Advanced Composites and Hybrid Materials最新文献

The damping behaviour of polymer nanocomposites which are doped with graphene nano-platelets (GNPs) can be attributed mainly to the interactions between the GNPs and the polymer matrix, as well as to the matrix inherent damping capability. Furthermore, additional mechanisms like interlayer friction between GNP layers that form the GNP flake seem to play a crucial role. However, as the GNP content increases, this leads to agglomeration which reduces the effective surface area in contact with the polymer, lowering the interfacial friction and, consequently, damping. Moreover, excessive GNP content increases the stiffness of the nanocomposite, which can reduce the polymer’s ability to deform and dissipate energy through internal friction. Similar to polymer nanocomposites, the same damping mechanisms take place during carbon fibre reinforced composite (CFRP) damping where additional energy dissipation related to the interaction between the carbon fibres and the GNPs are identified. Nevertheless, for both material cases, there is an optimal concentration of GNP for which damping is maximized due to a balance between enhanced interfacial interaction and energy dissipation. Several specific analyses, qualitative and quantitative, are proposed here as plausible explanations of the damping behaviour observed in these composites.

Passive thermal regulation materials are gaining increasing attention for their sustainability; however, conventional ones are usually limited to a single temperature condition, failing to meet the varying temperature demands across different seasons. To address this challenge, inspired by penguins’ thermoregulatory strategies, this study develops a composite phase change material that enables distinct regulation mechanisms under varying conditions. This material features a Janus surface that can switch between photothermal absorption and radiative cooling to cope with cold daytimes and hot environments; two distinct phase change ranges can maintain temperature balance on comfortable nights and achieve long-term thermal compensation on cold nights. Outdoor tests demonstrated that the material achieves 9.0℃ daytime cooling and extends nighttime comfort duration by 27.3% in hot weather, while in cold weather it averages 11℃ daytime warming and keeps nighttime temperature 0.5℃ above ambient; simulation results further showed that roof application of this material can effectively improve thermal comfort in diverse regions throughout the year. This work integrates photothermal absorption, radiative cooling, and dual-phase change processes, providing a feasible strategy for enhancing all-season thermal comfort in building energy conservation.

Aramid nanofiber (ANF) aerogels possess excellent flexibility and favorable mechanical properties. However, their limited infrared transmittance, relatively high thermal conductivity, and low flame retardancy significantly restrict their application in passive thermal management. In this study, a microphase separation strategy is employed to fabricate ANF@Al₂O₃ composite aerogels, enabling a structural transition from a uniform-pore to a slit-pore morphology. Benefiting from the light regulation by the slit pore structure and the flame-retardant effect of Al₂O₃, the prepared ANF@Al₂O₃ aerogels material have ultra-low thermal conductivity (as low as 30 mW/(m·K)), high infrared transmittance (near-infrared transmittance > 90%), and excellent fire resistance (enhanced combustion endurance), which is able to meet the various needs of passive heating in intelligent buildings. Under outdoor solar irradiation (29.3 °C, 677.6 W/m²), the ANF@Al₂O₃ composite aerogel achieves an internal temperature of 50.46 °C, achieving a relative heating enhancement of 72.22%. This study provides a strategy for designing high-performance composite aramid aerogels and holds great promise for mild thermal insulation applications with potential relevance to aerospace, energy-efficient buildings, and smart thermal management systems.

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Overcoming the challenge of decoupling impedance matching from attenuation for low-frequency (2–10 GHz) electromagnetic wave absorption, this work presents a defect-engineered multiphase medium-entropy sulfide composite. Synthesized via integrated mechanical alloying and surfactant-assisted hydrothermal sulfidation, the composite integrates sulfur vacancy-rich (Fe,Co,Ni)₉S₈, anisotropic FeCoNi alloy, CoFe₂O₄, and porous MoS₂. This architecture creates abundant heterogeneous interfaces and interfacial sulfur vacancies, significantly enhancing defect-induced polarization and dielectric loss via the “Janus effect.” Concurrently, the magnetic components boost magnetic loss while optimizing impedance matching. Benefiting from this magneto-dielectric synergy, the composite achieves exceptional absorption: a minimum reflection loss (RL_min) of -50.4 dB at 3.96 GHz and a remarkable RL_min -77.5 dB at 9 GHz. Radar cross-section simulations confirm application potential. This work provides strategic insights for designing innovative low-/mid-frequency absorbers through synergistic dielectric-magnetic loss in polymetallic sulfide heterostructures.

CuCrZr/Cu/CuCrZr laminated metallic composites (LMCs) were fabricated by hot rolling (HR) followed by cryorolling (CR) and subsequent short-term annealing. The CuCrZr layers accounted for 20.0 vol% of the composite, while the core layer consisted of low-cost pure Cu. The resulting LMCs exhibited enhanced ultimate tensile strength (UTS) and wear resistance relative to the constituent materials. Furthermore, the electrical conductivity of the LMCs was significantly higher than that of the initial CuCrZr (38.3%IACS). After annealing at 673 K for 30 min, the LMCs reached a UTS of 292 MPa, an electrical conductivity of 96.7%IACS, and a wear rate of 2.38 × 10^–4 mm³∙N^–1∙m^–1. These improvements were primarily attributed to optimized precipitation strengthening in the CuCrZr layers and the presence of a high density of annealing twins in the Cu layers. Microstructural characterization revealed uniformly distributed Cr-rich precipitates (≈ 4 nm) in the CuCrZr layer of the CR-A673K sample. Meanwhile, the Cu layer exhibited an annealing-twin area fraction of 43.2% and a 10% increase in the length fraction of Σ3 grain boundaries. This study demonstrates the feasibility of synchronizing CuCrZr aging with Cu recrystallization via CR and short-term annealing, thereby offering a practical design strategy for developing high-performance, low-cost alternatives to pure copper.

The design of wettable membranes with tailored micro- and nanostructures for the efficient separation of oily wastewater remains a challenge. Herein, a cellulose acetate nanofiber/covalent organic framework (ETCNF/COF) composite membrane was fabricated, featuring vertically aligned COF nanorods, achieved via an electrospinning-assisted, amino-mediated in situ confined growth method. Utilizing this vertically arranged COF micro/nano rough structure, the superhydrophobic ETCNF/COF-ODM membrane and superhydrophilic ETCNF/COF-CHA membrane was constructed using thiol-ene click chemical grafting of octadecylthiol (ODM) and cysteamine hydrochloride (CHA) methods, respectively. As a result, the ETCNF/COF-ODM membrane exhibited excellent superhydrophobicity (contact angle > 150°) and self-cleaning properties, enabling the efficient separation of water-in-oil emulsions with a separation efficiency exceeding 99%. In contrast, the ETCNF/COF-CHA membrane exhibited outstanding superhydrophilicity (contact angle approaching 0°) and underwater superoleophobicity (underwater oil contact angle > 150°), achieving high-efficiency separation of oil-in-water emulsions with a separation efficiency above 99%. The superior superwetting performance of both membranes is attributed to the synergistic construction of hierarchical porous superwetting interfaces by the COF and the electrospun substrates. In conclusion, the in situ domain-limited growth of vertically aligned COF nanorods for superwetting membranes by electrostatically spun membranes provides an effective strategy for advancing the development of oil-water separation technology.

Effective heat dissipation is crucial for the optimal performance and safety of electronic devices. Electronic products and energy-efficient home equipment generate more heat during operation and continuous use. Therefore, it is essential to implement efficient heat dissipation methods to prevent problems such as component malfunctions, increased failure rates, and safety hazards. Polymer composites have recently garnered attention due to their unique properties and versatility. These composites achieve improved thermal conductivity by incorporating ceramic nanoparticles, making them suitable for heat dissipation applications. However, challenges arise from the electrical conductivity of ceramic fillers, which can interfere with the performance of precision electronic components. Additionally, the thermal conductivity of ceramic nanoparticles is typically low (less than 10 W/(m·K)), requiring high filler content (above 50 vol.%), which increases the cost and weight of the composite materials. Nanofiber-based heat dissipation sheets, particularly those fabricated through electrospinning, offer a promising alternative. Ceramic nanofibers provide continuous thermal pathways within the polymer matrix, enhancing heat conduction. However, while in-plane thermal conductivity can be significantly improved, the thermal conductivity in the thickness direction remains limited due to the insufficient heat conduction network in this direction. Advanced techniques such as freeze-drying offer promising solutions to this problem, enabling the formation of three-dimensional (3D) interconnected nanofiber networks. These 3D structures demonstrate superior performance over conventional one-dimensional nanofibers. This review provides a comprehensive overview of the synthesis and integration of ceramic nanofibers, including aluminum oxide (Al₂O₃), aluminium nitride (AlN), silicon dioxide (SiO₂), titanium dioxide (TiO₂), and beryllium oxide (BeO), into polymer matrices for heat dissipation applications. It discusses the thermal and electrical performance of these materials alongside emerging strategies to optimize thermal conductivity in both in-plane and thickness directions. Furthermore, this review highlights recent advances in freeze-drying techniques for fabricating 3D nanofiber structures and outlines future directions for overcoming the challenges in synthesizing high-performance ceramic nanofibers.

Alginate, renowned for its exceptional properties, including biocompatibility, biodegradability, surface functionalization, and gel-forming ability, has emerged as a highly effective corrosion-resistant and antifouling material for sustainable applications in aqueous environments. Alginate-based composites exhibit intrinsic self-healing capabilities due to their unique molecular structure, which encapsulates exposed metal surfaces and mitigates further corrosion. Consequently, alginate-based coatings extend the longevity of metal structures while reducing the frequency of maintenance, making them particularly advantageous for long-term use in harsh environments. Previously, some reviews highlighted the general applications of biopolymers; the present report focuses uniquely on alginate and its derivatives as sustainable corrosion inhibitors for aqueous and coating phase applications. The next-generation designs of effective alginate derivatives have been surveyed and proposed by structural modification, grafting, and hybrid nanocomposite integration. This review also highlights the roles of alginate-based coatings in enhancing antifouling performance. Following an overview of fundamental corrosion-resistance mechanisms, we delve into the interfacial and surface properties of alginate-based coatings, including their molecular architecture, amphiphilic characteristics, and key attributes that enhance their effectiveness across various industrial applications, such as ship hulls, undersea infrastructure, and maritime equipment. Additionally, we critically assess the latest research developments, evaluation methodologies, and comparative performance analyses against conventional coatings. Finally, we highlight alginate-based coatings’ advantages, challenges, and future directions for corrosion protection and antifouling applications. The comprehensive review bridges between materials engineering, corrosion science, and green chemistry, and outlines a roadmap for exploring the development of alginate-based coatings for different industries.

Interfacial chemical bonding between carbon fibers (CFs) and the resin matrix plays a critical role in enhancing the mechanical properties of carbon fiber reinforced polymer composites (CFRPs). While grafting functionalized molecules onto CFs can improve their interfacial properties, previous studies have focused on grafting efficiency and content rather than the influence of molecular configurations. Herein, three electrochemical surface treatment methods for the grafting of piperazine (PIP) molecules onto CFs were evaluated. Among them, the cycling electrode-switching electrochemical treatment (C-ESET) was identified as optimal and used to investigate the effect of interfacial molecules on the mechanical properties. The P-s-CF@PIP (Periodic-switching-CF@PIP) was obtained after 210 s of treatment and had a high surface N content of 19.46 at% and a surface energy of 51.23 mN m^− 1. When combined with the epoxy resin (EP) matrix, the average interfacial thickness of the CFRP reached 506.7 nm, resulting in an interlaminar shear strength (ILSS) of 127.9 MPa and a tensile modulus of 244.2 GPa. Furthermore, the distinct configuration-dependent reinforcement mechanisms of linear, heterocyclic and aromatic diamine molecules at the CF/EP interface were elucidated. Thus, this work presents not only a universal surface treatment method for amine-reactive systems but also a molecular-level interfacial design principle for constructing CFRPs with rigid-flexible interphases.

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Segregated conductive polymer composites, in which three-dimensional (3D) conductive networks are formed through the selective localization of conductive fillers, have attracted considerable attention due to their remarkable electrical and thermal conductivities even at low filler contents. Nevertheless, theoretical models that account for their uniquely segregated structures remain limited. Here, we propose advanced segregated electrical and thermal percolation models by considering a hierarchical nano-micro network architecture. The key structural features of this segregated architecture, such as micro-voids and excluded volume, were quantitatively analyzed using 3D non-destructive micro-computed tomography. These structural parameters were incorporated into a conventional percolation model to more accurately represent the segregated network features and to overcome limitations of existing approaches. Furthermore, to mitigate the inevitable degradation in mechanical properties caused by micro-voids formed during the localization of conductive networks at particle interfaces, we developed a facile fabrication method involving the introduction of a terpolymer with a lower melting point than that of the base matrix. This approach significantly reduced micro-void formation, enabling the incorporation of up to 4.93 vol% additional filler into GNP-based segregated composites (G-SC) and up to 12.15 vol% into h-BN-based segregated composites (B-SC). As a result, the G-SC exhibited enhancements of up to 124.07% in electrical conductivity and 68.11% in thermal conductivity, while the B-SC achieved up to a 53.54% improvement in thermal conductivity. These findings demonstrate that nano-micro network optimization through terpolymer incorporation enables the realization of significantly improved conductive performance, validating the effectiveness of the newly proposed segregated percolation models.

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