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Effective and reliable interconnections are crucial for microfluidics to connect with the macro world. Current microfluidic interfaces are still bulky, expensive, or with issues of clogging and material limitation. In this study, a novel ultraviolet (UV)-assisted coaxial three-dimensional (3D) printing approach was proposed to fabricate hollow microfluidic connectors with advantages of rapid prototyping, fixture-free, and materials compatible. An assembled coaxial nozzle was designed to enable co-flow extrusion, where the inner flow (water) served as the sacrificial layer and the outer flow (adhesive) was cured for shell formation. Furthermore, a converged UV-LED light source was attached to the coaxial nozzle for UV curing of adhesives. UV rheological characterizations were performed to study the UV curing kinematics, and the gelation time was employed to describe the state transition behaviors of UV curable adhesives used in the study. To explore requirements for successful hollow connectors direct printing, processing criteria such as co-flow regime and pre-cure time were investigated. The hollow connectors with an inner channel diameter of ~150 μ m and a height of 5 mm were successfully printed on polymethyl methacrylate (PMMA) and glass substrate. The integration feasibility of the proposed method was also demonstrated by the presented microfluidic device with printed hollow connectors.

It is of pivotal significance to probe highly efficient, cost-effective and low-cost catalysts for hydrogen evolution reaction. Herein, closely packed carbon-encapsulated CuO/Cu2O heterohedron with heterojunction structure is reported that combines...

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It is of importance to explore a bifunctional electrocatalyst for water splitting. Herein, unique ZnCo2O4-CoOOH heterostructured ultrathin nanosheets on Ni Foam are reported that combines a two-step hydrothermal method. This...

A novel fluorescent probe CN3, containing 1,8‐naphthalimide and picolinate units, was synthesized, and its structure was characterized by 1H nuclear magnetic resonance spectroscopy (H NMR), 13C nuclear magnetic resonance spectroscopy (C NMR), and mass spectroscopy techniques. The detection property of CN3 toward copper ions (Cu2+) has been investigated in ethanol–HEPES buffer (v/v = 1/1, pH = 7.40) solution by UV–Vis absorption and fluorescence emission spectra. The results showed that CN3 had a highly selective and sensitive fluorescence quenching response to Cu2+, which was attributed to the generation of weak fluorescent N‐ethyl‐4‐hydroxyphenyl‐1,8‐ naphthalimide (compound 2) in polar ethanol–HEPES buffer (v/v = 1/1, pH = 7.40) via selective hydrolysis reaction. The detection of CN3 for Cu2+ was not influenced in the presence of other competing metal ions, and the limit of detection was as low as 50.0 nM. Therefore, the color of CN3 changed from colorless to yellowish when the Cu2+ was added. Furthermore, the fluorescent probe CN3 was utilized to detect Cu2+ in real water samples with fine performance.

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