Search Results (203)

The widespread use of wireless technologies raises concerns about health effects and electromagnetic interference (EMI). This study aims to investigate the EMI-shielding properties of functional textiles using modified multi-walled carbon nanotubes (MWCNT) dispersed in different polymeric matrices as coating inks. Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) combined with MWCNT showed promise. For instance, a textile coated with a PEDOT:PSS-based ink containing 5 wt.% of N-doped MWCNT with a thickness of 140 µm achieved a shielding effectiveness (SE) of 31.0 dB (221 dB µm⁻¹) in the 5.85–18 GHz range. This fabric is classified as ‘excellent’ for general use and may be suitable for EMI-protective clothing. Some tests using silicone as a polymer matrix demonstrated improved SE through resonance phenomena. Full article

Transition metal (TM)-doped zinc oxide (ZnO) and zirconium dioxide (ZrO₂) nanocrystals exhibit complex correlations between crystal structure, defect chemistry, vibrational properties, and magnetic behavior that are strongly governed by synthesis route and dopant incorporation mechanisms. This review critically summarizes recent progress on Fe-, Mn-, and Co-doped ZnO and ZrO₂ nanocrystals synthesized by wet chemical, hydrothermal, and microwave-assisted hydrothermal methods, with emphasis on synthesis-driven phase evolution and apparent solubility limits. ZnO and ZrO₂ are treated as complementary host lattices: ZnO is a semiconducting, piezoelectric oxide with narrow solubility limits for most 3d dopants, while ZrO₂ is a dielectric, polymorphic oxide in which transition metal doping may stabilize tetragonal or cubic phases. Structural and microstructural studies using X-ray diffraction, electron microscopy, Raman spectroscopy, and Mössbauer spectroscopy demonstrate that at low dopant concentrations, TM ions may be partially incorporated into the host lattice, giving rise to diluted or defect-mediated magnetic behavior. When solubility limits are exceeded, nanoscopic secondary oxide phases emerge, leading to superparamagnetic, ferrimagnetic, or spin-glass-like responses. Magnetic measurements, including DC magnetization and AC susceptibility, reveal a continuous evolution from paramagnetism in lightly doped samples to dynamic magnetic states characteristic of nanoscale magnetic entities. Vibrational spectroscopy highlights phonon confinement, surface optical phonons, and disorder-activated modes that sensitively reflect nanocrystal size, lattice strain, and defect populations, and often correlate with magnetic dynamics. Rather than classifying these materials as diluted magnetic semiconductors, this review adopts a synthesis-driven and correlation-based framework that links dopant incorporation, local structural disorder, vibrational fingerprints, and magnetic response. By emphasizing multi-technique characterization strategies required to distinguish intrinsic from extrinsic magnetic contributions, this review provides practical guidelines for interpreting magnetism in TM-doped oxide nanocrystals and outlines implications for applications in photocatalysis, sensing, biomedicine, and electromagnetic interference (EMI) shielding. Full article

With the rapid advancement of modern electronic devices and wireless communication systems, electromagnetic pollution has become a prominent issue, prompting the development of high-performance electromagnetic interference (EMI) shielding materials. Although traditional metal shielding materials exhibit excellent conductivity, there are many limitations such as high weight, poor flexibility, susceptibility to corrosion, and high cost. To overcome these challenges, in this study, we design and fabricate core-spun yarns using polyester filaments as the core and an aluminum-foil-wrapped layer as the conductive outer component, and further weave them into three conductive fabrics with different structural parameters. Through systematic investigation of their surface morphology, air permeability, electrical properties, and EMI shielding performance, DT5W27 demonstrates optimal overall performance: electrical conductivity of 2722.64 S·m⁻¹, shielding effectiveness of 37.29 dB, and electromagnetic wave attenuation rate of 99.99%. Specifically, even after 100 bending, twisting cycles, and exposure to solutions with pH values ranging from 3 to 9, the fabric maintains high shielding performance. The fabrication process is facile and low cost, and these composites have good flexibility, outstanding EMI shielding performance, exceptional mechanical durability, and chemical stability. These advantages make them have broad application potential in protective clothing and lightweight shielding materials. Full article

The continuous advancement of modern weaponry has intensified the pursuit of next-generation ballistic protection systems that integrate lightweight architectures, superior flexibility, and high energy absorption efficiency. This review provides a technological overview of current trends in the design, processing, and performance optimization of metallic, ceramic, polymeric, and composite materials for ballistic applications. Particular emphasis is placed on the role of advanced surface coatings and nanostructured interfaces as enabling technologies for improved impact resistance and multifunctionality. Conventional materials such as high-strength steels, alumina, silicon carbide, boron carbide, Kevlar^®, and ultra-high-molecular-weight polyethylene (UHMWPE) continue to dominate the field due to their outstanding mechanical properties; however, their intrinsic limitations have prompted a transition toward nanotechnology-assisted solutions. Functional coatings incorporating nanosilica, graphene and graphene oxide, carbon nanotubes (CNTs), and zinc oxide nanowires (ZnO NWs) have demonstrated significant enhancement in interfacial adhesion, inter-yarn friction, and energy dissipation. Moreover, multifunctional coatings such as CNT- and laser-induced graphene (LIG)-based layers integrate sensing capability, electromagnetic interference (EMI) shielding, and thermal stability, supporting the development of smart and adaptive protection platforms. By combining experimental evidence with computational modeling and materials informatics, this review highlights the technological impact of coating-assisted strategies in the evolution of lightweight, high-performance, and multifunctional ballistic armor systems for defense and civil protection. Full article

In this study, Fe₃O₄-chopped carbon fiber (CF) fillers with varying CF:Fe₃O₄ weight ratios (1:0.5, 1:0.75, and 1:1) were fabricated using the wet chemical reduction method. Different weight percentages (1, 3, 7 wt.%) of the CF/Fe₃O₄ fillers were used to fabricate lightweight, flexible, and porous thermoplastic polyurethane (p-TPU) composites for electromagnetic interference (EMI) shielding applications. Due to its poor electrical and magnetic properties, the TPU matrix alone exhibited negligible shielding effectiveness. The electromagnetic interference (EMI) performance of TPU composites is greatly affected by the amount of filler materials, the CF/Fe₃O₄ ratio, and the porous structure, which in turn influence the interfacial interactions between filler and p-TPU matrix. Effective electromagnetic attenuation is achieved by conductive CF network, interfacial polarization at CF/Fe₃O₄/TPU interfaces, and multiple internal reflections promoted by microstructural heterogeneity and porosity. A maximum EMI shielding effectiveness (SE_T) of 22.28 dB was achieved for a CF/Fe₃O₄/p-TPU composite with a filler load of 7 wt.%, a CF:Fe₃O₄ ratio of 1:1, and a porosity of 15%. Full article

Magnetic soft manganese–zinc ferrite in a concentration scale ranging from 100 to 500 phr was incorporated into acrylonitrile-butadiene rubber. The work was focused on the investigation of manganese–zinc ferrite content on electromagnetic interference shielding effectiveness and mechanical properties of composites. The rubber-based products used in industrial practice should not only provide good utility and functional properties but should also exhibit good stability towards degradation factors, like oxygen and ozone. Therefore, the samples were exposed to the thermo-oxidative and ozone ageing conditions, and the influence of both factors on the composites’ properties was evaluated. The results demonstrated that the incorporation of ferrite into the rubber matrix resulted in the fabrication of composites with absorption-shielding performance. It was demonstrated that the higher the ferrite content, the lower the absorption-shielding ability. Electrical and thermal conductivity showed an increasing trend with increasing content of ferrite. On the other hand, the study of mechanical properties implied that ferrite acts as a non-reinforcing filler, leading to a decrease in tensile characteristics. Thermo-oxidative ageing tests revealed that ferrite, mainly in high amounts, could accelerate the degradation processes in composites. Though the absorption-shielding performance of composites after ageing corresponded to that of their equivalents before ageing, it can also be concluded that the higher the amount of ferrite in the rubber matrix, the lower the composites’ stability against ozone ageing. Full article

The present study explores the comparative influence of reduced graphene oxide (rGO), silver nanowires (AgNWs), and their hybrid rGO–AgNWs on the electromagnetic interference (EMI) shielding performance of polyaniline (PANI)-based flexible films prepared using a polycaprolactone (PCL) matrix. The nanocomposites were synthesized through in situ oxidative polymerization of aniline in the presence of individual or hybrid fillers, followed by their dispersion in the PCL matrix and casting of the corresponding films. Morphological and structural characterization (SEM, Raman, and FTIR spectroscopy) confirmed a uniform PANI coating on both rGO sheets and AgNWs, forming hierarchical 3D conductive networks. Thermal (TGA) and thermomechanical (TMA) analyses revealed enhanced thermal stability and stiffness across all composite systems, driven by strong interfacial interactions and restricted polymer chain mobility. Tmax increased from 437.9 °C for neat PCL to 487.9 °C for PANI/PCL, 480.6 °C for PANI/rGO/PCL, 499.4 °C for PANI/AgNWs/PCL and 495.0 °C for the hybrid PANI/rGO–AgNWs/PCL film. The gradual decrease in contact angle following the order PANI/AgNWs/PCL < PANI/rGO–AgNWs/PCL < PANI/rGO/PCL < PANI/PCL < PCL clearly indicates a systematic increase in surface polarity and surface energy with the incorporation of conductive nanofillers. Electrical conductivity reached 60.8 S cm⁻¹ for PANI/rGO/PCL, gradually decreasing to 27.4 S cm⁻¹ for PANI/AgNWs/PCL and 22.1 S cm⁻¹ for the quaternary hybrid film. The EMI shielding effectiveness (SET) measurements in the X-band (8–12 GHz) demonstrated that the PANI/rGO/PCL film exhibited the highest attenuation (~7.2 dB). In contrast, the incorporation of AgNWs partially disrupted the conductive network, reducing SE to ~5–6 dB. The findings highlight the distinct and synergistic roles of 1D and 2D fillers in modulating the electrical, thermal, and mechanical properties of biodegradable polymer films, offering a sustainable route toward lightweight, flexible EMI shielding materials. Full article

In this study, 8-ply 3K carbon fiber fabrics were spray-coated with Ag/RGO nanoparticles at varying weight ratios (0, 2.5, and 5 w/w). Composite specimens were fabricated, consisting of an unmodified control sample (neat) and three different variants containing 0.075 w/w% RGO, 0.26 w/w% AgRGO, and 0.45 w/w% AgRGO, respectively. The effects of RGO and AgRGO contents on the electrical conductivity, flexural properties, dynamic mechanical properties, and electromagnetic interference shielding (EMI) performance of these composites were investigated. Additionally, the distribution of RGO and AgRGO on the surfaces and interfaces of carbon fibers was examined using field emission scanning electron microscopy to determine the microstructure–property relationship. The increase in the Ag ratio in the AgRGO filler material in the composite from 2.5 to 5 resulted in an increase in both the through-the-thickness and surface conductivity values by 3.5 times, reaching maximum conductivity values (273 × 10⁻³ S/m and 256 × 10⁻³ S/m, respectively). Composites containing filler material with an Ag/RGO weight ratio of 2.5 achieved a total electromagnetic shielding efficiency of 18 dB at the X-band frequency region, without loss in flexural strength, while the maximum total electromagnetic shielding efficiency value of 22.68 dB was obtained when the Ag/RGO weight ratio was 5. With a maximum SE_T value these composites might be suitable for use in areas that do not require primary load-bearing applications, such as satellite, antenna, and avionics system housings. Full article

Transparent conductive electrodes that combine flexibility with effective electromagnetic interference (EMI) shielding are important for next-gen flexible electronics and 5G/6G communication devices. Achieving high optical transparency, low sheet resistance, and broadband shielding performance remains a sophisticated task. This work demonstrates a solution: the synthesis and comprehensive characterization of flexible In₂O₃/Ag/In₂O₃ (IAI) structures on polyethylene terephthalate substrates. The optimized structure with a 13.2 ± 1.1 nm silver interlayer achieves an incredible combination of properties: high optical transmittance (82.59% at 500 nm), low sheet resistance (6.4 ± 0.8 Ω/sq), and insignificant optical haze (1.04%). Broadband EMI shielding measurements from 10 MHz to 1 THz reveal a uniform shielding effectiveness of 25–30 dB across band from radiowave to terahertz. The IAI structures also show outstanding mechanical resilience, maintaining their electrical and shielding performance under repeated bending. This unique set of attributes positions IAI thin films as a prospective material for transparent EMI shielding in advanced telecommunications and flexible optoelectronics. Full article

Shape memory polymers (SMPs) are a class of smart materials that exhibit unique shape-fixing and recovery abilities, attracting wide attention for applications in electronics, aerospace, and biomedical engineering. Chitosan (CS) as a renewable biopolymer, possessing good biocompatibility, biodegradability, and antimicrobial properties; its use as a matrix enhances the environmental compatibility and bio-adaptability of SMPs. MXene, as a novel two-dimensional material, is characterized by high electrical conductivity, abundant surface functional groups and good hydrophilicity, showing potential in energy storage, electromagnetic shielding and sensing. In this work, CS and poly (vinyl alcohol) (PVA) were used as the polymer matrix, and carbon nanotubes (CNTs) together with MXene were introduced as co-fillers to construct multifunctional composites. The effect of the CNTs/MXene hybrid fillers on mechanical properties, electromagnetic shielding and multi-stimuli-responsive shape memory behavior was systematically investigated. After ratio optimization, the composites showed excellent comprehensive performance: tensile strength reached up to 20.0 MPa, Young’s modulus up to 292.2 MPa, and maximum elongation at break of 23.2%; electromagnetic interference shielding effectiveness (SE_T) in the X-band (8.2–12.4 GHz) reached a maximum of 10.6 dB; shape fixation rates exceeded 90%; under thermal stimulation, a shape recovery ratio of 98.3% was achieved within 41.7 s; light-driven recovery rate reached 86.5% with a minimal recovery time of 82.3 s; under electrical stimulation the highest recovery rate was 94.1% with a shortest recovery time of 30 s. This study successfully prepared functional multi-stimuli-responsive shape memory composite films and provided a new strategy for the design of green smart materials. Full article

The remarkable growth of high-frequency electronic systems has raised concerns about electromagnetic interference (EMI), emphasizing the need for lightweight and efficient shielding materials. In this study, ternary composites based on polypyrrole (PPy), graphene oxide (GO), and silver nanowires (AgNWs) were synthesized through chemical oxidative polymerization of pyrrole monomer and embedded into polycaprolactone (PCL) matrices to create flexible films. Structural and morphological analyses confirmed the successful incorporation of all components, with scanning electron microscopy showing granular PPy, sheet-like GO, and fibrous AgNWs, while spectroscopic studies indicated strong interfacial interactions without damaging the PPy backbone. Thermomechanical analysis revealed that GO increased stiffness and defined the glass transition, whereas AgNWs improved toughness and energy dissipation; their combined use resulted in balanced properties. EMI shielding effectiveness (SE) was tested in the X-band (8–12 GHz). Pure PPy exhibited poor shielding ability, while the addition of GO and AgNWs significantly enhanced performance. The highest EMI SE values were observed in PPy/GO–AgNWs composites, with an average SE of 16.05 dB at 20 wt% of the composite in the PCL matrix, equivalent to about 84.4% attenuation of incident waves. These results demonstrate that the synergistic integration of GO and AgNWs into PPy matrices enables the creation of lightweight, flexible films with advanced EMI shielding properties, showing great potential for next-generation electronic and aerospace applications. Full article

In this research, thermoplastic waste (polyethylene and propylene) from waste electrical and electronic equipment (WEEE) was used to manufacture polymer composite materials that included talc, fly ash, and elastomers, with tailored electromagnetic interference shielding properties, for the potential use for electric car components. A distribution of inorganic components within the polymer structures without particle clustering were observed, illustrating an effective melt compounding process. The gradual replacement of talc with fly ash lowered both the fluidity index and the softening temperature values. The increase in fly ash content resulted in higher values of both permittivity and dielectric loss factor. The novelty was related to a significant increase in both dielectric characteristics at increased quantities of fly ash at higher temperatures, an aspect more relevant at higher frequencies where they approached a steady value. The permittivity values surpassed five, and the dielectric loss factor values exceeded 0.04, fulfilling the requirements for their application in electrical equipment. The recipes containing 10% fly ash may guarantee an electromagnetic shielding effectiveness of at least 99% within the frequency domain of 0.1–4 GHz. Composites with greater amounts of fly ash can conduct heat more efficiently, leading to improved diffusivity and thermal conductivity values, with significant thermal conductivity values surpassing 0.2 W/(m*K). Finally, it was concluded that the composites with 10% talc, 10% fly ash, and elastomer using recycled high-density polyethylene might be the best choice for electric vehicle parts, in line with all required standards for these uses. Full article

Electromagnetic shielding materials are pivotal for suppressing electromagnetic radiation and mitigating potential health risks that electronic devices may pose to humans. Beyond health protection, they also hold significant strategic value in safeguarding national information security and maintaining stability. In the research of electromagnetic shielding materials, continuous technological advancements and growing application demands have driven the emergence of various novel materials. Among these, liquid metal (LM) exhibits outstanding properties—including exceptional electrical conductivity, excellent fluidity, and superior deformability—which endow it with substantial potential for application in electromagnetic shielding. Looking ahead, with the continuous advancement in related technologies, liquid metal-based electromagnetic shielding materials are expected to provide effective solutions to key challenges such as electromagnetic pollution and interference. This contribution synthesizes the latest literature. First, it clarifies the nomenclature and classification of liquid metals, as well as the fundamental framework for electromagnetic shielding. Then, it systematically distills recent research advances based on four key design motifs. These motifs include monolithic liquid metal (LM) scaffolds, LM/conductive-filler blends, LM/magnetic particle composites, and architectured multifunctional architectures. Finally, this review identifies current bottlenecks in the field and outlines directions for future development, which aim to achieve ultra-lightweight, broadband, and intelligent LM-based electromagnetic shields. Full article

An environmentally friendly biodegradable and flexible polymer with exceptional mechanical, thermal and electromagnetic interference shielding is urgently needed to reduce environmental pollutants and electromagnetic waves to preserve human health. The paper presents our study where we developed biodegradable electrospun nanocomposite by employing polybutylene succinate (PBS) with multiwalled carbon nanotubes (MWCNTs). The crystallization temperature Tc and melting temperature Tm of electrospun PBS/MWCNT composites with 3 wt% of MWCNTs was increased noticeably by 4 °C and 5 °C. The tensile strength increased by about 2.61 ± 0.15 MPA and the elastic modulus increased by about 0.72 ± 0.02 GPa with the addition of 3% MWCNT in polybutylene succinate. The increase in MWCNT content from 0.5 to 3 wt% led to an enhanced storage modulus and electrical properties 5 to 8 times higher in comparison to PBS. Moreover, the MWCNT was tested in different concentrations in PBS for electromagnetic interference shielding (EMI) and the most applicable results were obtained when the MWCNT was 3% which is capable of providing 25.5 db EMI shielding efficiency. The percolation threshold capability of PBS/MWCNT electrospun nanocomposites was 0.94 wt% and has significant entanglement of the MWCNTs and MWCNT network in the PBS matrix for conductive pathways. The study offers a viable process for creating an electrospun PBS/MWCNT composite that is lightweight, biodegradable and has exceptional electromagnetic shielding capabilities. Full article

Polyimide, a class of high-performance polymers, is renowned for its exceptional thermal stability, mechanical strength, and chemical resistance. However, in the context of high-integration and high-frequency electronic packaging, polyimides face critical challenges including relatively high dielectric constants, inadequate thermal conductivity, and mechanical brittleness. Recent advances have focused on molecular design and composite engineering strategies to address these limitations. This review first summarizes the intrinsic properties of polyimides, followed by a systematic discussion of chemical synthesis, surface modification approaches, molecular design principles, and composite fabrication methods. We comprehensively examine both conventional polymerization synthetic routes and emerging techniques such as microwave-assisted thermal imidization and chemical vapor deposition. Special emphasis is placed on porous structure engineering via solid-template and liquid-template methods. Three key modification strategies are highlighted: (1) surface modifications for enhanced hydrophobicity, chemical stability, and tribological properties; (2) molecular design for optimized dielectric performance and thermal stability; and (3) composite engineering for developing high-thermal-conductivity materials with improved mechanical strength and electromagnetic interference (EMI) shielding capabilities. The dielectric constant of polyimide is reduced while chemical stability and wear resistance can be enhanced through the introduction of fluorine groups. Ultra-low dielectric constant and high-temperature resistance can be achieved by employing rigid monomers and porous structures. Furthermore, the incorporation of fillers such as graphene and boron nitride can endow the composite materials with high thermal conductivity, excellent EMI shielding efficiency, and improved mechanical properties. Finally, we discuss representative applications of polyimide and composites in electronic device packaging, EMI shielding, and thermal management systems, providing insights into future development directions. Full article