Transparent ultrahigh-molecular-weight polyethylene/MXene films with efficient UV-absorption for thermal management.

The rational use and conversion of energy are the primary means for achieving the goal of carbon neutrality. MXenes can be used for photothermal conversion, but their opaque appearance limits wider applications. Herein, we successfully develop visible-light transparent and UV-absorbing polymer composite film by solution blending the MXene with polyethylene and then vacuum pressing. The resulting film could be quickly heated to 65 °C under 400 mW cm-2 light irradiation and maintained over 85% visible-light transmittance as well as low haze (<12%). The findings of the indoor heat insulation test demonstrate that the temperature of the glass house model covered by this film was 6-7 °C lower than that of the uncovered model, revealing the potential of transparent film in energy-saving applications. In order to mimic the energy-saving condition of the building in various climates, a typical building model with this film as the outer layer of the window was created using the EnergyPlus building energy consumption software. According to predictions, they could reduce yearly refrigeration energy used by 31-61 MJ m-2, and 3%-12% of the total energy used for refrigeration in such structures. This work imply that the film has wide potential for use as transparent devices in energy-related applications.

Carboxymethyl cellulose and metal-organic frameworks immobilized into polyacrylamide hydrogel for ultrahigh efficient and selective adsorption U(VI) from seawater.

Metal-organic frameworks (MOF)-polymer hybrid hydrogel solves the processable forming of MOF powder and energy consumption of uranium extraction. However, the hybrid hydrogel by conventional synthesis methods inevitably lead to MOF agglomeration, poor filler-polymer interfacial compatibility and slowly adsorption. Herein, we designed that ZIF-67 was implanted into the carboxymethyl cellulose/polyacrylamide (CMC/PAM) by network-repairing strategy. The carboxyl and amino groups on the surface of CMC/PAM drive the uniform growth of ZIF-67 inside the CMC/PAM, which form an array of oriented and penetrating microchannels through coordination bonds. Our strategy eliminate the ZIF-67 agglomeration, increase the interfacial compatibility between MOF and polymer. The method also improve the free and fast diffusion of uranium in CMC/PAM/ZIF-67 hydrogel. According to the experimental, these enhancements synergistically enabled the CMC/PAM/ZIF-67 have a maximum adsorption capacity of 952 mg g-1. The adsorption process of CMC/PAM/ZIF-67 fits well with pseudo-second-order model and Langmuir isotherm. Meanwhile, the CMC/PAM/ZIF-67 maintain a high removal rate (87.3 %) and chemical stability even during ten adsorption-desorption cycles. It is worth noting that the adsorption amount of CMC/PAM/ZIF-67 in real seawater is 9.95 mg g-1 after 20 days, which is an ideal candidate adsorbent for uranium extraction from seawater.

Polyethylene fibers containing directional microchannels for passive radiative cooling.

Passive radiative cooling (PRC) that realizes thermal management without consuming any energy has attracted increasing attention. Unfortunately, polymer fibers with radiative cooling function fabricated via a facile, continuous, large-scale and eco-friendly method have been scarcely reported. Herein, polyethylene fibers containing directional microchannels (PFCDM) are facilely fabricated via melt extrusion and water leaching. Interestingly, fabric based on such hydrophobic PFCDM shows high sunlight reflectivity (93.6%), and mid-infrared emissivity (93.9%), endowing it with remarkable PRC performance. Compared with other reported examples, the as-prepared PFDCM fabric has the highest cooling power (i.e., 104.285 W m-2) and temperature drop (i.e., 27.71 °C). Furthermore, decent self-cleaning performance can keep the PFCDM fabric away from contamination and enable it to retain an excellent radiative cooling effect. The method proposed to fabricate PFCDM in this paper will widen the potential application of thermoplastic polyolefins in the field of radiative cooling.

Regulating microstructures of aerogels by controlling phase separation mechanism for improving specific surface area and energy harvesting.

Aerogels with 3D porous structures have been attracting increasing attention among functional materials due to their advantages of being lightweight and high specific surface area. Precise control of the porous structure of aerogel is essential to improve its performance. In this work, polylactic acid (PLA) aerogels with distinctly different microstructures were fabricated by precisely controlling the phase separation behavior of the ternary solution system. Rheological and theoretical analyses have revealed that the interactions between polymer molecules, solvents and non-solvents play a crucial role in determining the nucleation and growth of poor olymer and rich polymer phases. By adjusting the non-solvent type and the solution composition, aerogels with spider network structure, bead-like connected microsphere structure, and cluster petal structure were obtained. Ideal spinodal phase separation conditions were obtained to produce aerogels with a homogeneous fiber network structure. The optimum PLA aerogel achieved an extremely porosity of 96 % and a high specific surface area of 114 m2/g, which rendered it with excellent triboelectric generation performance. Thus, this work provides fundamental insights into the precise regulation of the phase separation behavior and the structure of the aerogel, which can help boost the performance and expand the applications of PLA aerogels.

Ag Nanoparticles-Coated Shish-Kebab Superstructure Film for Wearable Heater.

Passive and active wearable heaters have received widespread attention due to their efficient utilization of solar energy and all-weather heating capabilities, but the current challenges are their preparation processes being time-consuming and equipment expensive. Herein, a simple and facilitated preparation method for the multifunctional wearable heater was developed, which springs Ag nanoparticles on the shish-kebab superstructure film via deposited melanin-like polydopamine as the adhesive. The light absorption ability of the resultant wearable heater in the visible region can be significantly enhanced by the addition of polydopamine, realizing a highly efficient photothermal conversion ability. Accordingly, it can achieve rapid warming ability whether passive heating (up to 45 °C about 60 s at 100 mW/cm2) or active heating (up to 72 °C about 40 s at 0.6 V), compared to ordinary cotton fabric. In addition, it can realize a 6.3 °C temperature difference with Cotton, showing excellent heat preservation ability. This study demonstrates a simple and low-cost approach for the prepared shish-kebab superstructure-based wearable heaters.

Multifunctional Oxidized Dextran-Metformin as a Tissue-Adhesive Hydrogel to Prevent Postoperative Peritoneal Adhesions in Patients with Metabolic Syndrome.

Patients with metabolic syndrome (MetS) undergoing surgery are at high risk of developing peritoneal adhesions and other severe postoperative complications. However, the single shielding function and absence of physiological activity render conventional methods less useful in preventing adhesions in patients with MetS. To address this challenge, a convenient method is introduced for developing a novel tissue-adhesive hydrogel called oxidized dextran-metformin (ODE-ME) via Schiff base linkages. This injectable ODE-ME hydrogel exhibits excellent tissue-adhesive properties and various physiological functions, particularly enhanced antibacterial effects. Furthermore, in vivo experiments demonstrate that the hydrogel can effectively alleviate hyperglycemia, reduce excessive inflammation, and improve fibrinolytic activity in MetS mice, thereby preventing adhesions and promoting incisional healing. The hydrogel concurrently isolates injured tissues and lowers the blood glucose levels immediately after surgery in mice. Therefore, the ODE-ME hydrogel functions as a multifunctional barrier material and has potential for preventing postoperative peritoneal adhesions in patients with MetS in clinical settings.

Reinforcing and toughening bacterial cellulose/MXene films assisted by interfacial multiple cross-linking for electromagnetic interference shielding and photothermal response.

Ultrathin MXene composite films, with their flexibility, metal-level conductivity, and multifunction compatibility, are an ideal choice for electromagnetic interference (EMI) shielding materials in future developments. Nonetheless, the dilemma between electrical conductivity and robustness in these composite films remains a challenge. Herein, an ammonium polyphosphate (APP) assisted interfacial multiple cross-linking strategy, achieved via simple solution blending and filtration, was employed to reinforce and toughen the "brick-mortar" layered MXene/bacterial cellulose (MBCA) films without compromising their conductivity and EMI shielding ability. The introduction of a small amount of APP leads to multiple interfacial interactions between MXene and bacterial cellulose, resulting in significant enhancements in mechanical strength (360.8 MPa), Young's modulus (2.8 GPa), fracture strain (17.3%), and toughness (34.1 MJ/m3). Concurrently, the MBCA film displayed satisfactory conductivity values of 306.7 S/cm and an EMI SE value of 41 dB upon optimizing the MXene content. Additionally, the MBCA film demonstrated a consistent, rapid-response photothermal conversion capability, achieving a photothermal conversion temperature of 97 °C under a light intensity of 200 mW/m2. Consequently, this tough and multifunctional EMI shielding film holds substantial promise for protecting electronic equipment.

Controllable-morphology polymer blend photonic metafoam for radiative cooling.

Incorporating radiative cooling photonic structures into the cooling systems of buildings presents a novel strategy to mitigate global warming and boost global carbon neutrality. Photonic structures with excellent solar reflection and thermal emission can be obtained by a rational combination of different materials. The current preparation strategies of radiative cooling materials are dominated by doping inorganic micro-nano particles into polymers, which usually possess insufficient solar reflectance. Here, a porous polymer metafoam was prepared with polycarbonate (PC) and polydimethylsiloxane (PDMS) using a simple thermally induced phase separation method. The metafoam exhibits strong solar reflectivity (97%), superior thermal emissivity (91%), and low thermal conductivity (46 mW m-1 K-1) due to the controllable morphology of the randomly dispersed light-scattering air voids. Cooling tests demonstrate that the metafoam could reduce the average temperature by 5.2 °C and 10.2 °C during the daytime and nighttime, respectively. In addition, the simulation of a cooling energy system of buildings indicates that the metafoam can save 3.2-26.7 MJ m-2 per year in different cities, which is an energy-saving percentage of 14.7-41%. The excellent comprehensive performances, including the passive cooling property, thermal insulation and self-cleaning of the metafoam makes it appropriate for practical outdoor applications, exhibiting its great potential as an energy-saving building cooling material.

The Study on the Morphology and Compression Properties of Microcellular TPU/Nanoclay Tissue Scaffolds for Potential Tissue Engineering Applications.

Thermoplastic polyurethane (TPU) materials have shown promise in tissue engineering applications due to their mechanical properties and biocompatibility. However, the addition of nanoclays to TPU can further enhance its properties. In this study, the effects of nanoclays on the microstructure, mechanical behavior, cytocompatibility, and proliferation of TPU/nanoclay (TPUNC) composite scaffolds were comprehensively investigated. The dispersion morphology of nanoclays within the TPU matrix was examined using transmission electron microscopy (TEM). It was found that the nanoclays exhibited a well-dispersed and intercalated structure, which contributed to the improved mechanical properties of the TPUNC scaffolds. Mechanical testing revealed that the addition of nanoclays significantly enhanced the compressive strength and elastic resilience of the TPUNC scaffolds. Cell viability and proliferation assays were conducted using MG63 cells cultured on the TPUNC scaffolds. The incorporation of nanoclays did not adversely affect cell viability, as evidenced by the comparable cell numbers between nanoclay-filled and unfilled TPU scaffolds. The presence of nanoclays within the TPUNC scaffolds did not disrupt cell adhesion or proliferation. The incorporation of nanoclays improved the dispersion morphology, enhanced mechanical performance, and maintained excellent biocompatibility. These findings suggest that TPUNC composites have great potential for tissue engineering applications, providing a versatile and promising scaffold material for regenerative medicine.

Phase morphology, rheological behavior and mechanical properties of supertough biobased poly(lactic acid) reactive ternary blends.

Poly(lactic acid) (PLA) is one of the most promising bio-based polyester with great potential to replace for the petroleum-based polymers, which can significantly reduce greenhouse gas emissions. However, the inherent brittleness of PLA seriously restricts its broad applications. Herein, PLA/poly(ε-caprolactone) (PCL)/ethylene methyl acrylate-glycidyl methacrylate (EMA-GMA) ternary blends with different phase structures were prepared through reactive blending. The reactions between the epoxy groups of EMA-GMA and the carboxyl and hydroxyl end groups of PLA and PCL and were evidenced from the Fourier transform infrared spectroscopy, dynamic mechanical analysis and rheological results. The atomic force microscopy (AFM) images clearly revealed the formation of stack structure of the PCL and EMA-GMA minor phases in PLA/PCL/EMA-GMA (80/15/5) blend, and core-shell particle structures in PLA/PCL/EMA-GMA (80/10/10) and (80/5/15) blends. In terms of elongation at break and impact toughness, PLA/PCL/EMA-GMA (80/5/15) blend presents the best properties among all the compositions. Moreover, it also behaved excellent stiffness-toughness balance. The toughening mechanism can be ascribed to the formation of core-shell structure and the existence of interfacial adhesion in the ternary blends. This work can provide guide for the preparation and design of PLA-based partially renewable supertough materials that can compete with conventional petro-derived plastics.

Mushroom-mimetic 3D hierarchical architecture-based e-skin with high sensitivity and a wide sensing range for intelligent perception.

Electronic skin (e-skin) is one of the most important components of future wearable electronic devices, whose sensing performances can be improved by constructing micropatterns on its sensitive layer. However, in traditional e-skins it is difficult to balance sensitivity and the pressure sensing range, and most micropatterns are generally prepared by some complex technologies. Herein, mushroom-mimetic micropatterns with 3D hierarchical architecture and an interdigital electrode are facilely prepared. The micropatterned sensitive layer is further developed through spraying carbon nanotube (CNT) dispersion on the thermoplastic polyurethane (TPU) film with mushroom-mimetic micropatterns (denoted as MMTC). Thanks to the "interlocking effect" between mushroom-mimetic micropatterns and the interdigital electrode in the as-prepared MMTC/interdigital electrode e-skin, the e-skin exhibits a high sensitivity (up to 600 kPa-1), a wide pressure sensing range (up to 150 kPa), a short response time (<20 ms) and excellent durability (15 000 cycles). The MMTC/interdigital electrode e-skin is capable of precisely monitoring health conditions via the as-acquired physiological parameters in real time. Moreover, such e-skins can be used to monitor gestures wirelessly, sense the trajectory of pressure stimuli and recognize Morse code under water. This study provides a cost-efficient, facile strategy to design e-skin for future-oriented wearable intelligent systems.

Melt stretching and quenching produce low-crystalline biodegradable poly(lactic acid) filled with ß-form shish for highly improved mechanical toughness.

High-toughness biodegradable poly(lactic acid) (PLA) has always been intensively pursued on the way of replacing traditional petroleum-based plastics. Regulating microstructures to achieve self-toughening holds great promise due to avoidance of incorporating other heterogeneous components. Herein, we propose a straightforward and effective way to tailor microstructures and properties of PLA through melt-stretching and quenching of slightly crosslinked samples. The melt stretching drives chains orientation and crystallization at high temperature, while the quenching followed can freeze the crystallization process to any stage. For the first time, we prepare a type of transparent and low-crystalline PLA filled with rod-like ß-form shish, which displays an outstanding tensile toughness, almost 17 times that of the conventional technique-processed one. This mechanical superiority is enabled by an integration of high ductility due to oriented chain network, and high tensile stress endowed by nanofibrous filler's role of ß-form shish. Furthermore, the mechanically toughened PLA is demonstrated to generate the richest micro-cracks and shear bands under loading, which can effectively dissipate the deformational energy and underlie the high toughness. This work opens a new prospect for the bottom-up design of high-performance bio-based PLA materials that are tough, ductile and transparent by precise microstructural regulation through scalable melt processing route.

A Multifunctional Asymmetric Fabric for Sustained Electricity Generation from Multiple Sources and Simultaneous Solar Steam Generation.

Harvesting electrical energy from water and moisture has emerged as a novel ecofriendly energy conversion technology. Herein, a multifunctional asymmetric polyaniline/carbon nanotubes/poly(vinyl alcohol) (APCP) that can produce electric energy from both saline water and moisture and generate fresh water simultaneously is developed. The constructed APCP possesses a negatively charged porous structure that allows continuous generation of protons and ion diffusion through the material, and a hydrophilicity-hydrophobic interface which results in a constant potential difference and sustainable output. A single APCP can maintain stable output for over 130 h and preserve a high voltage of 0.61 V, current of 81 µA, and power density of 82.4 µW cm-3 with 0.15 cm3 unit size in the water-induced electricity generation process. When harvesting moisture energy, the APCP creates dry-wet asymmetries and triggers the spontaneous development of electrical double layer with a current density of 1.25 mA cm-3 , sufficient to power small electronics. A device consisting of four APCP can generate stable electricity of 3.35 V and produce clean water with an evaporation rate of 2.06 kg m-2  h-1 simultaneously. This work provides insights into the fabrication of multifunctional fabrics for multisource energy harvesting and simultaneous solar steam generation.

Multifunctional magnetic sponge with outstanding solar/electro-thermal performance for high-efficiency and all-day continuous cleanup of crude oil spills.

The high-efficient, eco-friendly and low-energy cleanup of viscous crude oil spills is still a global challenge. Emerging absorbents with self-heating function are promising candidates due to that they can significantly decrease crude oil viscosity via in-situ heat transfer so as to accelerate remediation. Herein we developed a novel multifunctional magnetic sponge (P-MXene/Fe3O4@MS) with outstanding solar/electro-thermal performance by facilely coating Ti3C2TX MXene, nano-Fe3O4 and polydimethylsiloxane onto melamine sponge for fast crude oil recovery. Superior hydrophobicity (water contact angle of 147°) and magnetic responsivity allowed P-MXene/Fe3O4@MS to be magnetically driven for oil/water separation and easy recycling. Owing to excellent full-solar-spectrum absorption (average absorptivity of 96.5 %), effective photothermal conversion and high conductivity (resistance of 300 Ω), P-MXene/Fe3O4@MS possessed remarkable solar/Joule heating capability. The maximum surface temperature of P-MXene/Fe3O4@MS could quickly reach 84 °C under a solar irradiation of 1.0 kW/m2 and 100 °C after applying a voltage of 20 V. The generated heat induced a significant decrease of crude oil viscosity, enabling the composite sponge to absorb more than 27 times its weight of crude oil within 2 min (1.0 kW/m2 irradiation). More importantly, by means of the synergistic effect of Joule heating and solar heating, a pump-assisted absorption device based on P-MXene/Fe3O4@MS was able to realize the high-efficiency and all-day continuous separation of high-viscosity oil on water surface (crude oil flux = 710 kg m-2 h-1). The new-typed multifunctional sponge provides a competitive approach for dealing with large-area crude oil pollution.

Surface Modification of Super Arborized Silica for Flexible and Wearable Ultrafast-Response Strain Sensors with Low Hysteresis.

Conductive hydrogels exhibit high potential in the fields of wearable sensors, healthcare monitoring, and e-skins. However, it remains a huge challenge to integrate high elasticity, low hysteresis, and excellent stretch-ability in physical crosslinking hydrogels. This study reports the synthesis of polyacrylamide (PAM)-3-(trimethoxysilyl) propyl methacrylate-grafted super arborized silica nanoparticle (TSASN)-lithium chloride (LiCl) hydrogel sensors with high elasticity, low hysteresis, and excellent electrical conductivity. The introduction of TSASN enhances the mechanical strength and reversible resilience of the PAM-TSASN-LiCl hydrogels by chain entanglement and interfacial chemical bonding, and provides stress-transfer centers for external-force diffusion. These hydrogels show outstanding mechanical strength (a tensile stress of 80-120 kPa, elongation at break of 900-1400%, and dissipated energy of 0.8-9.6 kJ m-3 ), and can withstand multiple mechanical cycles. LiCl addition enables the PAM-TSASN-LiCl hydrogels to exhibit excellent electrical properties with an outstanding sensing performance (gauge factor = 4.5), with rapid response (210 ms) within a wide strain-sensing range (1-800%). These PAM-TSASN-LiCl hydrogel sensors can detect various human-body movements for prolonged durations of time, and generate stable and reliable output signals. The hydrogels fabricated with high stretch-ability, low hysteresis, and reversible resilience, can be used as flexible wearable sensors.

Highly stable lithium sulfur batteries enhanced by flocculation and solidification of soluble polysulfides in routine ether electrolyte.

Lithium-sulfur batteries (LSBs) are among the most promising next-generation high energy density energy-storage systems. However, practical application has been hindered by fundamental problems, especially shuttling by the higher-order polysulfides (PSs) and slow redox kinetics. Herein, a novel electrolyte-based strategy is proposed by adding an ultrasmall amount of the low-cost and commercially available cationic antistatic agent octadecyl dimethyl hydroxyethyl quaternary ammonium nitrate (SN) into a routine ether electrolyte. Due to the strong cation-anion interaction and bridge-bonding with SN, rapid flocculation of the soluble polysulfide intermediates into solid-state polysulfide-SN sediments is found, which significantly inhibited the adverse shuttling effect. Moreover, a catalytic effect was also demonstrated for conversion of the polysulfide-SN intermediates, which enhanced the redox kinetics of Li-S batteries. Encouragingly, for cells with only 0.1 % added SN, an initial specific capacity of 783.6 mAh/g and a retained specific capacity of 565.7 mAh/g were found at 2C after 200 cycles, which corresponded to an ultralow capacity decay rate of only 0.014 % per cycle. This work may provide a simple and promising regulation strategy for preparing highly stable Li-S batteries.

Hyphenated DEMS and ATR-SEIRAS techniques for in situ multidimensional analysis of lithium-ion batteries and beyond.

A wide spectrum of state-of-the-art characterization techniques have been devised to monitor the electrode-electrolyte interface that dictates the performance of electrochemical devices. However, coupling multiple characterization techniques to realize in situ multidimensional analysis of electrochemical interfaces remains a challenge. Herein, we presented a hyphenated differential electrochemical mass spectrometry and attenuated total reflection surface enhanced infrared absorption spectroscopy analytical method via a specially designed electrochemical cell that enables a simultaneous detection of deposited and volatile interface species under electrochemical reaction conditions, especially suitable for non-aqueous, electrolyte-based energy devices. As a proof of concept, we demonstrated the capability of the homemade setup and obtained the valuable reaction mechanisms, by taking the tantalizing reactions in non-aqueous lithium-ion batteries (i.e., oxidation and reduction processes of carbonate-based electrolytes on Li1+xNi0.8Mn0.1Co0.1O2 and graphite surfaces) and lithium-oxygen batteries (i.e., reversibility of the oxygen reaction) as model reactions. Overall, we believe that the coupled and complementary techniques reported here will provide important insights into the interfacial electrochemistry of energy storage materials (i.e., in situ, multi-dimensional information in one single experiment) and generate much interest in the electrochemistry community and beyond.

Ultrafine aramid nanofibers prepared by high-efficiency wet ball-milling-assisted deprotonation for high-performance nanopaper.

Aramid nanofibers (ANFs) with a nanoscale diameter, large aspect ratio, and exposed electronegative surface, as well as ultrahigh thermal/chemical inertness and extreme mechanical properties, provide promising applications in many emerging fields, but these are greatly limited by the low preparation efficiency and broad diameter distribution. Herein, we put forward a high-efficiency wet ball milling-assisted deprotonation (BMAD) strategy to rapidly prepare ANFs with an ultrafine diameter. The strong shear and collision forces from ball-milling induced stripping and splitting effects on the macroscopic fibers, which promoted the penetration and expanded the contact interfaces between reactants, thus accelerating the deprotonation reaction and refining the ANF diameter. As a result, ultrafine ANFs with a diameter of only 2.09 nm and high concentration (1 wt%) were successfully achieved within 30 min. This BMAD strategy represents a vastly advantageous approach compared to the existing reported ANF preparation approaches in terms of efficiency (20 g L-1 h-1) and fiber diameter. The ultrafine microstructure leads to the corresponding ANF nanopaper having more compact stacking and fewer defects, thus exhibiting extraordinary mechanical properties including tensile strength (271.7 MPa) and toughness (33.1 MJ m-3). This work achieves significant progress toward high-efficiency production of ultrafine ANFs, bringing about appreciable prospects in preparing promising multifunctional ANF-based materials.

Contact Engineering of Halide Perovskites: Gold is Not Good Enough; Metalloid is Better.

The operation stability of halide perovskite devices is the critical issue that impedes their commercialization. The main reasons are that the ambient H2 O molecules can easily deteriorate the perovskites, while the metal electrodes react in different degrees with the perovskites. Herein, one kind of new electrode, the metalloids, is reported, which are much more stable than the conventional noble metals as electrical contacts for halide perovskites. The degradation mechanism of halide perovskites with noble metal electrodes is carefully studied and compared with the metalloid electrodes. It is found that the iodide ions can easily halogenate Cu and Ag in halide perovskites. Although Au is almost not halogenated, it can also decompose the perovskite film. On the contrary, after long-term storage, the metalloid electrodes remain intact on the perovskite film without any degradation. In addition, the long-time operation stability of the perovskite devices with metalloid electrodes is much higher than that of noble metals. First-principles calculations confirm the exceptional stability of the metalloid electrodes.This work explores the ultra-stable electrodes for halide perovskites, paving the way to the large-scale deployment of perovskite-based electronic devices.