materials and can be shaped by three-dimensional (3D) printing. However, 3D printed shape-memory polymers so far only exhibit elasticity above their transition temperature, which results in their programmed shape being inelastic or brittle at lower temperatures. To date, 3D printed shape-memory elastomers with elasticity both below and above their transition temperature remain an elusive goal, which limits the application of shape-memory materials as elastic materials at low temperatures. In this paper, we printed, for the first time, a custom-developed shape-memory elastomer based on polyethylene glycol using digital light processing, which possesses elasticity and stretchability in a wide temperature range, below and above the transition temperature. Young's modulus in these two states can vary significantly, with a difference of up to 2 orders of magnitude. This marked difference in Young's modulus imparts excellent shape-memory properties to the material. The difference in Young's modulus at different temperatures allows for the programming of the pneumatic actuators by heating and softening specific areas. Consequently, a single actuator can exhibit distinct movement modes based on the programming process it undergoes.