Advanced Materials Technologies最新文献

Nematic liquid crystals (LCs) offer significant advantages for reconfigurable millimeter-wave (mmWave) devices, but many implementations remain limited to single-band or single-polarized operation and slow switching due to thick LC layers. This work presents a dual-band, dual-polarized reconfigurable metasurface for Ka-band applications operating at 28 and 38 GHz. The design features a symmetric complementary patch/slot metasurface with via-based biasing, integrating a 10 µm LC layer and operating down to a 2 µm gap. This thin profile is achieved through the strong electromagnetic coupling between a patch array and a complementary cross-slot array topology. A key design feature is a 45°-rotated slot in the lower-frequency element that suppresses a parasitic dark-mode resonance, preserving weak inter-band coupling at oblique incidence. Full-wave simulations predict independent phase control at 28 and 38 GHz, and measurements confirm dual-band phase tuning with millisecond-scale switching. This approach provides a practical route to compact, high-performance reconfigurable components for advanced mmWave communication and sensing using LCD-compatible fabrication.

Direction-dependent control of propagating electromagnetic radiation plays a crucial role in emerging photonic technologies, including isolators, circulators, detectors, and sensors. Typically, the directional control is achieved through nonreciprocal mechanisms involving magnetic biasing, spatiotemporal modulation, or nonlinear effects. However, incorporation of these techniques into the terahertz (THz) regime is cumbersome due to the material limitations and integration complexity. In this context, a planar metasurface design composed of geometrically asymmetric split ring resonators (SRRs) is presented, enabling unidirectional reflection. The asymmetry is induced by laterally displacing the capacitive gap in SRRs. The geometrical asymmetry in SRR induces asymmetric radiative loss, resulting in strong reflection from one direction and near-complete suppression from the opposite. This thorough investigations demonstrate a reduction in resonance intensity (and resonance Q-factor) with increasing geometric asymmetry, indicating redistribution of energy stemming from radiative loss engineering. The demonstrated metasurface designs enable controlled unidirectional reflection by accessing dark modes through introducing asymmetry in well accepted SRR-based planar metasurface configuration.

Smart textiles require conductive polymer filaments that balance electrical performance with industrial processability. This study presents a hybrid nanofiller approach combining branched carbon nanotubes (bCNTs) and carbon black (CB) in polyamide 6 (PA6), enabling scalable melt spinning of high-performance conductive filaments. Comparative analysis of PA6/bCNT, PA6/CB, and PA6/bCNT/CB systems established structure–property–processing relationships essential for smart textile applications. Rheological characterization reveals that the hybrid system merges the strong conductive network of bCNTs with the improved spinnability provided by CB, ensuring industrial-scale processability. The optimized PA6/3 wt.% bCNT/3 wt.% CB composite achieved low resistivity (≈50 Ω·cm) while maintaining stable spinning at winding speeds up to 1000 m min⁻¹. A structural evolution model is proposed, showing how CB particles act as bridging agents between aligned bCNTs, stabilizing conductive pathways under high draw ratios. Complementary microscopy, thermal, and mechanical analyses validated this mechanism and confirmed the balance of conductivity, thermal stability, and mechanical performance. By integrating material design, process optimization, and functional validation, this work overcomes key barriers limiting commercial conductive filaments. The developed hybrid technology offers cost-effective, scalable solutions for next-generation smart textiles in wearable electronics, strain sensing, and electromagnetic shielding.

Mechanical metamaterials (MMs) exhibit unique properties through rational design, thereby attracting significant research interest. However, most studies focus on their intrinsic mechanical characteristics, with limited exploration of multifunctional and system-level applications beyond mechanics. This limitation primarily arises from the fabrication of MMs heavily dependent on continuous additive manufacturing, which results in fixed mechanical properties, restricted scale, and degraded structural efficiency, hindering adaptation to multifunctional system demands. To address these aspects, a hierarchical discrete assembly strategy is developed to achieve a synergy of scalability, ultrahigh structural efficiency, and system-level functionality. Upon this strategy, a class of discretely assembled lattice metamaterials (DALMs) with different macroscopic dimensions (>1 m) is fabricated using L-shaped components. Then, compressive responses and failure mechanisms of the DALMs are investigated through experiments and finite element simulations. The DALMs demonstrate an ultralow density of 11 kg m⁻³, with specific stiffness and specific strength reaching 119 and 3 kPa m³ kg⁻¹, outperforming existing modular MMs by 32% and 98%, respectively. Finally, a modular unmanned aerial system (MUAS) is developed by integrating a DALM-based fuselage with functional modules. Compared with similars systems, the MUAS achieves a 85% increase in payload capacity to 1.5 kg, and a 42% increase in thrust-to-weight ratio to 1.76.

Bionic adhesion-based medical adhesives have proven effective in wound treatment, with current research addressing challenges such as weak adhesion and complex fabrication for broader applications. Herein, this work presents a bionic micropillar (MP) for monitoring wound therapy inspired by the physical and chemical properties of gecko toe pads and spider web mucus. Selective incompletely polymerized MP patches are prepared via a simple mold-flipping method, in which spider silk proteins are incorporated into the micropillar matrix. In this design, free silicon–oxygen bonds on the surface spontaneously form physicochemical dual adhesions with the tissue surface, while the spider silk proteins enhance the mechanical stability and biocompatibility. The close adhesion of the patches to the tissue surface, the precise manipulation of fluids by the micropillar channels, and the sensitive response of the patches to small motion changes result in MP patches with excellent data collection and wound status monitoring capabilities. In vivo experiments have demonstrated that MP patches can effectively promote wound healing through efficient wound closure and outstanding biocompatibility. It can thus be concluded that physical and chemical synergistic biomimetic MPs, which integrate spider silk proteins, can be easily prepared, exhibit strong adhesion, and hold significant potential for clinical wound therapy.

Nacre-inspired materials offer excellent fracture toughness through hierarchical architectures, yet their mechanical performance remains limited by pronounced anisotropy. Here, two novel bioinspired microstructures—beetle-like and hexagonal spiral—are presented that enable isotropic toughening in microstructural composites. Using multi-material 3D printing, architected specimens are fabricated and fracture tests are performed along orthogonal loading directions. The beetle-like structure yields critical fracture toughness J₀ = 5.2 and 2 kJ m⁻² along the x- and y- directions, respectively, whereas the hexagonal spiral structure yields J₀ = 5 and 5.5 kJ m⁻², indicating a nearly orientation-independent response. In the x-direction, compared with the nacre-like structure, J₀ increases by 61% and 56% for the beetle-like and hexagonal spiral designs, respectively. While the beetle-like design improves directional toughness, only the hexagonal spiral architecture achieves both enhanced and nearly isotropic fracture resistance. Phase-field fracture simulations reveal how spiral geometry facilitates crack deflection and mixed-mode fracture behavior across multiple orientations. These findings establish a generalizable strategy for overcoming anisotropy in bioinspired composites and provide a robust microstructural platform for high-performance structural materials under complex loading conditions.

Quantum dots (QDs) have emerged as a research focus in optoelectronics owing to their exceptional properties, including ultra-narrow full-width at half maximum, tunable emission wavelengths, high quantum yields, and superior color purity. On the other hand, light-emitting electrochemical cells (LECs), characterized by simple fabrication processes, low-cost manufacturing, and solution processability, represent a promising class of electroluminescent devices. By synergistically combining these merits, QD-based LECs (QLECs) emerge as a highly promising kind of optoelectronic devices for display and lighting applications. In this invited review, it comprehensively examines recent advances in QLECs, providing a systematic overview of innovations in luminescent materials and device optimizations. Fundamental concepts, including QD photophysical properties and LEC operational mechanisms, are first elucidated. Development strategies are then analyzed, emphasizing material engineering approaches and charge dynamics management involving injection, transport, and balance. In addition, the expansion of QLEC devices is also introduced (e.g., light-emitting memory and quantum dot-electrolyte light-emitting diode), clarifying the role of QLECs in pioneering next-generation or new kinds of devices. At the end, current existing challenges and future prospective research directions for advancing this field are discussed. It is expected that this review will provide ideas for developing more possibilities of QLECs.

Triboelectric nanogenerators are expected to be an essential feature of smart electronic devices. They can detect various physical stimuli without requiring an external power source and are known for their flexibility, low-cost, and reliable performance. Due to their potential for monitoring human movements and harvesting energy, they have garnered significant interest. However, developing a triboelectric nanogenerator with high stretchability, flexibility, and output remains challenging. This article introduces a nanocomposite ionic hydrogel triboelectric nanogenerator (NIH-TN) for monitoring human movements and human machine interface (HMI). This flexible nanogenerator uses an ionic hydrogel as an electrode, made up of polyvinyl alcohol (PVA), calcium chloride, and graphene oxide (GO), to improve its electrical and mechanical properties. The introduced structure overcomes the evaporation of liquid and the reduction of performance associated with electrodes based on conductive hydrogels. After investigation of the affecting parameters and using their optimal levels, the NIH-TN performs well and remains stable, with an open-circuit voltage of 180 V, a short circuit current of 15 µA, and a maximum output power of 2.1 W m⁻². It can monitor body movements by placing on the finger, wrist, elbow, and knee joints while it can harvest mechanical energy for powering electronic devices. Additionally, the NIH-TN can be used to create a flexible tactile keyboard.

Antimicrobial resistance (AMR) is a growing global health concern caused by the misuse of antibiotics in medicine, agriculture, and livestock. A major contributor to this crisis is methicillin-resistant Staphylococcus aureus (MRSA), which makes treating common infections difficult. Traditional MRSA detection methods, like culture-based tests and molecular assays, are often slow and expensive, restricting their use in on-site diagnostics. To overcome these limitations, a novel paper-based microfluidic platform has been developed for rapid and accurate MRSA detection. This platform integrates DNA isolation with loop-mediated isothermal amplification (LAMP) and a vertical flow immunoassay (VFI), collectively termed PL-VFI, to target the mecA gene specific to MRSA. Combining simplicity and precision, the device provides results within 1.5 hours without complex handling. It demonstrates high sensitivity and specificity with a detection limit of 10¹ CFU/ml (colony-forming units per milliliter) and 1 fg (femtogram) DNA. Additionally, it successfully detects MRSA in clinical blood samples and offers a long shelf life, making it ideal for on-site DNA diagnostics and resource-limited settings.

In response to the high cost and toxicity of traditional Bi₂Te₃ thermoelectric (TE) materials, this study employs a cation doping strategy to significantly optimize the TE performance of Bi₂Se₃ films, achieving a power factor of 252.6 µW m⁻¹K⁻² at 440 K, which is the highest value for Bi₂Se₃-based flexible TE films synthesized by wet chemical methods. This improvement is attributed to the increase in electrical conductivity induced by Ag doping and the synergistic effects of energy filtering and doping effects. In addition, the Ag-doped Bi₂Se₃ film exhibits excellent flexibility and stability with only a 7% decrease in electrical conductivity after undergoing 2000 bends (with a radius of 4 mm). A flexible TE generator constructed based on the film outputs a power density of 123.4 µW cm⁻² at a temperature gradient of 33.5 K, validating its effectiveness in TE conversion. In addition to traditional applications such as wearable and portable energy harvesting and sensing, the film also holds great potential in emerging fields such as photoelectric conversion and electrochemical energy storage systems. The high TE performance, flexibility, cost-effectiveness, and multifunctional application of the film make it a promising candidate for next-generation energy conversion and storage technologies.