Advanced Composites and Hybrid Materials最新文献

Ceramic aerogels are excellent ultralight-weight thermal insulators yet impractical due to their tendency towards structural degradation at elevated temperatures, under mechanical disturbances, or in humid environments. Here, we present flexible and durable alumina/zirconia fibrous aerogels (AZFA) fabricated using 3D sol–gel electrospinning — a technique enabling in situ formation of 3D fiber assemblies with significantly reduced time consumption and low processing cost compared to most existing methods. Our AZFAs exhibit ultralow density (> 3.4 mg cm⁻³), low thermal conductivity (> 21.6 mW m⁻¹ K⁻¹), excellent fire resistance, while remaining mechanically elastic and flexible at 1300 °C, and thermally stable at 1500 °C. We investigate the underlying structure-thermal conductivity relationships, demonstrating that the macroscopic fiber arrangement dictates the solid-phase thermal conduction, and the mesopores in the fiber effectively trap air thereby decreasing the gas conduction. We show experimentally and theoretically that directional heat transport, i.e., anisotropic thermal conductivity, can be achieved through compressing the fiber network. We further solve the moisture sensitivity problem of common fibrous aerogels through fluorination coating. The resulting material possesses excellent hydrophobicity and self-cleaning properties, which can provide reliable thermal insulation under various conditions, including but not limited to high-temperature conditions in vehicles and aircraft, humid conditions in buildings, and underwater environments for oil pipelines.

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Flexible pressure sensors as wearable electronic devices to monitor human health have attracted significant attention. Herein, a simple and effective carbonization-free method is proposed to prepare a compressible and conductive reduced graphene oxide (rGO)–modified plant fiber sponge (defined as rGO-PFS). The introduced GO can not only coat on the surface of plant fibers, but also form a large amount of aerogel with microcellular structure in the macroporous PFS. After reduction treatment, the rGO-PFS can form a double-continuous conductive network of rGO aerogel. With the improvement of polydimethylsiloxane (PDMS), the rGO-PFS@PDMS composite exhibits outstanding compressibility (up to 60% compression strain), excellent durability (10,000 stable compression cycles at 50% strain), high sensitivity (234.07 kPa⁻¹ in a pressure range of 20 ~ 387.2 Pa), low detection limit (20 Pa), and rapid response time (28 ms) for practical wearable applications.

Graphical Abstract

A compressible and conductive reduced graphene oxide–modified plant fiber sponge is prepared by a simple and effective carbonization-free method. With the improvement of polydimethylsiloxane, the sponge exhibits outstanding compressibility, durability, high sensitivity, low detection limit, and rapid response time for practical wearable applications.

Transition metal-based (M = Fe, Cu, etc.) catalytic systems are generally popular in advanced oxidation processes; however, the difficulty in restoring their active oxidation state, i.e., M^{n +1} → Mⁿ⁺, limits their performance during the degradation of organic pollutants. Here, a novel strategy of constructing an electron-rich center via systematic intercalation of ultrathin-reduced graphene oxide (rGO) sheets into hydroxide-based materials was introduced to accelerate M^{(n +1)}/Mⁿ⁺ redox cycles of transition metal-based (M = Fe, Cu) heterogeneous catalysts (M-Hydroxide/rGO). According to the first-order kinetic model, the fabricated M-Hydroxide/rGO was more reactive than the corresponding hydroxides or rGO during peroxymonosulfate (PMS) activation. The first-order observed degradation rates (k_obs) of 4-chlorophenol (4-CP) were found in the order of Fe-Hydroxide/rGO (k_obs = 0.152 min⁻¹) > Cu-Hydroxide/rGO (k_obs = 0.091 min⁻¹) > Zn-Hydroxide/rGO (k_obs = 0.021 min⁻¹). Moreover, the prepared best Fe-Hydroxide/rGO catalyst exhibited 6–43-fold high pollutant removal reactivity than catalyst precursors (Fe-Hydroxide/NO₃ and rGO), conventional benchmark catalysts (CuO, Co₃O₄, CuOFe₃O₄, and Fe₃O₄), and various Fe³⁺-based co-catalytic systems (such as Fe³⁺/WS₂ and Fe³⁺/MoS₂). The better efficiency was ascribed to the electron-rich domain (C = O, O–C = O) of interlayered rGO, allowing the constant regeneration of Fe²⁺ via efficient electron transfer and the production of diverse reactive species, i.e., sulfate radicals (•SO₄⁻), hydroxyl (•OH) radicals, and singlet oxygen (¹O₂). Moreover, a suitable degradation pathway of 4-CP, passing through diverse reactive species, was proposed. This study highlights the vital role of rGO in improving the activity and stability of Fe-based hydroxide catalysts by accelerating Fe³⁺/Fe²⁺ redox cycle through regular feeding of electrons.

Molecular layer deposition (MLD) offers molecular level control in deposition of organic and hybrid thin films. This article describes a new type of inorganic–organic silicon-based MLD process where Aluminium chloride (AlCl₃) and 1,4-bis(triethoxysilyl)benzene (BTEB) were used as precursors. Hybrid films were deposited at a temperature range of 300 to 500 °C and high growth per cycle (GPC) up to 1.94 Å was obtained. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) were used to analyze the appearance of the film surface. The hybrid film was amorphous in low-magnification FESEM images but some particulates appeared in high-magnification FESEM images (200 k). Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), Time-of-flight elastic recoil detection analysis (ToF-ERDA), and X-ray photoelectron spectroscopy (XPS) were employed to analyze the structure and composition of the hybrid film. The ratio of Al/Si in the hybrid film was 0.8. The storage environment of the films affected their capacitance, dielectric constant, leakage performance, and breakdown voltage. A film stored in a high vacuum (10^–6 mbar) environment had low leakage current density (< 10^–6 A × cm⁻² at an applied voltage of 28 V) and a dielectric constant of 4.94, which was much smaller than after storing in a humid ambient environment.

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In this study, an energy storage multifunctional sandwich structure (ESMS) was designed to perform well-balanced and excellent multifunctional performance. The corrugated core sandwich structure was newly developed to prevent the degradation of mechanical properties even when lithium polymer (LiPo) batteries are integrated. The empty space of the corrugated core was used as an energy storage space, and the corrugated core was fabricated via 3D printing technology using a continuous carbon fiber filament. The energy storage characteristics were implemented using LiPo batteries embedded in the neutral axis of the sandwich structure. The static and fatigue bending properties of the ESMSs were analyzed through a three-point bending (3PB) test. A battery charge/discharge test was performed before and after the mechanical tests to analyze the effect of bending loading on the energy storage properties. The conventional foam-core ESMS showed negative changes in flexural properties such as strength (−27% in Foam-SH) and modulus (−22% in Foam-AD) due to the battery embedding. On the other hand, in the case of the 3D-printed core ESMS, no degradation in mechanical properties was observed even though the energy density was 1.7 times higher than that of the foam-core ESMS. Furthermore, no defects or delamination were found in the battery embedded in the 3D-printed core ESMS, unlike the battery embedded in the foam-core ESMS where delamination between the separator, anode, and cathodes occurred after the 3 PB test. Consequently, a 3D-printed core ESMS with superior balanced multifunctional performance can be implemented without degradation of both the mechanical properties and energy storage characteristics.

Magnesium alloys have recently received much attention as fracturing tools for unconventional oil and gas development. It is well known that increasing micro-galvanic corrosion by doping elements in magnesium alloys is an effective method to get highly degradable alloys. The study aimed to evaluate the effect of different doping elements (i.e., copper, nickel and iron) on the mechanical and degradation behavior of hot extruded magnesium alloys. Nickel-containing alloys show high degradability and mechanical properties compared to the other two alloys. Specifically, the second phase of nickel-containing alloys has a dotted distribution, and this distribution favors the diffusion of corrosion. Meanwhile, the addition of nickel improves the mechanical properties of the alloy with a compressive strength of 430.6 MPa. In addition, based on the first principles and phase diagram simulations. With the addition of nickel, the compounds formed in the alloy act as drivers for the improved degradation properties, resulting in a corrosion rate of 1638.14 mm/year at 93 °C. Therefore, nickel-containing alloys that have been hot extruded show wide application prospects in the field of oil and gas extraction.

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The influence of Cu/Ni/Fe elements on the microstructure, mechanical properties, and corrosion properties of Mg-6Al (wt. %) alloy was investigated using electrochemical tests, hydrogen evolution, and weight loss measurement.

Lignin possesses a number of functional groups including phenolic hydroxyl and methoxy groups, which grant its bioactivity for the fabrication of bio-polymer-based composites in bone tissue engineering applications. However, the heterogeneity of natural lignin limits its use in biomedicine. In the present study, a bio-enzyme approach was proposed to synthesize lignin-dehydrogenated polymers from the precursors of arabinogalactan (DHP-A) and xylose (DHP-X), which possess more homogeneous substructures with appropriate functional groups. Both DHP-A and DHP-X showed excellent in vitro abilities for regulating biocompatibility, “pre-oxidation,” and chondrogenic differentiation, in which DHP-A possessed cartilage repair ability due to its abundant content of phenolic hydroxyl groups (3.00 mmol g⁻¹). Hence, DHP-A was hybridized with hyaluronic acid (HA) to prepare a hydrogel (DHP-HA) composite, which exhibited the compressive strength and modulus of 810 kPa and 310 kPa, respectively. Notably, these properties closely resemble those of articular cartilage, which typically ranges from 320 to 810 kPa. The application of DHP-HA hydrogel composite in a rat cartilage defect model in vivo revealed that it promoted the regeneration of hyaline cartilage rather than hypertrophic cartilage, which could heal 66.22–79.26% of the cartilage defects compared to the control group. Pre-oxidation of DHP-A elicits a mechanism that activates the oxidative stress system, leading to an augmented stress response and consequent increase in stress resistance. This study introduces a pioneering enzymatic synthesis technique to prepare the biologically active lignin for creating bio-polymer-based composites, demonstrating its potential as an innovative avenue for therapeutic cartilage regeneration.

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Bioenzymatically synthesized lignin dehydrogenation polymers to hybridize with hyaluronic acid to prepare hydrogel composites for promoting cartilage defect repair.

Designing advanced functional electrode materials with a tunable structure and multiphase/composition comprising a single metal via a one-step synthesis process for supercapacitor applications is challenging. Here, a dual-phase cobalt sulfide/cobalt oxyhydroxide (Co_1-xS/HCoO₂) hexagonal nanostructure on iron metal-organic framework (MIL-88A) derived iron carbide (Fe₃C) integrated porous carbon nanofibers (PCNFs) is synthesized using a wet-chemical curing technique. MIL-88A is integrated by a physical blending process into a PAN/PMMA polymer matrix during the PCNFs preparation process. The integrated MIL-88A-derived iron carbide nanomaterial contributes to improving the electrochemical performance of electrode materials by lowering the inherent resistance. The optimal (Co_1-xS/HCoO₂)-1@Fe₃C/PCNFs electrode exhibits a high specific capacitance of 1724 F g⁻¹ at 1 A g⁻¹ with an improved rate capability and exceptional cycling stability with 89.8% retention even after 10,000 cycles. These excellent electrochemical capabilities are predominantly attributed to the double-phase hybrid composites, which have a variety of abundant sites, a large active surface area, rapid electron and ion transport capability, and strong structural stability. A Co_1-xS/HCoO₂-1@Fe₃C/PCNFs//Fe₂O₃/NPC@PCNFs asymmetric supercapacitor (ASC) demonstrates excellent electrochemical energy storage behavior, with a maximum energy density of 65.68 Wh kg⁻¹ at a power density of 752.7 W kg⁻¹ and excellent cycling stability (90.3% capacitance retention after 10,000 charge-discharge cycles at a constant current density of 20 A g⁻¹). These electrochemical results indicate that this ASC outperforms previously reported asymmetric supercapacitors, showing that the heterophasic electrode (Co_1-xS/HCoO₂)-1@Fe₃C/PCNFs has the potential to be applied in supercapacitor devices.

Albeit the abundance, renewability, and biodegradability of the polymer known as cellulose, the insolubility and poor dispersibility in most common organic solvents make it incredibly difficult to facilitate conversion into hydrogels without concomitant dissolution. It is known that Swift family birds construct strong and sturdy nests with saliva that acts to bind fibers and twigs. Inspired by this charming hierarchical architecture, protonated carboxymethyl cellulose and cellulose were exploited as “saliva” and “twigs,” respectively, and by a combination of freeze–thaw treatments, cellulose hydrogels can be successfully induced without pre-dissolution representing a striking advancement over what is currently known or predicted. The gel materials displayed considerable increases in storage modulus, viscoelastic behaviors, and thermal stability as the cellulose content increases and exhibited unique omniphilic behaviors. Moreover, this bioinspired strategy is much more universal than originally surmised as found by the gelation of bamboo fibers (additionally containing lignin and hemicellulose), illustrative of the versatility. As a bio-inspired strategy, the current work is the first report on a straightforward, simple, green, yet effective gelation protocol to prepare cellulose-based soft materials.

With the rapid development of wearable electronics and the advent of the Internet of Things (IoT) era, it is imperative to research and explore the basic components to meet the application scenarios. In particular, it is becoming increasingly difficult to impart suitable properties to individual materials and realize appropriate physical dimensions in order to satisfy increasing demands of multifunctionality for fundamental studies, device designs, and performance optimization. Therefore, these challenges and opportunities can be addressed by designing (optical) electronic and energy devices with unique functionality and versatility through the combined advantages of multidimensional integration or hybridization of inorganic semiconductors, especially inorganic two-dimensional semiconductor materials, with various types of organic materials with potentially novel functions and unique properties. Herein, a comprehensive review of emerging integration or hybridization of inorganic semiconductor materials with organic materials from their individual components, and assembly fabrication to their state-of-the-art electronic, optoelectronic, magnetic, and energy applications is presented. Future opportunities and challenges associated with these organic/inorganic hybrids are highlighted.