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Elasto-inertial focusing in viscoelastic fluids has attracted increasing interest in recent years due to its potential applications in particle counting and sorting. However, current investigations of the elasto-inertial focusing mechanisms have mainly been focused on simple straight channels with little attention being paid to curved channels. Herein, we experimentally explore the elasto-inertial focusing behaviors of particles in spiral microfluidic channels over a wide range of flow rates, channel aspect ratios and channel radii. As compared with those observed in inertial microfluidics without viscoelasticity, the particle focusing pattern in our spiral elasto-inertial microfluidic system appears in a more interesting manner due to the complex coupling of elasticity, inertia and Dean flow effects. On the basis of the obtained data, the underlying mechanics and force competition behind the focusing behaviors are analyzed. In addition, for the first time, we propose a six-stage process model illustrating the particle focusing process in Dean-coupled elasto-inertial flows with increasing flow rate. It is interesting to find that the Dean drag force makes a significant contribution to particle focusing only at high flow rates and finally shifts the particle focusing positions into the outer channel region. Through carefully balancing the forces acting on particles, single-line 3D focusing can also be achieved at a throughput level of ∼100 μl min(-1), which is much higher than those in most existing studies. We envision that this improved understanding of the particle focusing mechanisms would provide helpful insights into the design and operation of spiral elasto-inertial microfluidic systems.

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Battery safety is critical for many applications including portable electronics, hybrid and electric vehicles, and grid storage. For lithium ion batteries, the conventional polymer based separator is unstable at 120 °C and above. In this research, we have developed a pure aluminum oxide nanowire based separator; this separator does not contain any polymer additives or binders; additionally, it is a bendable ceramic. The physical and electrochemical properties of the separator are investigated. The separator has a pore size of about 100 nm, and it shows excellent electrochemical properties under both room and high temperatures. At room temperature, the ceramic separator shows a higher rate capability compared to the conventional Celgard 2500 separator and life cycle performance does not show any degradation. At 120 °C, the cell with the ceramic separator showed a much better cycle performance than the conventional Celgard 2500 separator. Therefore, we believe that this research is really an exciting scientific breakthrough for ceramic separators and lithium ion batteries and could be potentially used in the next generation lithium ion batteries requiring high safety and reliability.

The response to glucose, pH and temperature, high drug loading capacity, self-regulated drug delivery and degradation in vivo are simultaneously probable by applying a multifunctional microgel under a rational design in a colloid chemistry method. Such multifunctional microgels are fabricated with N-isopropylacrylamide (NIPAAm), (2-dimethylamino)ethyl methacrylate (DMAEMA) and 3-acrylamidephenylboronic acid (AAPBA) through a precipitation emulsion method and cross-linked by reductive degradable N,N'-bis(arcyloyl)cystamine (BAC). This novel kind of microgel with a narrow size distribution (∼250 nm) is suitable for diabetes because it can adapt to the surrounding medium of different glucose concentrations over a clinically relevant range (0-20 mM), control the release of preloaded insulin and is highly stable under physiological conditions (pH 7.4, 0.15 M NaCl, 37 °C). When synthesized multifunctional microgels regulate drug delivery, they gradually degrade as time passes and, as a result, show enhanced biocompatibility. This exhibits a new proof-of-concept for diabetes treatment that takes advantage of the properties of each building block from a multifunctional micro-object. These highly stable and versatile multifunctional microgels have the potential to be used for self-regulated therapy and monitoring of the response to treatment, or even simultaneous diagnosis as nanobiosensors.

Rational design and preparation of single‐atom catalysts provide a promising strategy to significantly improve the electrocatalytic activity for water splitting. In particular, single atoms anchored at cationic vacancies can enhance the stability of the catalysts and improve reaction kinetics. In this work, Pt single atoms are loaded at layered α‐Ni2/3Fe1/3(OH)2 by oxidizing Fe2+ with H2PtCl6, and specifically, Pt atoms are anchored at in situ generated iron cationic vacancies during the process, resulting in stabilized Pt single atoms in the surface of α‐Ni2/3Fe1/3(OH)2 with the maximum loading of ≈6.15 wt%. The Pt single atoms not only act as active sites for hydrogen evolution reaction but also regulate the electronic structure of NiFe hydroxides and activate Ni atoms adjacent to Pt for oxygen evolution reaction. Therefore, the water‐splitting electrolyzer assembled with such a bifunctional catalyst shows a smaller overpotential than that with RuO2 and 20 wt% Pt/C catalysts as the anode and cathode, respectively, and efficient solar‐to‐hydrogen conversion. The results demonstrate the practical application of single‐atom Pt catalysts with low cost, large loading, and facile preparation route.

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