High-density, highly sensitive sensor array of spiky carbon nanospheres for strain field mapping.

While accurate mapping of strain distribution is crucial for assessing stress concentration and estimating fatigue life in engineering applications, conventional strain sensor arrays face a great challenge in balancing sensitivity and sensing density for effective strain mapping. In this study, we present a Fowler-Nordheim tunneling effect of monodispersed spiky carbon nanosphere array on polydimethylsiloxane as strain sensor arrays to achieve a sensitivity up to 70,000, a sensing density of 100 pixel cm-2, and logarithmic linearity over 99% within a wide strain range of 0% to 60%. The highly ordered assembly of spiky carbon nanospheres in each unit also ensures high inter-unit consistency (standard deviation ≤3.82%). Furthermore, this sensor array can conformally cover diverse surfaces, enabling accurate acquisition of strain distributions. The sensing array offers a convenient approach for mapping strain fields in various applications such as flexible electronics, soft robotics, biomechanics, and structure health monitoring.

Amorphous MnO2 Lamellae Encapsulated Covalent Triazine Polymer-Derived Multi-Heteroatoms-Doped Carbon for ORR/OER Bifunctional Electrocatalysis.

The intelligent construction of non-noble metal materials that exhibit reversible oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) with bifunctional electrocatalytic performance is greatly coveted in the realm of zinc-air batteries (ZABs). Herein, a crafted structure-amorphous MnO2 lamellae encapsulated covalent triazine polymer-derived N, S, P co-doped carbon sphere (A-MnO2/NSPC) is designed using a self-doped pyrolysis coupled with an in situ encapsulation strategy. The customized A-MnO2/NSPC-2 demonstrates a superior bifunctional electrocatalytic performance, confirmed by a small ΔE index of 0.64 V for ORR/OER. Experimental investigations, along with density functional theory calculations validate that predesigned amorphous MnO2 surface defects and abundant heteroatom catalytic active sites collectively enhance the oxygen electrocatalytic performance. Impressively, the A-MnO2/NSPC-based rechargeable liquid ZABs show a large open-circuit potential of 1.54 V, an ultrahigh peak power density of 181 mW cm-2, an enormous capacity of 816 mAh g-1, and a remarkable stability for more than 1720 discharging/charging cycles. Additionally, the assembled flexible all-solid-state ZABs also demonstrate outstanding cycle stability, surpassing 140 discharging/charging cycles. Therefore, this highly operable synthetic strategy offers substantial understanding in the development of magnificent bifunctional electrocatalysts for various sustainable energy conversions and beyond.

Skin-Integrated Electrodes Based on Room-Temperature Curable, Highly Conductive Silver/Polydimethylsiloxane Composites.

The quality of electrophysiological (EP) signals heavily relies on the electrode's contact with the skin. However, motion or exposure to water can easily destabilize this connection. In contrast to traditional methods of attaching electrodes to the skin surface, this study introduces a skin-integration strategy inspired by the skin's intergrown structure. A highly conductive and room-temperature curable composite composed of silver microflakes and polydimethylsiloxane (Ag/PDMS) is applied to the skin. Before curing, the PDMS oil partially diffuse into the stratum corneum (SC) layer of the skin. Upon curing, the composite solidifies into an electrode that seamlessly integrated with the skin, resembling a natural extension. This skin-integration strategy offers several advantages. It minimizes motion artifacts resulting from relative electrode-skin displacement, significantly reduces interface impedance (67% of commercial Ag/AgCl gel electrodes at 100 Hz) and withstands water flushes due to its hydrophobic nature. These advantages pave the way for promising advancements in EP signal recording, particularly during motion and underwater conditions.

High-entropy oxides as photocatalysts for organic conversion.

A strategy involving organic photocatalytic conversion using hydrothermal synthesis of high-entropy oxide (HEO) (CoCuZnMnNa)Ox nanoparticles was developed. Under mild conditions, HEO nanoparticles were driven by visible light to achieve ideal yields and selectivity in sulfide oxidative coupling reactions and benzimidazole cyclization reactions, with a wide substrate range. This study is expected to contribute to the use of high-entropy oxides in organic photocatalysis.

Facile fabrication, morphology control, and modification of polymeric yolk-shell microspheres.

The fabrication and functionalization of polymeric yolk-shell microspheres (YSMs), possessing a hollow shell and a movable core, is interesting but challenging in materials science. Here we report the facile fabrication, morphology control, and fluorescent modification of polymeric YSMs, which have a spherical core of poly(vinylidene fluoride) (PVDF) and a hollow shell of poly(styrene-co-glycidyl methacrylate). First, flower-like microspheres with core-shell structures are synthesized via seeded surface nucleation in an emulsion polymerization of styrene, glycidyl methacrylate, and divinylbenzene by using PVDF microparticles as seeds. Both the feed ratio and the polymerization time are considered to manipulate the core-shell structures of the composite microparticles, which obviously influences the morphology of the YSMs obtained from the subsequent treatment of solvent etching to remove the seed. The hollow volume of the polymeric YSMs is easily adjusted by changing the etching time at different temperatures. Meanwhile, we realized three-dimensionally confined crystallization of PVDF in different morphologies of YSMs. Furthermore, YSMs with the same or different functional groups, inside and outside of the hollow shell, respectively, are chemically modified by the reaction of glycidyl groups on the shell with 2,2'-(ethylenedioxy) bis-ethylamine. Thus, strong fluorescence of the YSMs is observed by subsequent labeling with functional fluorescent groups.