Snake Scale-Inspired Poly(vinylidene fluoride)/Ti3CNTx@Polypyrrole Coatings for Ultrawide-Bandwidth Microwave and Visible Light Absorption.

The accuracy of data collected by optical instruments can be greatly impacted by radar band electromagnetic waves (EM) and scattered visible light. Traditional electromagnetic-wave-absorbing (EMA) materials face challenges in effectively attenuating electromagnetic waves within the visible light spectrum. To address this issue, a structural engineering-based assembly strategy was developed to construct PVDF/Ti3CNTx@PPyNF composites with multiple heterogeneous interfaces, inspired by snake scales. And through the self-doping of N elements and the coating process, the material finally exhibits excellent microwave and visible light absorption properties. This approach generates multiple polarization losses of electromagnetic waves, enabling the material to exhibit excellent electromagnetic wave absorption performance. Specifically, the PVDF/Ti3CNTx@PPyNF composite, containing 5 wt % Ti3CNTx@PPyNFs, demonstrates exceptional microwave absorption performance, with a minimum reflection loss of -65.5 dB and an effective absorption bandwidth of up to 6.95 GHz. Additionally, the composite coating exhibits 97.4% visible light absorption performance, providing a promising solution to the challenges of protecting against complex electromagnetic environments.

All-Organic Hyper-Crosslinked Polymer/Polyimide Composite Films with Ultralow High-Frequency Dielectric Constant.

The ever increasing demand for high-speed communication at high frequency promotes the rapid development of low-dielectric polymer films. Aromatic polyimide (PI) has been widely used as the main dielectrics in the flexible circuit board due to its excellent dielectric, mechanical, and thermal properties. Nevertheless, the dielectric constant of PI films at a high frequency range (several GHz) is relatively high and cannot satisfy the requirement of high-frequency communication. On this basis, a hyper-crosslinked polymer (HCP) and fabricated all-organic HCP/PI composite films through a physical blending method is synthesized. The porous structure of HCP is helpful to reduce the dielectric constant of PI matrix. The effects of HCP loadings on the dielectric, mechanical, and thermal properties of HCP/PI composite films are systematically investigated. The dielectric constants of the composite films can be reduced to 1.6-1.8 in the frequency range of 8.2-9.6 GHz when the HCP content reached 10 wt.%. The proposed method in this work is simple and effective to reduce the dielectric constant of PI and can be easily extended to other organic component-filled PI systems.

Development of wrinkled reduced graphene oxide wrapped polymer-derived carbon microspheres as viable microwave absorbents via a charge-driven self-assembly strategy.

It is widely recognized that designing a special micro/nanostructure of microwave absorption materials for enhancing interface polarization benefits dielectric loss capability. In this work, a facile charge-driven self-assembly strategy is reported to prepare wrinkled reduced graphene oxide wrapped polymer-derived carbon (CS@rGO) microspheres. Noticeably, the unique three-dimensional (3D) multi-interface structure imparts CS@rGO microspheres with promoted microwave absorption capability. Adjusting the charge-driven self-assembly cycle times, the dielectric properties and impedance matching characteristics of the CS@rGO microspheres can be optimized. The minimum reflection loss (RLmin) of the sample can reach up to -55.24 dB at 13.75 GHz and the effective absorption bandwidth (RL ≤ -10 dB) is 4.30 GHz (11.55-15.85 GHz) at only a thickness of 1.85 mm. This research provides a pathway to explore the high-performance microwave absorber through the construction of the unique 3D multi-interface structure.

Graphene fibre film/polydimethylsiloxane nanocomposites for high-performance electromagnetic interference shielding.

Exploration of high-performance electromagnetic interference (EMI) shielding materials has become a trend to address the increasing electromagnetic (EM) wave pollution environment. In this paper, oriented graphene fibre film (GFF)/polydimethylsiloxane (PDMS) nanocomposites with one-ply unidirectional, two-ply cross-ply, and two-ply unidirectional configurations were prepared using wet-spinning and hot-pressing techniques in a two-step process. Due to the anisotropic electrical performance of GFF, the one-ply laminate exhibits EMI shielding anisotropy that is affected by fibre orientation relative to the electric field component in EM waves. The maximum shielding difference at 8.8 GHz is up to 32.0 dB between the fibre orientation parallel to and perpendicular to the electric field component. In addition, we found that adding a layer of GFF is an intuitive method to enhance the shielding efficiency (SE) of GFF/PDMS nanocomposites by providing more interfaces to enhance absorption losses. An optimal EMI shielding performance of a two-ply unidirectional laminate is observed with an SE value of 50.6 dB, which shields 99.999% of EM waves. The shielding mechanisms are also discussed and clarified from the results of both experimental and theoretical analyses by adjusting the GFF structural parameters, such as the fibre orientation, areal density, number of plies and stacking sequence.

Silk-Waste-Derived Porous Carbon for Fast Electric Heating under Safe Voltage.

Fast and safe electric heating is highly needed in extreme climates or thermal therapy. Herein, porous activated carbon derived from silk waste is prepared by a simple method. Various porous activated carbons are obtained using different types and concentrations of activator (KOH, KCl, and KHCO3). The effect of the microstructure on the electric heating performance of these carbons is investigated carefully. The type, activator concentration, and carbonization temperature play key roles in the regulation of electric heating properties. The porous carbon activated by 0.05 M KHCO3 at 800 °C demonstrates larger specific surface area (3077 m2 g-1), higher graphitization degree, and lower resistance (2.4 Ω cm), which synergistically contribute greatly to its higher electrothermal efficiency and better electric heating performance. The equilibrium temperature could reach 73 °C in 2 min under a safe voltage of 12 V, proving the better pore-forming capacity and activating function of KHCO3. An electric heating cotton@carbon composite fabric with quite good electric heating property and stability is also prepared, which could reach 38 °C in 2 min under 12 V safe voltage and maintain a temperature 10 °C higher than the ambient temperature even when bent at an angle of 55°. This activated carbon derived from waste protein using a simple and cheap process has great potential in practical applications.

Discovery of N-(4-(Benzyloxy)-phenyl)-sulfonamide Derivatives as Novel Antagonists of the Human Androgen Receptor Targeting the Activation Function 2.

Androgen receptor (AR) antagonists have been widely used for the treatment of prostate cancer (PCa). As a link between the AR and its transcriptional function, the activation function 2 (AF2) region has recently been revealed as a novel targeting site for developing AR antagonists. Here, we reported a series of N-(4-(benzyloxy)-phenyl)-sulfonamide derivatives as new-scaffold AR antagonists targeting the AR AF2. Therein, compound T1-12 showed excellent AR antagonistic activity (IC50 = 0.47 µM) and peptide displacement activity (IC50 = 18.05 µM). Furthermore, the in vivo LNCaP xenograft study confirmed that T1-12 offered effective inhibition on tumor growth when administered intratumorally. The study represents the first successful attempt to identify a small molecule targeting the AR AF2 with submicromolar AR antagonistic activity by structure-based virtual screening and provides important clues for the development of novel therapeutics for PCa treatment.

Controllable assembly of continuous hollow graphene fibers with robust mechanical performance and multifunctionalities.

Macroscopic conformation of individual graphene sheets serves as the backbone of translating their intrinsic merits towards multifunctional practical applications. However, controllable and continuous assemblies of graphene-based nanomaterials to create stable macroscopic structural components are always in face of great challenge. We have developed a scalable converging-flow assisted wet-spinning methodology for continuously fabricating hollow graphene fibers (HGFs, the newest variation of solid graphene fibers) with high quality. The degradable silk thread is selectively utilized as the continuous hollow structure former that holds the coaxially stacked graphene sheets aligned through the converging-flow modulating process. For the first time, we have created the longest freestanding HGF in length of 2.1 m. The continuous HGFs are in an average diameter of 180µm and with 4-8µm adjustable wall thicknesses. The optimal HGF demonstrates an average tensile strength of 300 MPa and modulus of 2.49 GPa (comparable to typical solid graphene fibers, but the highest among the reported HGFs in literature) and an exceptional failure elongation of 10.8%. Additionally, our continuous HGFs exhibit spontaneous resistive response to thermal and strain stimuli (in form of large deformations and human motions), offering great potential for developing multifunctional sensors. We envision that this work demonstrates an effective and well-controlled macroscopic assembly methodology for the scaled-up mass production of HGFs.

Degradable photo-crosslinked starch-based films with excellent shape memory property.

With the increasingly serious plastic pollution, people's demand for the multi-functional biodegradable plastics is becoming more and more urgent. Inspired by the crosslinked shape memory polymers, the crosslinked starch films were synthesized by inducing the decomposition of benzophenone into free radical and depriving hydrogen on starch macromolecules under UV irradiation, in order to gain a high shape memory performance. The results showed that a three-dimensional crosslinking network between starch macromolecule chains was formed. Compared with the uncrosslinked starch films, the photo-crosslinked films not only had higher mechanical property (tensile strength increased by 154%), but also had better water resistance (water contact angle from 60° to 87°) due to the reduction of free hydroxyl groups. In addition, the stable covalent bonds serving as netpoints endow photo-crosslinked films with great improvement in shape memory property, with nearly 180° bending recovery. More importantly, the maximum shape memory fixity ratio (Rf) and shape memory recovery ratio (Rr) under stretch deformation were 96.5% and 99.8%, respectively. And the Rf and Rr could reach 94.6% and 79.8% even at higher strain. In all, the excellent shape memory performance and good degradability crosslinked starch films, which have great potential application in disposable heat-shrinkable packaging materials.

Ti3C2Tx/PEDOT:PSS Composite Interface Enables over 17% Efficiency Non-fullerene Organic Solar Cells.

Metal carbide Ti3C2Tx as a new two-dimensional material with excellent metallic conductivity, good water solubility, and superior transmittance in the visible light range shows great potential for applications in optoelectronic devices. Herein, Ti3C2Tx/PEDOT:PSS composite films were fabricated by a simple solution process and employed as an anode interfacial layer in organic solar cells. By introducing the Ti3C2Tx/PEDOT:PSS composite interface into the devices, the highest power conversion efficiency (PCE) of 17.26% was achieved while using PM6:Y6 as the active layer, with a high short-circuit current (Jsc) of 26.52 mA/cm2 and a fill factor of up to 0.76. The PCE is much higher than 15.89% for the pure PEDOT:PSS interfacial layer-based device without doping. The dramatically improved performance was attributed to the increased conductivity of the Ti3C2Tx/PEDOT:PSS composite interface and the increased charge extraction and collection efficiency of the devices. This work presents an effective method to prepare the Ti3C2Tx/PEDOT:PSS composite interface and high-performance organic solar cells.

Enhanced Thermal Insulation of the Hollow Glass Microsphere/Glass Fiber Fabric Textile Composite Material.

Glass fiber fabrics/hollow glass microspheres (HGM)-waterborne polyurethane (WPU) textile composites were prepared using glass fiber, WPU, and HGM as skeleton material, binder, and insulation filler, respectively, to study the effect of HGM on the thermal insulation performance of glass fiber fabrics. Scanning electron microscopy, Instron 3367 tensile test instrument, thermal constant analysis, and infrared thermal imaging were used to determine the cross-sectional morphology, mechanical property, thermal conductivity, and thermal insulation property, respectively, of the developed materials. The results show that the addition of HGM mixed in WPU significantly enhanced thermal insulation performance of the textile composite with the reduction of thermal conductivity of 45.2% when the volume ratio of HGM to WPU is 0.8 compared with that of material without HGM. The composite can achieve the thermal insulation effect with a temperature difference of 17.74 °C at the temperature field of 70 °C. Meanwhile, the tensile strength of the composite is improved from 14.16 to 22.14 MPa. With these results, it is confirmed that designing hollow glass microspheres (HGM) is an effective way to develop and enhance the high performance of insulation materials with an obvious lightweight of the bulk density reaching about 50%.

Self-Repairing, Large Linear Working Range Shape Memory Carbon Nanotubes/Ethylene Vinyl Acetate Fiber Strain Sensor for Human Movement Monitoring.

Flexible strain sensors have shown great application value in wearable devices. In the past decades, researchers have spent numerous efforts on developing high-stretchability, excellent dynamic durability, and large linear working range flexible strain sensors and shaped a series of important research results. However, the viscoelasticity of the elastic polymer is always a big challenge to develop a flexible sensor. Here, to overcome this challenge, we developed a novel self-repairing carbon nanotubes/ethylene vinyl acetate (CNTs/EVA) fiber strain sensor prepared by embedding the CNTs on the surface of the swollen shape memory EVA fiber via the ultrasonic method. The CNTs/EVA fiber strain sensors responded with significant results, with high stretchability (190% strain), large linear working range (up to 88% strain), excellent dynamic durability (5000 cycles), and fast response speed (312 ms). In addition, the permanently damaged conductive network of the strain sensors, caused by the viscoelasticity of elastic polymer, can restore above the transforming temperature of the shape memory CNTs/EVA fiber. Moreover, the performance of the restored strain sensors was almost as same as that of the original strain sensors. Furthermore, human health monitoring tests show that the CNTs/EVA fiber has a broad application prospect for human health monitoring in wearable electronic devices.

Dual-Mode Carbon Aerogel/Iron Rubber Sensor.

Nowadays, the integration of easy production, simple structure, high sensitivity, and multifunctionality is the developing tendency for flexible sensors. Herein we report a facile manufacture of a highly flexible, sensitive, and multifunctional dual-mode sensor with an ultrasimple structure by directly attaching magnetic iron rubber (IR) onto the surface of carbon aerogel (CA) derived from melamine foam. The dual-mode CA/IR sensor exhibits high sensitivities of 5.6 kPa-1 and 1.6·10-3 Oe-1, respectively, toward pressure and magnetic field in a wide frequency ranging from 0.1 to 10 Hz, which are higher than those of the existing flexible pressure/magnetism sensors. The multifunctionality of the dual-mode CA/IR sensor is demonstrated by monitoring blood pulse, human breath, balloon volume, and thoracic volume via pressure and magnetism sensing or their combination. Due to its simple structure and high sensitivities, the dual-mode sensor is employed as the building block to create a direction-recognizable sensor for identifying the directions of pressure and magnetic field for the awareness of surrounding barriers that are of practical importance in sophisticated situations such as autonomous artificial intelligence, autodriving and robotics, and so on.

Design of Ethylene-Vinyl Acetate Copolymer Fiber with Two-Way Shape Memory Effect.

One-dimensional shape memory polymer fibers (SMPFs) have obvious advantages in mechanical properties, dispersion properties, and weavability. In this work, a method for fabricating semi-crystallization ethylene-vinyl acetate copolymer (EVA) fiber with two-way shape memory effect by melt spinning and ultraviolet (UV) curing was developed. Here, the effect of crosslink density on its performance was systematically analyzed by gel fraction measurement, tensile tests, DSC, and TMA analysis. The results showed that the crosslink density and shape memory properties of EVA fiber could be facilely adjusted by controlling UV curing time. The resulting EVA fiber with cylindrical structure had a diameter of 261.86 ± 13.07 µm, and its mechanical strength and elongation at break were 64.46 MPa and 114.33%, respectively. The critical impact of the crosslink density and applied constant stress on the two-way shape memory effect were analyzed. Moreover, the single EVA fiber could lift more than 143 times its own weight and achieve 9% reversible actuation strain. The reversible actuation capability was significantly enhanced by a simple winding design of the single EVA fiber, which provided great potential applications in smart textiles, flexible actuators, and artificial muscles.

Interfacial Adhesion and Mechanical Properties of PET Fabric/PVC Composites Enhanced by SiO2/Tributyl Citrate Hybrid Sizing.

Poly(ethylene terephthalate) (PET) fabric-reinforced polyvinyl chloride (PVC) composites have a wide range of applications, but the interface bonding of PET fabric/PVC composites has remained a challenge. In this work, a new in-situ SiO2/tributyl citrate sizing agent was synthesized according to the principle of "similar compatibility." The developed sizing agent was used as a PET surface modifier to enhance the interfacial performance of PET fabric/PVC composites. The morphology and structure of the PET filaments, the wettability and tensile properties of the PET fabric, the interfacial adhesion, and the tensile and tearing properties of the PET fabric/PVC composites were investigated. Experimental results showed that many SiO2 nanoparticles were scattered on the surface of the modified PET filaments. Moreover, the surface roughness of the modified PET filaments remarkably increased in comparison with that of the untreated PET filaments. The contact angle of the modified PET filaments was also smaller than that of the untreated ones. The peeling strength of the modified PET fabrics/PVC composites was 0.663 N/mm, which increased by 62.50% in comparison with the peeling strength of the untreated ones (0.408 N/mm). This work provides a new approach to the surface modification of PET and improves the properties of PET fabric/PVC composites.

Author Correction: Ultra-thin enzymatic liquid membrane for CO2 separation and capture.

The original version of this Article contained an error in the spelling of the author Stanley S. Chou, which was incorrectly given as Stan Chou. This has now been corrected in both the PDF and HTML versions of the Article.

Ultra-thin enzymatic liquid membrane for CO2 separation and capture.

The limited flux and selectivities of current carbon dioxide membranes and the high costs associated with conventional absorption-based CO2 sequestration call for alternative CO2 separation approaches. Here we describe an enzymatically active, ultra-thin, biomimetic membrane enabling CO2 capture and separation under ambient pressure and temperature conditions. The membrane comprises a ~18-nm-thick close-packed array of 8 nm diameter hydrophilic pores that stabilize water by capillary condensation and precisely accommodate the metalloenzyme carbonic anhydrase (CA). CA catalyzes the rapid interconversion of CO2 and water into carbonic acid. By minimizing diffusional constraints, stabilizing and concentrating CA within the nanopore array to a concentration 10× greater than achievable in solution, our enzymatic liquid membrane separates CO2 at room temperature and atmospheric pressure at a rate of 2600 GPU with CO2/N2 and CO2/H2 selectivities as high as 788 and 1500, respectively, the highest combined flux and selectivity yet reported for ambient condition operation.

Correction: Flexible composite film of aligned polyaniline grown on the surface of magnetic barium titanate/polyvinylidene fluoride for exceptional microwave absorption performance.

[This corrects the article DOI: 10.1039/C7RA05744J.].

High-Performance Porous Molybdenum Oxynitride Based Fiber Supercapacitors.

Scalable manufacturing of flexible, fiber-shaped energy-storage devices has enabled great technological advances in wearable and portable technology. Replacing inefficient oxides with inexpensive and high-performance oxynitrides with more favorable three-dimensional (3D) structures is critical if the practical applications of these technologies are to be realized. Here, we developed a facile and controllable approach for the synthesis of 3D porous micropillars of molybdenum oxynitride (MON), which exhibit high conductivity, robust stability, and excellent energy-storage properties. Our fiber electrode, containing a 3D hierarchical MON-based anode, yields remarkable linear and areal specific capacitances of 64.8 mF cm-1 and 736.6 mF cm-2, respectively, at a scan rate of 10 mV s-1. Moreover, a wearable asymmetric supercapacitor based on TiN/MON//TiN/MnO2 demonstrates good cycling stability with a linear capacitance of 12.7 mF cm-1 at a scan rate of 10 mV s-1. These remarkable electrochemical properties are mainly attributed to the synergistic effect between the chemical composition of oxynitride and the robust 3D porous structure composed of interconnected nanocrystalline morphology. The presented strategy for the controllable design and synthesis of novel-oxide-derived functional materials offers prospects in developing portable and wearable electronic devices. We also demonstrate that these fiber supercapacitors can be combined with an organic solar cell to construct a self-powered system for broader applications.

One-dimensional carbon nanotube@barium titanate@polyaniline multiheterostructures for microwave absorbing application.

Multiple-phase nanocomposites filled with carbon nanotubes (CNTs) have been developed for their significant potential in microwave attenuation. The introduction of other phases onto the CNTs to achieve CNT-based heterostructures has been proposed to obtain absorbing materials with enhanced microwave absorption properties and broadband frequency due to their different loss mechanisms. The existence of polyaniline (PANI) as a coating with controllable electrical conductivity can lead to well-matched impedance. In this work, a one-dimensional CNT@BaTiO3@PANI heterostructure composite was fabricated. The fabrication processes involved coating of an acid-modified CNT with BaTiO3 (CNT@BaTiO3) through a sol-gel technique followed by combustion and the formation of CNT@BaTiO3@PANI nanohybrids by in situ polymerization of an aniline monomer in the presence of CNT@BaTiO3, using ammonium persulfate as an oxidant and HCl as a dopant. The as-synthesized CNT@BaTiO3@PANI composites with heterostructures were confirmed by various morphological and structural characterization techniques, as well as conductivity and microwave absorption properties. The measured electromagnetic parameters showed that the CNT@BaTiO3@PANI composites exhibited excellent microwave absorption properties. The minimum reflection loss of the CNT@BaTiO3@PANI composites with 20 wt % loadings in paraffin wax reached -28.9 dB (approximately 99.87% absorption) at 10.7 GHz with a thickness of 3 mm, and a frequency bandwidth less than -20 dB was achieved from 10 to 15 GHz. This work demonstrated that the CNT@BaTiO3@PANI heterostructure composite can be potentially useful in electromagnetic stealth materials, sensors, and electronic devices.

Cavopulmonary support with a microaxial pump for the failing Fontan physiology.

The number of patients with the failing Fontan physiology is increasing. We tested a novel in situ microaxial pump (Impella) to support the failing atrio-pulmonary Fontan circulation in an acute pig model. A Fontan model was established in eight juvenile pigs by connecting the right atrium to the main pulmonary artery after tricuspid valve destruction. The Impella pump was inserted retrograde from the distal main pulmonary artery into the right atrium. Hemodynamics, blood gas, and echocardiographic data were compared among baseline, pure Fontan physiology (10 minutes), and mechanically assisted Fontan physiology (up to 12 hours). The Impella system generated a blood flow of 75-85 ml/kg/minute in six animals, and 55-65 ml/kg/minute in two animals. The mechanically assisted Fontan attained a significantly higher mean blood pressure (39.6 ± 7 vs. 24.7 ± 3.3 mm Hg, p < 0.01), lower central venous pressure (5 ± 2.4 vs. 12.8 ± 1.7 mm Hg, p < 0.01), and higher mixed venous saturation (60.4 ± 10.8 vs. 23.4 ± 8.4 mm Hg, p < 0.01) compared with pure Fontan physiology. Cardiac output and stroke volume were similar during baseline and mechanically assisted Fontan (p = not significant). This acute pig study demonstrated the feasibility of mechanical circulatory support in the failing Fontan physiology. The in situ microaxial pump maintained cardiac output while increasing blood pressure and reducing venous pressure.