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Aqueous flow batteries (AFBs) are among the most promising electrochemical energy storage solutions for the massive-scale adoption of renewable electricity because of decoupled energy and power, design flexibility, improved safety and low cost. The development of high-voltage AFB is, however, limited by the lack of stable anolytes that have low redox potential. Here we report Eu-based anolytes for high-voltage pH-neutral AFB applications. Eu3+ has a reduction potential of −0.39 V vs. SHE, which can be dramatically lowered when forming stable complex with inexpensive organic chelates. A typical complex, EuDTPA, features a low redox potential of −1.09 V vs. SHE, fast redox kinetics, and a high water solubility of 1.5 M. When paired with ferrocyanide, the battery had an open-circuit voltage of 1.56 V and demonstrated stable cell cycling performance, including a capacity retention rate of 99.997% per cycle over 500 cycles at 40 mA cm−2, a current efficiency of >99.9%, and an energy efficiency of >83.3%. A high concentration anolyte at 1.5 M exhibited a volumetric capacity of 40.2 Ah L−1, which is one of the highest known for pH-neutral AFBs, promising a potent solution for the grid-scale storage of renewable electricity.

Phototherapy holds great promise for disease treatment; however, traditional “always-on” photoagents have been restricted to clinical translation due to their nonspecific response and side effects on normal tissues. Here, we show a tumor microenvironment activated photothermal and photoacoustic agent as an activatable prodrug and probe that allows precise cancer diagnosis and treatment. Such an in situ revitalized therapeutic and contrast agent is achieved via controllable plasmonic heating for thermoplasmonic activation. This enables monitoring of signal molecule dynamics, real-time photothermal and photoacoustic imaging of tumors and lymph node metastasis, and targeted photothermal therapy without unwanted phototoxicity to normal tissues. Our study provides a practical solution to the non-specificity problem in phototherapy and offers precision cancer therapeutic and theranostic strategies. This work may advance the development of ultrasensitive disease diagnosis and precision medicine., A tumor microenvironment-activated photoagent is reported for precise photothermal therapy and photoacoustic imaging via controllable thermoplasmonics. The agent can sensitively image tumors and lymph node metastasis and specifically ablate tumors.

Metastasis remains the primary cause for mortality of breast cancer. Despite advances in current therapeutic agents, patients with metastatic breast cancer still have poor prognoses. Tumor hypoxia, a key microenvironment factor, is emerging as an attractive target to prevent metastasis and is also involved with resistance to phototherapy. Here, we show an effective nanotherapeutic approach based on manganese dioxide-coated polydopamine nanocarriers to trigger robust anti-tumor and anti-metastasis responses against metastatic breast cancer by supplemental oxygenation and multimodal imaging-guided phototherapies. In cancer cells, the produced oxygen by the developed nanoplatform decreases the expression of hypoxia-inducible factors 1\ga to inhibit tumor metastasis, and enhances the efficacy of photodynamic therapy. This nanotherapeutic approach enables the combined photodynamic/photothermal treatments with great inhibition on cell migration and invasion in vitro. Moreover, the nanotherapeutics effectively suppresses primary tumor progress and inhibits lung metastasis in vivo in a breast cancer mouse model with satisfying biosafety. This study suggests that the tumor hypoxia-targeting nanotherapeutics have great potential for preventing and treating metastatic cancers.

While the drop impact dynamics on stationary surfaces has been widely studied, the way a drop impacts a moving solid is by far less known. Here, we report the physical mechanisms of water drops impacting on superhydrophobic surfaces with horizontal motions. We find that a viscous force is created due to the entrainment of a thin air layer between the liquid and solid interfaces, which competes with the capillary and inertia forces, leading to an asymmetric elongation of the drop and an unexpected contact time reduction. Our experimental and theoretical results uncover consolidated scaling relations: the maximum spreading diameter is controlled by both the Weber and capillary numbers D_{max}/D_{0}∼We^{1/4}Ca^{1/6}, while the dimensionless contact time depends on the capillary number τ/τ_{0}∼Ca^{-1/6}. These findings strengthen our fundamental understandings of interactions between drops and moving solids and open up new opportunities for controlling the preferred water repellency through largely unexplored active approaches.

Anion exchange membranes (AEMs) are crucial components for advanced energy and environment processes including alkaline fuel cells, redox flow batteries, and industrial effluent treatment; while low anionic conductivity and poor stability remain the major challenges for the widespread implementation of AEMs. Through molecular engineering, comb-shaped AEMs have been proved possessing the capability of delivering both high conductivity and good alkaline stability. However, how to precisely control the side chain topology and how the chain topology would influence the membrane properties need to be further elucidated. We hereby propose a radically novel and readily scalable route towards the controllable synthesis of comb-shaped AMEs and we were able to determine the length of side chains and the number of ionic groups along the side chains. To probe the effect of side chain topology on membrane properties, two types of AEMs of densely grafted short side chains or loosely grafted long side chains with similar ion exchange capacity (IEC, ∼1.7 mmol/g) were synthesized and compared. We found that the comb-shaped AEMs with loosely grafted long chains (LG-LS-DIm), with higher hydroxide conductivity (55 mS cm−1 at 30 °C) and better alkaline stability (∼80 % of IEC retention after soaking in 2 mol L−1 NaOH solution at 60 °C for 25 days), outperform those with densely grafted short chains (HG-SS-DIm) and the benchmark main-chain type AEMs (DIm-PPO), which is also superior to those of conventional linear AEMs with densely functionalized structure.

Summary The massive-scale integration of renewable electricity into the power grid is impeded by its intrinsic intermittency. The aqueous organic redox flow battery (AORFB) rises as a potential storage solution; however, the choice of positive electrolytes is limited, and the aqueous-soluble organic positive redox-active species reported to date have short lifetimes. Here we report a stable organic molecule for the positive terminal, 4-[3-(trimethylammonio)propoxy]-2,2,6,6-tetramethylpiperidine-1-oxyl (TMAP-TEMPO) chloride, exhibiting high (4.62 M) aqueous solubility. When operated in a practical AORFB against a negative electrolyte comprising BTMAP-viologen at neutral pH, the flow cell displayed an open-circuit voltage of 1.1 volts and a Coulombic efficiency of >99.73%. The capacity retention rate is among the highest of all-organic AORFBs reported to date, at 99.993% per cycle over 1,000 consecutive cycles; the temporal capacity fade rate of 0.026% per h is independent of concentration.

Superhydrophobic surfaces have huge applications in wetting fields. However, compared with natural biological surfaces, artificial superhydrophobic surfaces still show serious deficiencies in the theoretical design and durability. In this work, a robust superhydrophobic surface consisting of a regular array of square pillars with secondary structures on the sidewalls was prepared using low-speed wire electrical discharge machining. We developed the design criteria of regular arrays of square pillars for achieving superhydrophobicity based on interface characteristics and force balance. A series of samples were also prepared to validate the design criteria. The results indicate that the overlap part between the theoretical superhydrophobicity region before and after abrasion leads to stable superhydrophobicity. In addition, specific surfaces transform from the Wenzel state to the Cassie state after abrasion and the contact angle shows a large increase. The design criteria based on the research of predecessors are useful to design superhydrophobic surfaces with robustness.

Low-cost and facile preparation of high-performance nanomaterials has aroused research passion to build non-enzymatic glucose sensor. In this work, uniform and dense Cu nanoparticles were immobilized on ITO electrode by one-step electrochemical deposition, where the Cu nanoparticles/ITO (Cu NPs/ITO) electrode were directly employed for glucose sensing without additional binder. During the deposition, the complexing agent and deposition potential were adjusted to realize the morphology-controlled of Cu NPs and further decrease the aggregation of nanoparticles. Subsequently, the concentration of sodium citrate, deposition potential, NaOH concentration and detection potential on the electrooxidation performances of Cu NPs/ITO were investigated systematically by electrochemical analysis. Under the optimal conditions, the sensor exhibited a high sensitivity of 1005.09 μA mM−1 cm−2 and a wide linear range of 0.0033–3.9019 mM (R2 = 0.998), benefiting from the high conductivity, large surface area and directly electron transfer of binder-free Cu nanoparticles with uniform and dense morphology. Great stability, reproducibility, selectivity and feasible human serum analysis of Cu NPs/ITO were also demonstrated in glucose sensing. Owing to its low-cost, one-step preparation and great performance, this Cu NPs/ITO electrode can be a promising candidate for the construction of non-enzymatic glucose sensor.

Fluorescent nanoparticles exhibit unique optical properties for applications in imaging and sensing. Herein, the enhancement of luminescence emission from self-assembled nanoparticles including gold nanoclusters, cadmium sulphide and near-infrared silver selenide quantum dots are reported. Addition of zinc and pyrophosphate ions induces assembly and disassembly of the particle aggregates and the corresponding intensified and recovery of fluorescence intensity, respectively. The enhancement is due to assembly-enhanced emission of metal nanoclusters and passivation of the surface trap states of quantum dots. With the hydrolysis of pyrophosphate catalyzed by alkaline phosphatase, the released zinc ions from pyrophosphate-zinc ion complexes mediate nanoparticle assembly and lead to luminescence regeneration. The assembly-induced fluorescence enhancement can be applied for sensitive assay of alkaline phosphatase with a detection limit of 3.4 pM in a continuous and real-time way. This method is capable of screening enzyme inhibitor and analyzing biological samples.

Immunoassay is commonly used for the detection of disease biomarkers, but advanced instruments and professional operating are often needed with current techniques. The facile readout strategy for immunoassay is mainly limited to the gold nanoparticles-based colorimetric detection. Here, we show that photothermal nanoparticles can be applied for biosensing and immunoassay with temperature as readout. We develop a plasmonic and photothermal immunoassay that allows straightforward readout by color and temperature based on crystal growth, without advanced equipment. It is demonstrated that alkaline phosphatase-triggered silver deposition on the surface of gold nanostars causes a large blue shift in the localized surface plasmon resonance of the nanosensor, accompanied by photothermal conversion efficiency changes. This approach also allows dual-readout of immunoassays with high sensitivity and great accuracy for the detection of prostate-specific antigen in complex samples. Our strategy provides a promising way for point-of-care testing and may broaden the applicability of programmable nanomaterials for diagnostics.

Droplet impact dynamics on gradient textures at room temperature have been intensively studied in the past decade. The wetting gradient surfaces are reported to direct the droplet motion. In this work, we show an undirectional rebound behavior of impacting droplets on gradient grooved surfaces at high temperature. The impinging droplet rebounds towards the denser microstructure region at contact boiling state, but towards to the sparser region when at Leidenfrost film boiling state. Our analysis indicates that the non-directional rebounding direction is attributed to the unbalanced Young's forces or vapor pressure difference between the droplet and the substrate. In contact boiling regime, the droplet rebounds towards the denser region due to the unbalanced Young's force. However, in the Leidenfrost film boiling region, adequate vapor generated underneath the droplet impedes the direct contact and larger vapor pressure in the denser region causes the droplet to rebound oppositely. This study is envisioned to promote the understanding of droplet dynamics at high temperature and provide promising applications in various systems where regulating droplet motion is needed.

Photodynamic therapy (PDT) utilizes reactive oxygen species (ROS) to treat established diseases and has attracted growing attention in the field of cancer therapy. However, in a tumor microenvironment (TME), the inherent hypoxia and high level of antioxidants severely hamper the efficacy of ROS generation. Here, we describe a cascaded amplifier nanoreactor based on self-assembled nanofusiforms for persistent oxygenation to amplify ROS levels. The nanofusiform assembly is capable of photothermal and photodynamic treatment and regulation of redox oxidation stress by antioxidant depletion to prevent ROS tolerance. The Pt nanozyme decoration of the nanofusiform enables efficient oxygen supplements via Pt nanozyme-catalyzed decomposition of H2O2 overexpressed in TME and generation of O2. Furthermore, the temperature elevation resulted from the photothermal effect of the nanofusiform increases the catalase-like catalytic activity of the Pt nanozyme for boosted oxygen generation. Thus, such a triple cascade strategy using nanozyme-based nanofusiforms amplifies the ROS level by continuous oxygenation, enhancing the efficacy of PDT in vitro and in vivo. Meanwhile, an in vivo multi-modal imaging including near-infrared fluorescence imaging, photothermal imaging, and magnetic resonance imaging achieves precise tumor diagnosis. The rationally designed nanofusiform acts as an efficient ROS amplifier through multidimension strengthening of continuous oxygenation, providing a potential smart nanodrug for cancer therapy.

In the first part of this research, we reported the experimental study of the drop impact on the superhydrophobic circular groove arrays, which resulted in a directional droplet transport. In the second part, we further explored the influence of the Weber number (We), ridge height (H), and the deviation distance (r) between the impacting point and the center of curvature on the lateral offset distance (ΔL) of bouncing drops. The suggested theoretical analysis is in reasonable agreement with the experimental observations. We demonstrate that a Cassie-Wenzel wetting transition occurred within the microstructures of the relief under the threshold Weber number, for example, We ≅ 19-25, which switched the nature of drop bouncing. The dynamic pressure plays a decisive role in the directional droplet transport. The reported investigation may shed light on the solid-liquid interactions occurring on the patterned hierarchical surfaces and open up new opportunities for directional droplet transportation.

Efficient adhesion of gas bubbles in aqueous environments has great application potentials in various gas-related processes, especially in wastewater treatment. In previous research, much attention has been paid to the design of underwater bubbles transport platforms, however, the bubble adhesion abilities of them are explored insufficiently. Herein, we investigated the bubble adhesion abilities of the superhydrophobic V-shaped pattern (SVP) and a designed superhydrophobic tapered groove (STG). It is revealed that the STG exhibits efficient bubble adhesion abilities compared with the SVP, including bubble retention time (t), adhesion volume and holding efficiency (η). In addition, the STG can retain stable adhesion abilities after several adhesion cycles. We believe that these results provide an alternative approach for subaqueous bubble practical applications.

Directional transport of high-temperature droplets enjoys broad application prospects in the fields of drag reduction and heat transfer. In this paper, two adjacent regions with different surface roughness were constructed on 304 stainless steel by laser etching to control the directional movement of high-temperature droplets. It is found that the regions with different surface roughness have different Leidenfrost temperatures, and the Leidenfrost temperature is lower under smaller roughness. When the droplet hits the boundary of the adjacent regions at high temperatures, it will bounce towards the region with larger roughness spontaneously, and the directional bouncing distance tends to first increase and then decrease with the increase of temperature and Weber number. In addition, when the droplet impacts at the boundary of the adjacent regions which have different Leidenfrost temperatures, the two parts of the droplet will be in transition boiling and film boiling respectively. The resulting Young’s force is the main factor that drives the droplets to bounce directionally.

Ferrocene (Fc) is one of the very limited organic catholyte options for aqueous organic flow batteries (AOFBs), a potential electrochemical energy storage solution to the intermittency of renewable electricity. Commercially available Fc derivatives are barely soluble in water, while existing methods for making water-soluble Fc derivatives by appending hydrophilic or charged moieties are tedious and time-consuming, with low yields. Here, a strategy was developed based on host-guest inclusion to acquire water-soluble Fc-based catholytes by simply mixing Fc derivatives with β-cyclodextrins (β-CDs) in water. Factors determining the stability and the electrochemical behavior of the inclusion complexes were identified. When adopted in a neutral pH AOFB, the origin of capacity loss was identified to be a chemical degradation caused by the nucleophilic attack on the center FeIII atom of the oxidized Fc derivatives. By limiting the state of charge, a low capacity fade rate of 0.0073 % h-1 (or 0.0020 % per cycle) was achieved. The proposed strategy may be extended to other families of electrochemically active water-insoluble organic compounds, bringing more electrolyte options for practical AOFB applications.

The aqueous organic flow battery (AOFB) holds enormous potential as an energy storage device for fluctuating renewable electricity by exploiting the redox reactions of water-soluble organic molecules. The current development is impeded by lack of organic molecules adequate as catholyte, yet how the catholyte structure impacts the battery lifetime remains unexplored. Here, six ferrocene derivatives with deliberately tuned chemical structure were devised. They underwent reversible redox reactions in water, and the redox potentials were inversely related to the lowest unoccupied molecular orbital (LUMO) energy of their energized forms. The stability of the ferrocene derivatives was evaluated in full flow cells and in symmetric cells. Density function theory calculations, along with experimental results, revealed that the localized LUMO density on Fe led to fast capacity fading. BQH-Fc, which has the lowest LUMO density on Fe, showed the highest stability. No capacity loss was observed for the BQH-Fc/BTMAP-Vi cell at 0.1 m, and a high capacity retention rate of 99.993 % h-1 was recorded at 1.5 m, which could be attributed to electrolyte crossover. To facilitate explorations of robust and high capacity catholytes, a method was established to predict the water solubility of ferrocene molecules, and calculations were in good accordance with measured values.

Directional transport of liquid droplets is crucial for various applications including water harvesting, anti-icing, and condensation heat transfer. Here, bouncing of water droplets with patterned superhydrophobic surfaces composed of circular equidistant grooves was studied. The directional transport of droplets toward the pole of the grooves was observed. The impact of the Weber number, initial polar distance

Ion-exchange membranes are the core elements for an electrodialysis (ED) separation process. Phase inversion is an effective method, particularly for commercial membrane production. It introduces two different mechanisms, i.e., thermal induced phase separation (TIPS) and diffusion induced phase separation (DIPS). In this study, anion exchange membranes (AEMs) were prepared by grafting a quaternized moiety (QM,2-[dimethylaminomethyl]naphthalen-1-ol) through brominated poly (2,6-dimethyl-1,4-phenylene oxide) (BPPO) via the TIPS method. Those membranes were applied for selective bisulfite (HSO3&minus, ) anion separation using ED. The membrane surface morphology was characterized by SEM, and the compositions were magnified using a high-resolution transmission electron microscope (HRTEM). Notably, the membranes showed excellent substance stability in an alkali medium and in grafting tests performed in a QM-soluble solvent. The ED experiment indicated that the as-prepared membrane exhibited better HSO3&minus, separation performance than the state-of-the-art commercial Neosepta AMX (ASTOM, Japan) membrane.

Slippery liquid-infused porous surfaces (SLIPSs) have recently been intensively investigated because of promising potential in various applications that require water repellency. However, the use of SLIPS is limited by its unsatisfactory oil-storage and -replacement capabilities. Here we designed network surface structures with interconnected microchannels and cross-linked nanosheets, which acted as natural oil reservoirs and vessels. A lubricant can be firmly locked and stored into the networks, leading to an efficient water repellency as well as improved mechanical durability and stability. We further show the surface structures can be applied to anti-icing/deicing, demonstrated by its improved icing-delaying, anti-icing, and deicing properties even after multiple cycles, compared to those on superhydrophobic surfaces (SHSs) and the conventional SLIPSs. We envision that this unique design of the slippery liquid-infused porous network surface (SLIPNS) with robust stability and durability may expand its application in extreme environments.

Membranes with fast and selective transport of protons and cations are required for a wide range of electrochemical energy conversion and storage devices, such as proton‐exchange membrane (PEM) fuel cells and redox flow batteries. Here we report a new approach to designing solution‐processable ion‐selective polymer membranes with both intrinsic microporosity and ion‐conductive functionality. This was achieved by synthesizing polymers with rigid and contorted backbones, which incorporate hydrophobic fluorinated and hydrophilic sulfonic acid functional groups, to produce membranes with negatively‐charged subnanometer‐sized confined ionic channels. The facilitated transport of protons and cations through these membranes, as well as high selectivity towards nanometer‐sized redox‐active molecules, enable efficient and stable operation of an aqueous alkaline quinone redox flow battery and a hydrogen PEM fuel cell. This membrane design strategy paves the way for producing a new‐generation of ion‐exchange membranes for electrochemical energy conversion and storage applications.

Bouncing of water droplets on the post-built superhydrophobic surfaces was studied. The topography of the surfaces was constituted by PDMS conical posts decorated with ZnO nanoparticles. Droplet impact on surface topographies built of posts with varied configuration and separation was studied under different Weber numbers. Faceted spreading and retraction of droplets were observed. Square-, pentagon-, and hexagon-shaped droplets were registered. It was shown that the nature of droplet spreading depended on both the Weber number and the topography of the post arrays. Even bouncing under small Weber numbers

Precise analysis of explosives is important for environmental pollution evaluation and terrorist prevention. However, rapid assay of explosives with high selectivity and sensitivity remains difficult. Here, we show that the gold nanocluster-modified metal-organic frameworks are excellent optical probes for explosive detection. The nanoclusters exhibit enhanced luminescence and selectively respond toward 2,4,6-trinitrotoluene over other explosives with a detection limit of 5 nM and fast response within 1 min. The efficient assay is resulted from the framework-mediated cluster aggregation and TNT binding.

Hypothesis Droplet depositing onto hot surfaces above the so-called Leidenfrost temperature will float on a cushion of its own vapor. The vapor flow below the drop could be rectified by asymmetric surface textures, resulting the self-propelled droplet motion. Asymmetric structures like ratchets are used to rectify Leidenfrost droplet movement. Hence, it is possible to enhance the droplet mobility using surfaces with combined asymmetric macro/micro-structures. Experiments Continuous scale-like microcraters stacked end-to-end were fabricated on steel surfaces by wire electrical discharge machining (WEDM). The crater orientation always vectored towards the machining direction (MD), which oriented the droplet motion. Further, by integrating micro and macro-ratchets, dual-scale ratchets were constructed by one-step process using WEDM. The travelling velocities of Leidenfrost droplets on dual-scale and traditional single-scale ratchets were compared and the enhanced mechanism on dual-scale ratchets was analyzed. Findings One-step process was developed to fabricate transport platforms for Leidenfrost droplets, that continuous scale-like microcraters formed simultaneously on the macroratchets. The highest droplet travelling velocity was achieved compared to previous research. Further study shows that the enhanced drop mobility is attributed to the dual-scale roughness which endows a larger propelling force. This finding presents a high-efficiency method to fabricate transport platforms for Leidenfrost droplets.

Nanomaterials are commonly utilized for amplified immunoassay of biomarkers. However, traditional nanomaterial-based immunoassay usually requires a time-consuming and labor-intensive nanoparticle modification and conjugation process, which impedes their practical applications. Here, a new immunoassay method based on biosynthesized nanomaterials is developed with versatile functions for facile and ultrasensitive detection of cancer biomarker. In this method, the utilized biosynthesized quantum dots (BQDs) allow convenient antibody conjugation and electrode modification, and demonstrate excellent electrochemical and electrochemiluminescent responses. The differential pulse voltammetric, faradaic impedance spectroscopy, and electrochemiluminescent measurements with the BQD-modified electrode show detection limits at picomolar levels as well as good specificity toward human prostate-specific antigen detection. The inherent recognization capability as well as the inherent electrochemical and electrochemiluminescence features thus enable BQDs as good candidates for facile immunosensors with high sensitivity. Such a biosynthesized nanomaterial-based approach opens up the possibility of using innovative designs for nanoparticle-based assays, and developing reliable and practical methods for early disease diagnosis.

Ion exchange membranes (IEMs) play a significant role in fields of energy and environment, for instance fuel cells, diffusion dialysis, electrodialysis, etc. The limited choice of commercially available IEMs has produced a strong demand of fabricating IEMs with improved properties via facile synthetic strategies over the past two decades. Poly(phenylene oxide) (PPO) is considered as a promising polymeric material for constructing practical IEMs, due to its advantages of good physicochemical properties, low manufacturing cost and easy post functionalization. In this review, we present the accumulated efforts in synthetic strategies towards diverse types of PPO-based IEMs. Relation between polymer structures and the resulted features is discussed in detail. Besides, applying IEMs from PPO and its derivatives in fuel cell, diffusion dialysis and electrodialysis is summarized and commented.

A droplet impacting on a superhydrophobic surface exhibits complete bouncing. The impacting process usually consists of spreading and retracting stages, during which the droplet contacts the underlying substrate. Recent research has been devoted to reducing the contact time using textured surfaces with different morphologies or flexibilities. Here, we design submillimeter superhydrophobic ridges and show that impacting droplets bounce off the surface immediately after capillary emptying in a petal-like shape at a certain Weber number range. The absence of a horizontal retraction process in two directions leads to ∼70% reduction in contact time. We demonstrate that the petal bouncing is attributed to the synergistic cooperation of the hierarchical structures and anisotropic property, which endows effective energy storage and release. When touching the bottom of the grooves, obvious flying wings appear along the ridges with a velocity component in the vertical direction, which help the energy releasing process in achieving fast droplet detachment. At higher Weber numbers, the anisotropic surface distorts the mass distribution and promotes uniform fragmentation of the droplet, and therefore the overall contact time is dramatically reduced. Simple analyses are proposed to explain these phenomena, showing a good agreement with the experimental results. The contact time reduction on anisotropic superhydrophobic surfaces is expected to have a great influence on the design and fabrication of anti-icing and self-cleaning surfaces.

Two-dimensional transition metal carbides, MXenes, with large surface area, excellent electrical conductivity and chemical stability, have proved promising for energy storage. However, the irreversible re-stacking and low capacity of MXenes restrict their development and practical applications. Here, the N-doped carbon decorated MXene (Ti 3 C 2 T x @NC) composites were synthesized via an in-situ self-polymerization of dopamine on the surface of Ti 3 C 2 T x followed by a carbonization process. The Ti 3 C 2 T x and Ti 3 C 2 T x @NC were systematically characterized, which have been manifested that NC were equably decorated on the surface and interlayer of Ti 3 C 2 T x sheets and a unique three-dimensional composited nanostructure was fabricated. Such nanostructure can confer both high surface area of NC layer and effective avoidance of the restacking of Ti 3 C 2 T x sheets, whilst, importantly, rendering the composites good conductivity and additional pseudocapacitance. As a result, the optimized Ti 3 C 2 T x @NC-2 composite exhibited a high specific capacitance of 442.2 F g −1 under a current density of 1 A g −1 , which is 281% higher than that of Ti 3 C 2 T x . As a further description, Ti 3 C 2 T x @NC achieved an excellent cycling stability with capacitance retaining 91.9% after 5000 cycles and a high rate capability of 92.5% at 10 A g −1 . Besides, the Ti 3 C 2 T x @NC-2-based symmetric supercapacitor presents a delighted energy density and power density. Therefore, the elaborately designed Ti 3 C 2 T x @NC composites provided a pregnant exploration for energy-related applications.

Here, Ti3C2Tx sheets, a representative of MXenes, with lamellar structure and hydrophilic surface are prepared, and then functionalized with sulfonated polyelectrolyte brushes (Ti3C2Tx-SO3H) through a facile surface-initiated precipitation-polymerization. The Ti3C2Tx-SO3H is then utilized as a new nanofiller to fabricate hybrid proton exchange membrane, where both acidic sulfonated poly (ether ether ketone) (SPEEK) and basic chitosan (CS) are employed as polymer matrixes. The resultant hybrid membranes are systematically characterized and measured including their microstructures, water uptake and proton conduction properties. The results demonstrate that using the sulfonated polyelectrolyte brushes, Ti3C2Tx-SO3H sheets construct efficient proton transfer pathways and connect the inherent conduction channels/paths in polymer phase. This significantly enhances the proton conduction of polymer membrane including SPEEK membrane and CS membrane, under both hydrated condition and anhydrous condition. Particularly, the incorporation of 10 wt.% Ti3C2Tx-SO3H readily offers 144% and 66% increase in proton conductivity, respectively, to SPEEK membrane and CS membrane under hydrated condition. Furthermore, the hybrid membranes achieve improved thermal and mechanical stabilities. These results herald further advances to preparing functionalized MXenes and their relevant hybrid materials with enhanced performances.

Glutathione (GSH) plays a vital role in biological systems and is associated with human pathology. The engineering of semiconductor quantum dots (QDs) as fluorescent probes for GSH sensing and bioimaging is a potential yet rarely reported approach. Herein, we report the in situ growth of manganese dioxide nanosheets (MnO2) on silica-coated semiconductor quantum dots (QD@SiO2), to prepare a stable and biocompatible fluorescent nanoprobe (QD@SiO2-MnO2) for the selective and sensitive detection of GSH. The modification of QD@SiO2 with MnO2 significantly quenched the fluorescence of CdSe/ZnS QDs, yet the addition of GSH efficiently recovered the fluorescence of the nanoprobe due to the decomposition of MnO2 by GSH. This nanosensor showed a rapid response to GSH with a low detection limit, and high selectivity towards GSH over potential interferences. Furthermore, the MnO2-engineered QDs had good biocompatibility and cellular uptake ability, and were successfully applied for the real-time imaging of intracellular GSH. We envision that semiconductor QD-based probes will stimulate the study of GSH dynamics and facilitate the understanding of GSH-related pathophysiological events.

The grid-scale integration of solar or wind energy that fluctuates over time will compromise the stability of the power grid. All-vanadium redox flow battery (VRFB) is among the most feasible electrochemical energy storage solutions, while the grand challenge is to develop membranes that separate vanadium electrolytes effectively and transport protons rapidly. Here we present highly conductive and vanadium sieving microporous membranes from shape persistent Trӧger's Base polymer. The N-rich and microporous polymer skeleton facilitate H+ transport. In contrast, hydrated vanadium ions are blocked due to size exclusion and coulombic repulsion. This increases the H/V selectivity of the membrane to >6300, lowers the membrane resistance to 0.57 Ω cm2, and raises the battery power density to 710.9 mW cm−2. A round-trip energy efficiency of 80% and a coulombic efficiency of >99% are maintained during long periods of charge/discharge. We believe the results will stimulate new directions for advanced VRFB membranes.

Conductive polymer electrolyte membranes are increasingly attractive for a wide range of applications in hydrogen-relevant devices, for instance hydrogen fuel cells. In this study, two-dimensional Ti3C2Tx, a typical representative of the recently developed MXene family, is synthesized and employed as a universal filler for its features of large specific surface area, high aspect ratio, and sufficient terminated -OH groups. The Ti3C2Tx is incorporated into polymer matrix to explore its function on membrane microstructure and proton conduction property. Both phase-separated (acidic Nafion and sulfonated poly(ether ether ketone)) and non-phase-separated (basic chitosan) polymers are utilized as membrane matrixes. The microstructures, physicochemical properties, and proton conduction properties of the membranes are extensively investigated. It is demonstrated that Ti3C2Tx generates significant promotion effect on proton conduction of the composite membrane by facilitating both vehicle-type and Grotthuss-type proton transfer, yielding several times increased proton conductivity for every polymer-based composite membrane under various conditions, and the composite membrane achieves elevated hydrogen fuel cell performance. The stable Ti3C2Tx also reinforces the thermal and mechanical stabilities of these composite membranes. Since the MXene family includes more than 70 members, this exploration is expected to open up new perspectives for expanding their applications, especially as membrane modifiers and proton conductors.

In this study, acidified lithium ion-sieves (HMOs) containing unique inner ionic channels suitable for the transfer of H + are selected as proton-conductive fillers to prepare hybrid membranes for the first time. By using facile distillation-precipitation polymerization process, two types of sulfonated HMOs (SHMOs) are prepared: L-SHMOs, which are modified by sulfonate polyelectrolyte layer, and B-SHMOs, which are sulfonate polyelectrolyte brushes. The results demonstrate that these fillers improve the thermal and mechanical stabilities of chitosan (CS) control membranes. The incorporation of pristine HMOs enhances the water uptakes and proton conduction abilities of hybrid membranes at suitable loading. By comparison, SHMOs-filled membranes possess higher proton conductivities than those of HMO-filled membranes, owing to the additional proton hopping sites of –SO 3 H and acid-base pairs (–SO 3 − ··· + 3 HN–). Moreover, B-SHMO-filled membranes exhibit superior proton conductivities over L -SHMO-filled ones, demonstrating that the polymer brushes on HMOs allow more –SO 3 H groups to form acid-base pairs with CS chains. Particularly, CS/B-SHMO-12 obtains the highest hydrated and anhydrous conductivities of 0.0224 S cm −1 and 10.03 mS cm −1 , enhancing by 91.4% and 98.6% respectively compared with those of CS control membrane under identical conditions. The enhanced proton conductivities offer SHMO-filled membranes elevated cell performances.

The development of bio-inspired interfacial materials with enhanced drop mobility that mimic the innate functionalities of nature will have significant impact on the energy, environment and global healthcare. In spite of extensive progress, the state of the art of interfacial materials have not reached the level of maturity sufficient for industrial applications in terms of scalability, stability and reliability, which are complicated by their operating environments and lack of facile approaches to exquisitely control the local structural texture and chemical composition at multiple length scales. In this review, we focus on the recent advances in the fundamental understanding as well as practical applications of bio-inspired interfacial materials, with an emphasis on the drop impact induced bouncing and coalescence induced jumping behaviors. We also suggest our own perspectives on how to catalyze new discoveries and to foster technological adoption to move this exciting area forward., Comment: 23 pages, 8 figures

Directed motion of liquid droplets is of considerable importance in various water and thermal management technologies. Although various methods to generate such motion have been developed at low temperature, they become rather ineffective at high temperature, where the droplet transits to a Leidenfrost state. In this state, it becomes challenging to control and direct the motion of the highly mobile droplets towards specific locations on the surface without compromising the effective heat transfer. Here we report that the wetting symmetry of a droplet can be broken at high temperature by creating two concurrent thermal states (Leidenfrost and contact-boiling) on a topographically patterned surface, thus engendering a preferential motion of a droplet towards the region with a higher heat transfer coefficient. The fundamental understanding and the ability to control the droplet dynamics at high temperature have promising applications in various systems requiring high thermal efficiency, operational security and fidelity. Controlled motion of a droplet on a hot surface is hampered by the formation of an evaporation layer below the droplet (Leidenfrost effect). But a cleverly patterned surface induces a Leidenfrost–contact-boiling state, directing the droplet’s motion.

Despite the tremendous potential of ratiometric method, its development has been limited by challenges such as the lack of signal amplification. Ratiometric sensing that is highly reliable, sensitive and selective would greatly facilitate optical analysis. Inspired by the natural biocatalysis and cascade catalysis, we demonstrate that the nanoprobe-mediated ratiometric detection coupled with autocatalytic reaction enables fluorescence sensing with ultrahigh sensitivity. Furthermore, the integration of the ratiometric analysis with catalytic cascade reactions allows amplified optical sensing of enzyme activity including alkaline phosphatase or acetylcholinesterase and their inhibitors. Our data show that ratiometric nanoplatforms combined with autocatalytic reaction or catalytic cascade reactions mediated by nanoprobes may represent a viable approach to improve performance of fluorescence sensing.

The addition of exogenous microorganisms is one approach with potential that may also overcome the problem in northern China of slow composting in autumn and winter due to low environmental temperatures. This study investigated the use of supplements of Lactobacillus plantarum (L. plantarum), strains P-8 and LP-10, on the efficiency of sheep manure composting and the quality of the final product. The composting process lasted eight weeks and, during this time, changes in multiple physical-chemical parameters and the compost microbiome were monitored. Microbiota-encoded functions, community structure and physical-chemical parameters were distinct between the two groups. ‘Composting microbiota maturation index’ was proposed to quantitatively compare the impact of maturation on composting microecology. The rapid improvement in composting rate (4 weeks) and quality of the final product suggest that this approach could provide both technological and economic benefits. This work reveals the tremendous potential of L. plantarum as a promoter in composting.

Ebola virus (EBOV) disease is a complex zoonosis that is highly virulent in humans and has caused many deaths. Highly sensitive detection of EBOV is of great importance for early-stage diagnosis for increasing the probability of survival. Herein, we established a cellular-beacon-mediated counting strategy for an ultrasensitive EBOV assay on a micromagnetic platform. The detection platform, which was assisted by on-demand magnetic-field manipulation, showed high integration and enhanced complex-sample pretreatment by magnetophoretic separation and continuous-flow washing. Cellular beacons (i.e., fluorescent cells) with superior optical properties were used as reporters, and each cellular beacon was used as a fluorescent tracking unit to quantify EBOV by counting the numbers of individual fluorescent signals on the micromagnetic platform. This method achieves high sensitivity with a detection limit as low as 2.6 pg/mL, and the detection limit shows little difference in a complex matrix. In addition, it has excellent specificity and good reproducibility. These results indicate that this method proposes an ultrasensitive detection strategy for early diagnosis of the disease.

Reducing the contact time between bouncing droplets and an underlying solid surface is relevant to a broad range of industrial applications, such as anti-icing and self-cleaning. Previous work has found that placing cylindrical obstacles on the substrate leads to a reduction in contact time. For obstacles large compared to the drop, this is a result of hydrodynamic coupling between the azimuthal and axial spreading directions. For obstacles small compared to the drop, the reduction in contact time is interpreted as being due to fast retraction along the cylindrical ridge, followed by drop breakup. Here we use simulations to discuss in greater detail the effect of varying the obstacle size on the dynamics of the drop bouncing. We investigate the crossover between the two regimes and explain why the contact time is minimized when the radii of the drop and the cylindrical obstacle are comparable.

Recent research has shown that the use of submillimeter-scale tapered post arrays could generate the so-called pancake bouncing, which is characterized by the fast shedding of impinging drops from the surface in a pancake shape without undergoing the retraction stage as observed on conventional superhydrophobic surfaces. Despite this exciting discovery, the fabrication of this unique superhydrophobic surface with tapered post arrays involves complex processes, hindering its wide applications in practical sectors. Here, we report on the facile strategy to prepare a new hierarchical multilayered superhydrophobic surface directly from commercially available porous matrix that allows for efficient drop shedding. Further study shows that the enhanced drop mobility observed on such a surface is attributed to the synergistic cooperation of hierarchical structures endowing an adequate energy storage and effective energy release. The facile fabrication of superhydrophobic surface with enhanced drop mobility may find many practical applications including anti-icing, dropwise condensation and self-cleaning.

Engineering surfaces that promote rapid drop detachment is of importance to a wide range of applications including anti-icing, dropwise condensation6, and self-cleaning. Here we show how superhydrophobic surfaces patterned with lattices of submillimetre-scale posts decorated with nano-textures can generate a counter-intuitive bouncing regime: drops spread on impact and then leave the surface in a flattened, pancake shape without retracting. This allows for a four-fold reduction in contact time compared to conventional complete rebound. We demonstrate that the pancake bouncing results from the rectification of capillary energy stored in the penetrated liquid into upward motion adequate to lift the drop. Moreover, the timescales for lateral drop spreading over the surface and for vertical motion must be comparable. In particular, by designing surfaces with tapered micro/nanotextures which behave as harmonic springs, the timescales become independent of the impact velocity, allowing the occurrence of pancake bouncing and rapid drop detachment over a wide range of impact velocities., Comment: 11 pages, 4 figures, 31 references, + 5 pages of supplementary information