Advanced Composites and Hybrid Materials最新文献

Thermoelectric hydrogels have drawn increasing research interest owing to their high ionic thermopower (α) values and superior mechanical stretchability. However, they are critically constrained by rapid dehydration and the poor interactions between polymeric frameworks and electrolytes, which fail to differentiate the diffusion rates of cations and anions under a certain temperature gradient (ΔT). This study reports a dual-channel ionic/electronic composite hydrogel implemented by directional freezing a cross-linked network of PEDOT:PSS-coated poly(vinyl alcohol) (PVA) and then immersion into an ionic electrolyte of CuCl₂. Introducing 5 vol% conductive polymer PEDOT:PSS aqueous solution into the PVA hydrogel strengthened chemical coordination between the polymer matrix and Cu²⁺ ions to facilitate mobile Cl^‒ ions, resulting in an ultrahigh α of ‒22.8 mV K⁻¹, further elevated to − 33.8 mV K^–1 via freezing–thawing cycles. Driven by ΔT, holes accumulate at the cold end of the composite hydrogel, in part neutralizing Cl^‒ migration and mitigating open-circuit voltages to an equilibrium value, whereas holes drifting toward electrodes allow charge extraction to the external circuit. Notably, the composite hydrogel₂ retained 90% of the peak voltage in a steady state at an optimum 0.5 M CuCl₂. Furthermore, introducing CuCl₂ doubles the water retention capacity of the hydrogel and simultaneously endows it with excellent re-usability and long-term stability. A hybrid thermoelectric generator delivers a stable output of ‒4.0 mV K⁻¹ with a 100 kΩ external load. Such a device permits generating electricity continuously under not only temperature fluctuations but also a stable ΔT.

Infected skin wounds represent a significant healthcare challenge, affecting millions of patients worldwide and imposing substantial economic burden on healthcare systems. Traditional wound dressings and systemic antibiotics face critical limitations including lack of tissue adhesion in wet environments, increasing antibiotic resistance, and inability to promote tissue regeneration, resulting in suboptimal healing outcomes. In this research, we formulated an injectable composite hydrogel comprising dopamine-modified sodium alginate, chondroitin sulfate, and silk fibroin as the primary matrix, with magnesium oxide (MgO) nanoparticles and human umbilical mesenchymal stem cells (hUMSCs)-derived exosomes (Exo) as functional components. The resultant ACS/MgO/Exo hydrogel exhibits effective tissue adhesion, superior hemostatic capability, mild-photothermal therapy (M-PTT)-mediated antibacterial activity, and enhanced angiogenesis. In vitro studies demonstrated that the hydrogel effectively reduced bleeding time, eliminated bacteria through M-PTT, and significantly enhanced endothelial tip cell activation, proliferation, motility, and vascularization through activation of the PI3K-AKT-NF-κB-VEGF signaling cascade. In vivo experiments with infected full-thickness defect model confirmed the composite hydrogel’s ability to accelerate wound closure, eliminate bacterial infection, enhance collagen deposition, and promote vascularization while simultaneously modulating the inflammatory response. This multifunctional hydrogel represents a promising therapeutic platform for complex infected wound management, addressing the critical clinical need for integrated solutions that simultaneously achieve adhesion, hemostasis, infection control, and tissue regeneration.

Adaptive structures capable of controlled shape change are increasingly demanded in fields such as aerospace, architecture, and automotive engineering. In these applications, shell-like deformations are essential for achieving smooth surface transitions that satisfy aesthetic requirements or improve aerodynamic performance. While pressure-actuated cellular structures (PACS) and bio-inspired designs have demonstrated promising morphing capabilities, they often involve high geometric complexity, rely on antagonistic actuation systems requiring energy input in both directions of motion, or face limitations in manufacturability. Inspired by biological systems such as insect wings, this study presents a novel approach to implement shell-like deformations in planar, mold-free manufacturable, thermoplastic fiber-reinforced hybrid composites using embedded pneumatic actuators which are integrated into pre-formed cavities within the laminate setup. Previous implementations have been limited to uniaxial bending deformations. In contrast, the integration of multiple actuators enables shell-like deformations through coupled bending axes. Unlike antagonistic systems, the elastic stiffness of the fiber-reinforced composite serves as a passive restoring force, allowing for reversible deformation without additional counteractuation or mechanical complexity. In this study, a simplified geometric model combined with a regression-based approach is developed to predict deformation as a function of actuation pressure p, actuator width w, and the spacing d between coupled actuators and thereby eliminate the need for computationally intensive FEM simulations. The model is validated within the tested range of p (0.0 to 1.8 bar), w (20 to 50 mm) and d (10 to 40 mm): bending angles of up to 92 (^{circ }) and corresponding shell radii as small as 50 mm were reproducibly achieved, with a coefficient of determination of ({R}^{{2}}) = 0.96 for ({w = }) 20 mm, for example. The proposed design strategy bridges the gap between biologically inspired compliant mechanisms and scalable technical implementation of adaptive shell-like components, offering a low-complexity solution based on a planar, mold-free manufacturing approach.

The integration of high load-bearing capacity, minimal deformation, and high damping remains a major challenge for energy-absorbing materials. Here, we developed a custom coaxial polymer–metal filament fabrication system. By employing NiTi continuous filaments with high damping and tunable stiffness as the core and encapsulating them with a highly damping viscoelastic polymer shell, we fabricated coaxial NiTi/viscoelastic polymer filaments that simultaneously deliver superior damping capacity and robust load-bearing performance. The effects of filament diameter and polymer diluent concentration on the thermomechanical behavior and damping properties were systematically investigated. Hysteresis tests under varying loading rates were conducted to evaluate the rate-dependent energy dissipation behavior. Ball drop impact tests and simulations on the composite filament mesh demonstrated superior energy absorption capacity compared to pure NiTi mesh and other damping materials. Vibration isolation tests and simulations confirmed its excellent and tunable low-frequency isolation performance. This approach offers a new pathway to achieving an optimal balance between damping capacity and stiffness in NiTi-based energy absorbing materials, with potential applicability to other material systems and scalable manufacturing.

The rational design of heterogeneous interfaces in multilayered structures to enhance interfacial polarization, combined with the strategy of electromagnetic wave (EMW) propagation pathways within composites, represents an effective approach to overcoming the limitations of electromagnetic wave absorption (EMWA) performance. In this work, a multi-interface EMW absorber with a unique EMW transmission pathway was designed, based on the distinctive hollow octahedral structure of MIL-101 and its integration with various microstructural configurations. Multicomponent composites were fabricated via hydrothermal synthesis and electrostatic self-assembly. By leveraging the unique properties of each component, multiple heterogeneous interfaces were constructed, effectively promoting interfacial charge transfer and significantly enhancing interfacial polarization, which in turn facilitates the conversion of electromagnetic energy into heat. The results demonstrate that the RL_min of the prepared CoFe₂O₄@MIL-101@MoS₂/GO (CFMMG, and GO stands for Graphene Oxide) is -55.13 dB, with a thickness of 2.69 mm at 11.4 GHz, while the EAB at 2.37 mm reached 6.3 GHz (9.8–16.1 GHz). Furthermore, first-principles density functional theory (DFT) simulations were conducted to theoretically elucidate the influence of interfacial polarization on the enhanced EMWA capability. This study provides distinctive insights into multi-interface composite cooperation in EMWA engineering.

Engineering native-mimetic tissue constructs is challenging due to their intricate biological and structural gradients. To address this, Hybprinter-SAM was developed by integrating three bioprinting technologies: syringe extrusion (SE), acoustic droplet ejection (ADE) and molten material extrusion (MME). This system not only enables the creation of mechanical gradients by integrating soft and rigid materials spanning 7 order magnitude of stiffness but also facilitates precise patterning and controlled localization of biochemical signals within printed scaffolds. This capability is beneficial in replicating the complexity of native tissues to enhance functionality. Both the printing process and biomaterials were optimized to balance printability, mechanical integrity, and biocompatibility. As a proof of concept, Hybprinter-SAM was used in a bone-tendon regeneration study to engineer a multi-material construct with patterned fibroblast growth factor 2 (FGF-2), resulting in markers indicative of fibrocartilage development. These findings highlight the potential of Hybprinter-SAM as a versatile platform for diverse tissue engineering applications that require complex, functionally graded tissue constructs.

Interface defects can significantly diminish the protective performance of a system. Specifically, coating aging is accelerated markedly by UV radiation, high temperature, high humidity, and microbial attack. To address these issues, this study develops a functional integrated intelligent coating with anti-corrosion and anti-fouling capabilities (SCC/ZPhP) via interfacial reinforcement and multi-component composite engineering. In this system, sericite (SC) acts as both a barrier and a loading platform, aiming to enhance the coating’s barrier performance while mitigating particle aggregation. Furthermore, constructing a Ce/Zn heterostructure (C/Z) reduces the composite’s band gap (E_g), which effectively promotes charge separation and improves photocatalytic and photocathodic protection properties. 1,10-Phenanthroline encapsulated in polyacrylic acid (PhP) exhibits pH-responsive behavior, enabling on-demand release of the active component. The resulting red coloration facilitates visual identification of corrosion areas and supports self-healing protective effects. Compared to epoxy coatings (EP), the SCC/ZPhP coating demonstrates better weathering and anti-aging performance, maintaining impedance modulus of 10¹⁰ Ω·cm² and 10¹¹ Ω·cm² after the exposure period. Moreover, the incorporation of active factors endows the coating with excellent anti-fouling capabilities, achieving an antimicrobial rate of up to 98%. This effectively inhibits the adhesion and accumulation of marine organisms, thereby significantly reducing the risk of structural damage. Therefore, this study proposes a novel design strategy for developing multifunctional intelligent protective coatings with anti-corrosion and anti-fouling functionalities. Such coatings offer promising potential to extend the service life and enhance the structural stability of offshore engineering systems.

Graphical abstract

There is a growing interest in harnessing sustainable plant fibre-reinforced composites (PFRCs) in key industrial applications due to their sustainable and eco-friendly attributes in comparison to their conventional counterparts, such as glass and carbon fibres. However, these plant fibres are susceptible to moisture absorption, resulting in the degradation of mechanical properties, dimensional instability, and reduced long-term performance. On the other hand, understanding and predicting the moisture absorption behaviour are essential for enhancing the reliability and performance of these materials for the full exploitation of their potential. The majority of existing review papers have primarily concentrated on experimental investigations of moisture absorption in PFRCS, with minimal attention given to Finite Element Analysis (FEA)-based approaches. Despite these advances, there is still a lack of literature dedicated to the modelling of moisture diffusion characteristics of natural plant fibre-reinforced composites, particularly in hybrid configurations, since only very limited studies have addressed the multi-scale phenomena and the integration of experimental validation. Therefore, this review paper critically analyses the recent progress in the FEA at micro, meso and macro modelling of the moisture absorption process of plant fibre composites and their hybrids and also focuses on experimental validation in relation to ageing mechanisms and long-term durability of plant fibre reinforced composites. Further this review paper provides a comprehensive analysis of FEA-based moisture absorption modelling in PFRCs and their hybrids, focusing on it as a critical resource for researchers and engineers aiming to enhance the durability and performance of sustainable composites in real-world applications.

We report multifunctional ultrahigh molecular weight (UHMWPE)/graphene nanoplatelet (GNP) nanocomposites with controlled GNP segregation for barrier applications. The nanocomposites were fabricated by a simple yet scalable solution mixing technique, followed by hot-press moulding, and a novel segmentation approach was used to quantify the fraction of GNP coverage on polymer granules in different concentrations ranging from 0.5 to 10 wt.%. High-resolution X-ray computed tomography (micro-CT) analysis confirmed the formation of a segregated structure. Owing to this morphology, the CO_2(g) permeability of the nanocomposites decreased by 20% with just 0.5 wt.% GNPs, with further improvement seen at higher concentrations. The well-established Nielsen model showed a good fit between the analytical and experimental permeability values. The diffusion coefficient of the nanocomposites for the solvent uptake also dropped by up to 21% compared to the neat specimens. Regarding mechanical properties, the storage and tensile moduli increased linearly with increasing GNP concentration, showing 72% and 61% increases, respectively, at 10 wt.% GNP compared to the neat UHMWPE specimens. Most importantly, the stiffness increase of the nanocomposites was accompanied by minimal loss of ductility and no additional wear loss at GNP concentrations up to 3 wt.%. In addition, the formation of a segregated network in the nanocomposites ensured a low electrical percolation threshold of 0.82 vol.%. These findings highlight the potential of these nanocomposites for multiple high-performance applications as promising candidates for per- and polyfluoroalkyl substances (PFAS)-free sealants.

To overcome the threats of microwave technologies, refine the electromagnetic waves (EMWs) pollution, and develop the stealth and cloaking applications, EMW absorbing/shielding materials have burgeoned. Among various materials applied as microwave absorbers, the MXenes, as a growing two-dimensional (2D) transition metal carbides/nitride family, have emerged as revolutionary materials for electromagnetic interference (EMI) management due to their exceptional conductivity, regulable surface chemistry, tunable morphology, and hierarchical structure, desirable for microwave absorption/shielding (MA/MS) applications. Along with all the advantages mentioned, MXene also suffers from disadvantages like oxidation susceptibility, significant electrical conductivity and impedance mismatch, limited absorption contribution, structural collapse under mechanical or hygrothermal stress leading to degradation of shielding effectiveness, and challenges in scalable fabrication of large-area, lightweight films, preventing it from being used alone as a MA/MS material. To enhance absorbing properties and to resolve the drawbacks of the MXene, diverse structures, including ceramics, polymers, metal NPs (MNPs), alloy structures, and metal oxide NPs (MONPs), are introduced. This review focuses on the MNPs, alloys, and MONPs, bringing permeability and promoting impedance matching and other shortcomings of the eventual product. The mentioned composites have many advantages for MA/MS applications, including broadening the specific surface area, tuning conductivity, layering and etching the structure, and boosting polarization, among others. The review illustrates the future horizons for tailoring MXenes as MA/MS game-changers, exploring the latest developments in MXene-based metal oxide/metal composites. The focus of this review is on the emerging frontier of design strategies, experimental breakthroughs, and EMW absorbing/shielding properties of MXene-based metal oxide/metal composites. The review highlights the broader coverage of composite systems, provides deeper mechanistic insights, and supplies a more integrated perspective on design strategies relating to the MONPs and MNPs/MXene composites—compared to prior reviews. By gathering the finest of both worlds from the blessed combination of MXene and metal structures, the fascinating MA/MS properties with unique capabilities are achievable, opening new vistas for future practical applications.