Showing papers by "Donghua University published in 2018"

Design and Mechanisms of Asymmetric Supercapacitors.

Abstract: Ongoing technological advances in diverse fields including portable electronics, transportation, and green energy are often hindered by the insufficient capability of energy-storage devices By taking advantage of two different electrode materials, asymmetric supercapacitors can extend their operating voltage window beyond the thermodynamic decomposition voltage of electrolytes while enabling a solution to the energy storage limitations of symmetric supercapacitors This review provides comprehensive knowledge to this field We first look at the essential energy-storage mechanisms and performance evaluation criteria for asymmetric supercapacitors to understand the wide-ranging research conducted in this area Then we move to the recent progress made for the design and fabrication of electrode materials and the overall structure of asymmetric supercapacitors in different categories We also highlight several key scientific challenges and present our perspectives on enhancing the electrochemical performance of future asymmetric supercapacitors

Molecular-channel driven actuator with considerations for multiple configurations and color switching.

Abstract: The ability to achieve simultaneous intrinsic deformation with fast response in commercially available materials that can safely contact skin continues to be an unresolved challenge for artificial actuating materials. Rather than using a microporous structure, here we show an ambient-driven actuator that takes advantage of inherent nanoscale molecular channels within a commercial perfluorosulfonic acid ionomer (PFSA) film, fabricated by simple solution processing to realize a rapid response, self-adaptive, and exceptionally stable actuation. Selective patterning of PFSA films on an inert soft substrate (polyethylene terephthalate film) facilitates the formation of a range of different geometries, including a 2D (two-dimensional) roll or 3D (three-dimensional) helical structure in response to vapor stimuli. Chemical modification of the surface allowed the development of a kirigami-inspired single-layer actuator for personal humidity and heat management through macroscale geometric design features, to afford a bilayer stimuli-responsive actuator with multicolor switching capability. Intrinsic deformation with fast response in commercially available materials that can safely contact skin continues to be a challenge for artificial actuating materials. Here the authors incorporate nanoscale molecular channels within perfluorosulfonic acid ionomer for self-adaptive and ambient-driven actuation.

Recent progress on sodium ion batteries: potential high-performance anodes

Abstract: Due to massively growing demand arising from energy storage systems, sodium ion batteries (SIBs) have been recognized as the most attractive alternative to the current commercialized lithium ion batteries (LIBs) owing to the wide availability and accessibility of sodium. Unfortunately, the low energy density, inferior power density and poor cycle life are still the main issues for SIBs in the current drive to push the entire technology forward to meet the benchmark requirements for commercialization. Over the past few years, tremendous efforts have been devoted to improving the performance of SIBs, in terms of higher energy density and longer cycling lifespans, by optimizing the electrode structure or the electrolyte composition. In particular, among the established anode systems, those materials, such as metals/alloys, phosphorus/phosphides, and metal oxides/sulfides/selenides, that typically deliver high theoretical sodium-storage capacities have received growing interest and achieved significant progress. Although some review articles on electrodes for SIBs have been published already, many new reports on these anode materials are constantly emerging, with more promising electrochemical performance achieved via novel structural design, surface modification, electrochemical performance testing techniques, etc. So, we herein summarize the most recent developments on these high-performance anode materials for SIBs in this review. Furthermore, the different reaction mechanisms, the challenges associated with these materials, and effective approaches to enhance performance are discussed. The prospects for future high-energy anodes in SIBs are also discussed.

Biomimetic and Superwettable Nanofibrous Skins for Highly Efficient Separation of Oil-in-Water Emulsions

Abstract: Developing a feasible and efficient separation membrane for the purification of highly emulsified oily wastewater is of significance but challenging due to the critical limitations of low flux and serious membrane fouling. Herein, a biomimetic and superwettable nanofibrous skin on an electrospun fibrous membrane via a facile strategy of synchronous electrospraying and electrospinning is created. The obtained nanofibrous skin possesses a lotus-leaf-like micro/nanostructured surface with intriguing superhydrophilicity and underwater superoleophobicity, which are due to the synergistic effect of the hierarchical roughness and hydrophilic polymeric matrix. The ultrathin, high porosity, sub-micrometer porous skin layer results in the composite nanofibrous membranes exhibiting superior performances for separating both highly emulsified surfactant-free and surfactant-stabilized oil-in-water emulsions. An ultrahigh permeation flux of up to 5152 L m−2 h−1 with a separation efficiency of >99.93% is obtained solely under the driving of gravity (≈1 kPa), which was one order of magnitude higher than that of conventional filtration membranes with similar separation properties, showing significant applicability for energy-saving filtration. Moreover, with the advantage of an excellent antioil fouling property, the membrane exhibits robust reusability for long-term separation, which is promising for large-scale oily wastewater remediation.

A supramolecular biomimetic skin combining a wide spectrum of mechanical properties and multiple sensory capabilities.

Abstract: Biomimetic skin-like materials, capable of adapting shapes to variable environments and sensing external stimuli, are of great significance in a wide range of applications, including artificial intelligence, soft robotics, and smart wearable devices. However, such highly sophisticated intelligence has been mainly found in natural creatures while rarely realized in artificial materials. Herein, we fabricate a type of biomimetic iontronics to imitate natural skins using supramolecular polyelectrolyte hydrogels. The dynamic viscoelastic networks provide the biomimetic skin with a wide spectrum of mechanical properties, including flexible reconfiguration ability, robust elasticity, extremely large stretchability, autonomous self-healability, and recyclability. Meanwhile, polyelectrolytes' ionic conductivity allows multiple sensory capabilities toward temperature, strain, and stress. This work provides not only insights into dynamic interactions and sensing mechanism of supramolecular iontronics, but may also promote the development of biomimetic skins with sophisticated intelligence similar to natural skins.

Comparison of heavy metal removals from aqueous solutions by chemical precipitation and characteristics of precipitates

Abstract: Typical chemical precipitation methods using lime (Ca(OH)2), soda ash (Na2CO3) and sodium sulfide (Na2S) for removals of heavy metals (i.e. Zn (II), Cu (II) and Pb (II)) from aqueous solutions were compared by jar tests. A focus was especially given to particle size differences and chemical phase conversion of precipitates. A removal of 99.99% from aqueous solutions with three precipitants was achieved for copper and zinc at an initial concentration of 100 mg/L. And lead was efficiently removed (99.75%) by sodium sulfide. In contrast, the maximal lead removals with lime or soda ash precipitation were only 76.14% and 97.78%. The mean particle size of precipitates was in the range of 55 nm–45 μm, depending on properties of precipitants and heavy metal to precipitant ratios. The settling performance of the sludge derived from precipitation was dominated by particle size and Zeta-potential of precipitates. It was observed that ultra-fine copper sulfide particles resulted from the precipitation were around 55 nm and did not settle in 12 h due to electrostatic repulsion force between particles. The main compounds in the sludge obtained from precipitation were metal hydroxides and metal sulfides. However, spontaneous dehydration of metal hydroxide, oxidation of sulfide and atmospheric carbonation were identified by means of XRD and thermal analyses, which is invaluable to the disposal and utilization of the sludge.

A Stretchable Yarn Embedded Triboelectric Nanogenerator as Electronic Skin for Biomechanical Energy Harvesting and Multifunctional Pressure Sensing.

Abstract: Flexible and stretchable physical sensors capable of both energy harvesting and self-powered sensing are vital to the rapid advancements in wearable electronics Even so, there exist few studies that can integrate energy harvesting and self-powered sensing into a single electronic skin Here, a stretchable and washable skin-inspired triboelectric nanogenerator (SI-TENG) is developed for both biomechanical energy harvesting and versatile pressure sensing A planar and designable conductive yarn network constructed from a three-ply-twisted silver-coated nylon yarn is embedded into flexible elastomer, endowing the SI-TENG with desired stretchability, good sensitivity, high detection precision, fast responsivity, and excellent mechanical stability With a maximum average power density of 230 mW m-2 , the SI-TENG is able to light up 170 light-emitting diodes, charge various capacitors, and drive miniature electronic products As a self-powered multifunctional sensor, the SI-TENG is adopted to monitor human physiological signals, such as arterial pulse and voice vibrations Furthermore, an intelligent prosthetic hand, a self-powered pedometer/speedometer, a flexible digital keyboard, and a proof-of-concept pressure-sensor array with 8 × 8 sensing pixels are successively demonstrated to further confirm its versatile application prospects Based on these merits, the developed SI-TENG has promising applications in wearable powering technology, physiological monitoring, intelligent prostheses, and human-machine interfaces

Ultralight and fire-resistant ceramic nanofibrous aerogels with temperature-invariant superelasticity

Abstract: Ultralight aerogels that are both highly resilient and compressible have been fabricated from various materials including polymer, carbon, and metal. However, it has remained a great challenge to realize high elasticity in aerogels solely based on ceramic components. We report a scalable strategy to create superelastic lamellar-structured ceramic nanofibrous aerogels (CNFAs) by combining SiO2 nanofibers with aluminoborosilicate matrices. This approach causes the random-deposited SiO2 nanofibers to assemble into elastic ceramic aerogels with tunable densities and desired shapes on a large scale. The resulting CNFAs exhibit the integrated properties of flyweight densities of >0.15 mg cm-3, rapid recovery from 80% strain, zero Poisson's ratio, and temperature-invariant superelasticity to 1100°C. The integral ceramic nature also provided the CNFAs with robust fire resistance and thermal insulation performance. The successful synthesis of these fascinating materials may provide new insights into the development of ceramics in a lightweight, resilient, and structurally adaptive form.

Atomic cobalt as an efficient electrocatalyst in sulfur cathodes for superior room-temperature sodium-sulfur batteries.

Abstract: The low-cost room-temperature sodium-sulfur battery system is arousing extensive interest owing to its promise for large-scale applications. Although significant efforts have been made, resolving low sulfur reaction activity and severe polysulfide dissolution remains challenging. Here, a sulfur host comprised of atomic cobalt-decorated hollow carbon nanospheres is synthesized to enhance sulfur reactivity and to electrocatalytically reduce polysulfide into the final product, sodium sulfide. The constructed sulfur cathode delivers an initial reversible capacity of 1081 mA h g−1 with 64.7% sulfur utilization rate; significantly, the cell retained a high reversible capacity of 508 mA h g−1 at 100 mA g−1 after 600 cycles. An excellent rate capability is achieved with an average capacity of 220.3 mA h g−1 at the high current density of 5 A g−1. Moreover, the electrocatalytic effects of atomic cobalt are clearly evidenced by operando Raman spectroscopy, synchrotron X-ray diffraction, and density functional theory. Room-temperature sodium-sulfur batteries hold promise, but are hindered by low reversible capacity and fast capacity fade. Here the authors construct a multifunctional sulfur host comprised of cobalt-decorated carbon nanospheres that impart attractive performance as a cathode in a sodium sulfide battery.

Construction of iron oxide nanoparticle-based hybrid platforms for tumor imaging and therapy

Abstract: The aim of this original review is to highlight and analyze the most recent progress and challenges in the synthesis and surface modifications of superparamagnetic iron oxide (Fe3O4) nanoparticles (NPs) for multimodal imaging and therapy applications, which represent important fields in medicine in general and cancer in particular Thus, the oncology domain is rapidly moving to a more personalized medicine including precision imaging and theranostic approaches Novel biocompatible Fe3O4 nanoparticulate systems have been designed for enhanced and targeted cellular uptake by surface layer coating modifications, to have improved r2 relaxivity for sensitive magnetic resonance (MR) imaging applications, to have the ability to be used for dual mode imaging, and to be used for imaging-guided cancer therapy In this review, we analyzed in depth the new strategies for generating biocompatible multifunctional Fe3O4 nanoplatforms for both the diagnosis and therapy of cancer

Hyaluronic Acid and Polyethylene Glycol Hybrid Hydrogel Encapsulating Nanogel with Hemostasis and Sustainable Antibacterial Property for Wound Healing

Abstract: Immediate hemorrhage control and anti-infection play important roles in the wound management. Besides, a moist environment is also beneficial for wound healing. Hydrogels are promising materials in urgent hemostasis and drug release. However, hydrogels have the disadvantage of rapid release profiles, leading to the exposure to high drug concentrations. In this study, we constructed hybrid hydrogels with rapid hemostasis and sustainable antibacterial property combining aminoethyl methacrylate hyaluronic acid (HA-AEMA) and methacrylated methoxy polyethylene glycol (mPEG-MA) hybrid hydrogels and chlorhexidine diacetate (CHX)-loaded nanogels. The CHX-loaded nanogels (CLNs) were prepared by the enzyme degradation of CHX-loaded lysine-based hydrogels. The HA-AEMA and mPEG-MA hybrid hydrogel loaded with CLNs (labeled as Gel@CLN) displayed a three-dimensional microporous structure and exhibited excellent swelling, mechanical property, and low cytotoxicity. The Gel@CLN hydrogel showed a prolonged release period of...

Efficient Supercapacitor Energy Storage Using Conjugated Microporous Polymer Networks Synthesized from Buchwald–Hartwig Coupling

Abstract: Supercapacitors have received increasing interest as energy storage devices due to their rapid charge-discharge rates, high power densities, and high durability. In this work, novel conjugated microporous polymer (CMP) networks are presented for supercapacitor energy storage, namely 3D polyaminoanthraquinone (PAQ) networks synthesized via Buchwald-Hartwig coupling between 2,6-diaminoanthraquinone and aryl bromides. PAQs exhibit surface areas up to 600 m2 g-1 , good dispersibility in polar solvents, and can be processed to flexible electrodes. The PAQs exhibit a three-electrode specific capacitance of 576 F g-1 in 0.5 m H2 SO4 at a current of 1 A g-1 retaining 80-85% capacitances and nearly 100% Coulombic efficiencies (95-98%) upon 6000 cycles at a current density of 2 A g-1 . Asymmetric two-electrode supercapacitors assembled by PAQs show a capacitance of 168 F g-1 of total electrode materials, an energy density of 60 Wh kg-1 at a power density of 1300 W kg-1 , and a wide working potential window (0-1.6 V). The asymmetric supercapacitors show Coulombic efficiencies up to 97% and can retain 95.5% of initial capacitance undergo 2000 cycles. This work thus presents novel promising CMP networks for charge energy storage.

Daylight-driven rechargeable antibacterial and antiviral nanofibrous membranes for bioprotective applications.

Abstract: Emerging infectious diseases (EIDs) are a significant burden on global economies and public health. Most present personal protective equipment used to prevent EID transmission and infections is typically devoid of antimicrobial activity. We report on green bioprotective nanofibrous membranes (RNMs) with rechargeable antibacterial and antiviral activities that can effectively produce biocidal reactive oxygen species (ROS) solely driven by the daylight. The premise of the design is that the photoactive RNMs can store the biocidal activity under light irradiation and readily release ROS under dim light or dark conditions, making the biocidal function "always online." The resulting RNMs exhibit integrated properties of fast ROS production, ease of activity storing, long-term durability, robust breathability, interception of fine particles (>99%), and high bactericidal (>99.9999%) and virucidal (>99.999%) efficacy, which enabled to serve as a scalable biocidal layer for protective equipment by providing contact killing against pathogens either in aerosol or in liquid forms. The successful synthesis of these fascinating materials may provide new insights into the development of protection materials in a sustainable, self-recharging, and structurally adaptive form.

Versatile Core–Sheath Yarn for Sustainable Biomechanical Energy Harvesting and Real-Time Human-Interactive Sensing

Abstract: Modern electronics, which are indispensable for human health, safety, and communication, present a wide spectrum of opportunities to evolve our society into an intelligent world.[1–3] To this end, considerable attention has been paid to wearable and flexible electronics, owing to their promising applications in a vast number of fields, ranging from flexible power supply,[4–6] stretchable circuitries,[7] personal healthcare/biomedical monitoring,[8,9] artificial electronic skin,[10,11] to wearable human-interactive interface.[12] Among them, numerous types of selfpowered functional sensors for health monitoring,[13] motion tracking,[14] medical care,[15] personal protection, and security[16] have been developed, which present an exciting opportunity to measure human physiology and mobility signals in a continuous, real-time, and noninvasive manner. However, the further advancement of wearable electronics still faces several critical challenges. First, the operations of these wearable electronics usually require external power sources. Conventional The emergence of stretchable textile-based mechanical energy harvester and self-powered active sensor brings a new life for wearable functional electronics. However, single energy conversion mode and weak sensing capabilities have largely hindered their development. Here, in virtue of silver-coated nylon yarn and silicone rubber elastomer, a highly stretchable yarn-based triboelectric nanogenerator (TENG) with coaxial core–sheath and built-in spring-like spiral winding structures is designed for biomechanical energy harvesting and real-time human-interactive sensing. Based on the two advanced structural designs, the yarn-based TENG can effectively harvest or respond rapidly to omnifarious external mechanical stimuli, such as compressing, stretching, bending, and twisting. With these excellent performances, the yarn-based TENG can be used in a self-counting skipping rope, a self-powered gesture-recognizing glove, and a real-time golf scoring system. Furthermore, the yarn-based TENG can also be woven into a large-area energy-harvesting fabric, which is capable of lighting up light emitting diodes (LEDs), charging a commercial capacitor, powering a smart watch, and integrating the four operational modes of TENGs together. This work provides a new direction for textile-based multimode mechanical energy harvesters and highly sensitive self-powered motion sensors with potential applications in sustainable power supplies, self-powered wearable electronics, personalized motion/health monitoring, and real-time human-machine interactions.

Energy-Delay Tradeoff for Dynamic Offloading in Mobile-Edge Computing System With Energy Harvesting Devices

Abstract: Mobile-edge computing (MEC) has aroused significant attention for its performance to accelerate application's operation and enrich user's experience. With the increasing development of green computing, energy harvesting (EH) is considered as an available technology to capture energy from circumambient environment to supply extra energy for mobile devices. In this paper, we propose an online dynamic tasks assignment scheduling to investigate the tradeoff between energy consumption and execution delay for an MEC system with EH capability. We formulate it into an average weighted sum of energy consumption and execution delay minimization problem of mobile device with the stability of buffer queues and battery level as constraints. Based on the Lyapunov optimization method, we obtain the optimal scheduling about the CPU-cycle frequencies of mobile device and transmit power for data transmission. Besides, the dynamic online tasks offloading strategy is developed to modify the data backlogs of queues. The performance analysis shows the stability of the battery energy level and the tradeoff between energy consumption and execution delay. Moreover, the MEC system with EH devices and task buffers implements the high energy efficient and low latency communications. The performance of the proposed online algorithm is validated with extensive trace-driven simulations.

Coaxial extrusion bioprinting of 3D microfibrous constructs with cell-favorable gelatin methacryloyl microenvironments.

Abstract: Bioinks with shear-thinning/rapid solidification properties and strong mechanics are usually needed for the bioprinting of three-dimensional (3D) cell-laden constructs. As such, it remains challenging to generate soft constructs from bioinks at low concentrations that are favorable for cellular activities. Herein, we report a strategy to fabricate cell-laden constructs with tunable 3D microenvironments achieved by bioprinting of gelatin methacryloyl (GelMA)/alginate core/sheath microfibers, where the alginate sheath serves as a template to support and confine the GelMA pre-hydrogel in the core during the extrusion process, allowing for subsequent UV crosslinking. This novel strategy minimizes the bioprinting requirements for the core bioink, and facilitates the fabrication of cell-laden GelMA constructs at low concentrations. We first showed the capability of generating various alginate hollow microfibrous constructs using a coaxial nozzle setup, and verified the diffusibility and perfusability of the bioprinted hollow structures that are important for the tissue engineering applications. More importantly, the hollow alginate microfibers were then used as templates for generating cell-laden GelMA constructs with soft microenvironments, by using GelMA pre-hydrogel as the bioink for the core phase during bioprinting. As such, GelMA constructs at extremely low concentrations (<2.0%) could be extruded to effectively support cellular activities including proliferation and spreading for various cell types. We believe that our strategy is likely to provide broad opportunities in bioprinting of 3D constructs with cell-favorable microenvironments for applications in tissue engineering and pharmaceutical screening.

Continuous, Spontaneous, and Directional Water Transport in the Trilayered Fibrous Membranes for Functional Moisture Wicking Textiles

Abstract: Directional water transport is a predominant part of functional textiles used for continuous sweat release in daily life. However, it has remained a great challenge to design such textiles which ensure continuous directional water transport and superior prevention of water penetration in the reverse direction. Here, a scalable strategy is reported to create trilayered fibrous membranes with progressive wettability by introducing a transfer layer, which can guide the directional water transport continuously and spontaneously, thus preventing the skin from being rewetted. The resulting trilayered fibrous membranes exhibit a high one-way transport index R (1021%) and a desired breakthrough pressure (16.1 cm H2 O) in the reverse direction, indicating an ultrahigh directional water transport capacity. Moreover, on the basis of water transport behavior, a plausible mechanism is proposed to provide insight into the integrative and cooperative driving forces at the interfaces of trilayered hydrophobic/transfer/superhydrophilic fibrous membranes. The successful synthesis of such fascinating materials would be valuable for the design of functional textiles with directional water transport properties for personal drying applications.

High-capacity rechargeable batteries based on deeply cyclable lithium metal anodes.

Abstract: Discovering new chemistry and materials to enable rechargeable batteries with higher capacity and energy density is of paramount importance. While Li metal is the ultimate choice of a battery anode, its low efficiency is still yet to be overcome. Many strategies have been developed to improve the reversibility and cycle life of Li metal electrodes. However, almost all of the results are limited to shallow cycling conditions (e.g., 1 mAh cm −2 ) and thus inefficient utilization ( −2 with average Coulombic efficiency >98% in a commercial LiPF 6 /carbonate electrolyte. The high performance is enabled by slow release of LiNO 3 into the electrolyte and its subsequent decomposition to form a Li 3 N and lithium oxynitrides (LiN x O y )-containing protective layer which renders reversible, dendrite-free, and highly dense Li metal deposition. Using the developed Li metal electrodes, we construct a Li-MoS 3 full cell with the anode and cathode materials in a close-to-stoichiometric amount ratio. In terms of both capacity and energy, normalized to either the electrode area or the total mass of the electrode materials, our cell significantly outperforms other laboratory-scale battery cells as well as the state-of-the-art Li ion batteries on the market.

Exceptional thermoelectric properties of flexible organic−inorganic hybrids with monodispersed and periodic nanophase

Abstract: Flexible organic−inorganic hybrids are promising thermoelectric materials to recycle waste heat in versatile formats However, current organic/inorganic hybrids suffer from inferior thermoelectric properties due to aggregate nanostructures Here we demonstrate flexible organic−inorganic hybrids where size-tunable Bi2Te3 nanoparticles are discontinuously monodispersed in the continuous conductive polymer phase, completely distinct from traditional bi-continuous hybrids Periodic nanofillers significantly scatter phonons while continuous conducting polymer phase provides favored electronic transport, resulting in ultrahigh power factor of ~1350 μW m−1 K−2 and ultralow in-plane thermal conductivity of ~07 W m−1 K−1 Consequently, figure-of-merit (ZT) of 058 is obtained at room temperature, outperforming all reported organic materials and organic−inorganic hybrids Thermoelectric properties of as-fabricated hybrids show negligible change for bending 100 cycles, indicating superior mechanical flexibility These findings provide significant scientific foundation for shaping flexible thermoelectric functionality via synergistic integration of organic and inorganic components The potential of flexible organic/inorganic hybrids for thermoelectrics is limited by the inability to control their microstructure Here, the authors demonstrate polymer-nanoparticle hybrids with a monodispersed, periodic nanophase that shows high thermoelectric performance at room temperature

A Dendritic Nickel Cobalt Sulfide Nanostructure for Alkaline Battery Electrodes

Abstract: A uniform dendritic NiCo 2 S 4 at NiCo 2 S 4 hierarchical nanostructure of width ≈100 nm is successfully designed and synthesized. From kinetic analysis of the electrochemical reactions, those electrodes function in rechargeable alkaline batteries (RABs). The dendritic structure exhibited by the electrodes has a high discharge-specific capacity of 4.43 mAh cm -2 at a high current density of 240 mA cm -2 with a good rate capability of 70.1% after increasing the current densities from 40 to 240 mA cm -2 . At low scan rate of 0.5 mV s -1 in cyclic voltammetry test, the semidiffusion controlled electrochemical reaction contributes ≈92% of the total capacity, this value decreases to ≈43% at a high scan rate of 20 mV s -1 . These results enable a detailed analysis of the reaction mechanism for RABs and suggest design concepts for new electrode materials.

Biomimetic Fibrous Murray Membranes with Ultrafast Water Transport and Evaporation for Smart Moisture-Wicking Fabrics.

Abstract: Both antigravity directional water transport and ultrafast evaporation are critical to achieving a high-performance moisture-wicking fabric. The transpiration in vascular plants possess both of these features, which is due to their optimized hierarchical structure composed of multibranching porous networks following Murray's law. However, it remains a great challenge to simultaneously realize the ultrafast water transport and evaporation by mimicking nature's Murray networks in the synthetic materials. Here, we report a synergistic assembly strategy to create a biomimetic micro- and nanofibrous membrane with antigravity directional water transport and quick-dry performance by combining a multibranching porous structure and surface energy gradient, overcoming previous limitations. The resulting fiber-based porous Murray membranes exhibit an ultrahigh one-way transport capability ( R) of 1245%, a desired overall moisture management capability (OMMC) of 0.94, and an outstanding water evaporation rate of 0.67 g h-1 (5.8 and 2.1 times higher than the cotton fabric and Coolmax fabric, respectively). Overall, the successful synthesis of these biomimetic porous Murray membranes should serve as a source of inspiration for the development of moisture-wicking technologies, providing personal comfort in hot or humid environments.

A Tough and Stiff Hydrogel with Tunable Water Content and Mechanical Properties Based on the Synergistic Effect of Hydrogen Bonding and Hydrophobic Interaction

Abstract: Hydrogels are usually recognized as soft and weak materials, the poor mechanical properties of which greatly limit their applications as structural elements. Designing of hydrogels with high strength and high modulus has both fundamental and practical significances. Herein we report a series of tough, stiff, and transparent hydrogels facilely prepared by copolymerization of 1-vinylimidazole and methacrylic acid in dimethyl sulfoxide followed by solvent exchange to water. The equilibrated hydrogels with water content of 50–60 wt % possessed excellent mechanical properties, with tensile breaking stress, breaking strain, Young’s modulus, and tearing fracture energy of 1.3–5.4 MPa, 40–330%, 20–170 MPa, and 600–4500 J/m2, respectively. These tough hydrogels were also stable over a wide pH range (2 ≤ pH ≤ 10), resulting from the formation of dense and robust hydrogen bonds between imidazole and carboxylic acid groups. Moreover, the water content and mechanical properties of one gel can be adjusted over a wide r...