Search Results (3,759)

Environmental pollution constitutes an increasingly complex global challenge, largely driven by industrial expansion and the consequent release of toxic species such as Cd²⁺, Pb²⁺, Cu²⁺, Hg²⁺, Fe³⁺, As³⁺, and Rh³⁺ into natural ecosystems. These contaminants pose significant risks to environmental integrity and public health, motivating the development of analytical technologies capable of sensitive, selective, and reliable detection. In this context, graphene-based electrochemical sensors have emerged as versatile platforms for monitoring a broad range of analytes, particularly in environmental applications involving heavy-metal detection. The intrinsic physicochemical properties of graphene derivatives have enabled low detection limits, rapid response times, and tunable selectivity. Despite analytical advances, critical challenges persist regarding operational stability in complex matrices, inter-batch reproducibility, and robustness to interfering species, which continue to hinder large-scale deployment and real-world applicability. However, challenges remain regarding stability and performance in complex arrays, reproducibility, and resistance to interference, necessitating innovative strategies for functionalization and molecular recognition. This review article establishes a comparative framework based on functionalization strategies (covalent, non-covalent, and hybrid), the chemical nature of graphene (GO, rGO, and doping), and various types of polymers (conductors and insulators), using statistical metrics such as the limit of detection (LOD), linear range, working potential, stability, and interferences, employing a bibliometric analysis using the PRISMA 2020 methodology. This comparative framework enables analysis and explanation of performance trends, and the generation of design and functionalization recommendations for versatile applications, including criteria for reproducibility and sustainability. Full article

Seismocardiography (SCG) is a promising noninvasive modality for cardiovascular monitoring. By capturing subtle chest wall vibrations induced by the mechanical pumping activity of the heart at the body surface, SCG is of considerable value for blood pressure-related cardiovascular risk assessment and cardiac function monitoring. However, continuous SCG monitoring in daily life settings still relies predominantly on rigid accelerometers, and reports on flexible acquisition systems remain scarce. This is mainly because SCG signals are characterized by low frequency, low amplitude, and high sensitivity to the sensor-skin interface, requiring the sensor to achieve stable, high-fidelity acquisition of weak chest wall mechanical vibrations while maintaining conformal contact and wearing comfort. To address this challenge, this study proposes a flexible pressure sensor based on the triboelectric effect. The sensor adopts a single-electrode contact-separation structure and is composed of a polymer material capable of achieving a high negative charge density and a nickel foil electrode. The sensor exhibits a sensitivity of 3.76 V/N within a small force range of 0–200 mN, shows good frequency response over the 0.5–25 Hz band, and maintains stable output after approximately 5300 cycles. The sensor was attached to the lower-middle segment of the sternum to capture weak vibration signals generated by cardiac mechanical activity and transmitted through the chest wall, thereby enabling continuous SCG monitoring. This study presents a feasible approach for flexible SCG acquisition in daily life scenarios and provides experimental evidence supporting the application of flexible sensors in home-based health monitoring. Full article

Manganese dioxide (MnO₂) modified biochar catalysts derived from biomass and waste polymer feedstocks were synthesized and evaluated as heterogeneous Fenton-like catalysts for solar-driven degradation of Rhodamine B (RhB) in aqueous systems. Biochars produced from maple wood and plastic waste (high-density polyethylene) provided porous carbon matrices with oxygen-rich surface functionalities that enabled effective MnO₂ loading and catalytic activity. Photocatalytic experiments conducted under real sunlight using a solar-collector reactor demonstrated faster RhB degradation compared to a conventional ultraviolet (UV) system, confirming the advantage of solar-driven operation. Complete RhB removal was achieved at initial concentrations of 100–300 ppm, whereas higher dye concentrations (500 ppm) exceeded the catalytic capacity within the tested reaction time. Kinetic analysis revealed catalyst-dependent reaction behaviors, indicating that degradation pathways were strongly influenced by the biopolymer-derived carbon structure and MnO₂ dispersion. Degradation efficiency was correlated with solar irradiance and reactor temperature, with higher UV index conditions enhancing catalytic performance. Reusability tests showed that the catalysts remained active over multiple cycles, although gradual decreases in reaction rates and catalyst recovery were observed. These results demonstrate the potential of biopolymer-derived carbon materials as effective solar-driven catalysts for wastewater treatment applications. Full article

A non-contact laser polishing method for additively manufactured polymer components with complex three-dimensional geometries is presented, employing a 6-axis robotic system. Robot-guided sample orientation, a quasi-top-hat scanning strategy, and closed-loop temperature control are combined to address curved geometries. On Selective Laser Sintering (SLS)-manufactured Polyamide 12 (PA12) tensile samples with three build orientations and two thicknesses, laser polishing yields up to a 15% increase in tensile strength (Rm) and a 50% increase in elongation at break (A). For 45°-built 5 mm samples, Rm increases from 31.53 MPa to 36.33 MPa and A from 6.52% to 9.8%, approaching the tensile strength reported for optimally oriented SLS-printed PA12 Smooth samples of the same grade. For convex–concave PA12 demonstrators, areal roughness (Sa) on convex surfaces is reduced from 33.6 µm to 2.7 µm (approximately 92%) and the high-pass-filtered micro-roughness (Sa_HP) on concave surfaces by 98.2% to 0.15 µm. For Fused Deposition Modeling (FDM)-printed Polyaryletherketone (PAEK) samples, Sa is reduced from 28.35 µm to 4.1 µm and Sa_HP from 15.98 µm to 0.23 µm (98.6%), despite the high melting temperature and anisotropic raster topography. These results demonstrate that robotic laser polishing constitutes a viable post-processing approach for functionally demanding polymer applications. Full article

Photodetectors have undergone widespread, gradual application. Correlation detectors with varying properties are used in diverse fields. This review systematically summarizes the principles, properties, and applications of various photoelectric detectors reported in the past five years, compares their similarities and differences, and further discusses their respective advantages and disadvantages, applicable scenarios, and development prospects. The review covers self-powered detectors, which are very convenient and widely used in consumer electronics and portable wearable devices, and discusses the structural design and photoelectric performance of devices based on P–N junctions, perovskites, silicon–polymer hybrid composites, graphene, hybrid graphene/PbS quantum dot systems, and other novel material architectures. Compound photoelectric detectors enable multifunctional integration and intellectualization. At the same time, their high sensitivity and broad-spectrum response can expand the detection wavelength range to cover the ultraviolet, visible, and infrared bands and enhance the detection of weak optical signals. Finally, this review summarizes current challenges, including cumbersome fabrication processes, susceptibility of detection stability to environmental interference, and limited functionality, and focuses on recent advances in various photodetectors, where breakthroughs are expected. Full article

With the rapid advancement of artificial intelligence and wearable technologies, the demand for soft, multifunctional electronic materials has grown substantially. Hydrogels have emerged as a promising platform due to their intrinsic softness, stretchability, and biocompatibility. Among them, cellulose-based conductive hydrogels uniquely integrate the sustainability of natural polymers with tunable electrical functionality, offering significant potential for flexible and biointegrated electronics. This review provides a comprehensive and critical perspective on the recent progress in cellulose-based conductive hydrogels. We systematically summarize key design strategies, including physical and chemical crosslinking and interpenetrating network engineering. More importantly, we present a comparative analysis of distinct conductive mechanisms, including ionic conduction, conductive polymers, metallic nanostructures, and carbon-based fillers, highlighting the inherent trade-offs among electrical conductivity, mechanical robustness, and environmental stability. Emerging applications in flexible electronics, energy storage, bioelectronics, and self-powered systems are discussed through structure–property relationships. Finally, we outline current challenges and future directions, emphasizing multifunctional integration, scalable fabrication, and long-term operational stability, thereby providing a framework for the rational design of next-generation sustainable electronic materials. Full article

High-efficiency energy storage technologies have become particularly crucial with the ever-increasing demand for energy in recent years. Research on polymer nanocomposite dielectric materials has emerged as a prominent focus. Particularly, there is an urgent demand for the development of advanced dielectric film materials that exhibit superior energy storage performance over a wide temperature range. To this end, this study aims to investigate the effect of the molecular weight of reduced polyaniline (R-PANI) on the dielectric properties of all-organic composite films based on high-temperature-resistant polyetherimide (PEI). All-organic R-PANI/PEI composite films were fabricated by blending PEI matrix with R-PANI of varying molecular weights. Through combined density functional theory (DFT) calculations and experimental measurements, the blocking mechanism of R-PANI on charge carrier migration within the composite films was elucidated, showing a significant enhancement in the discharge energy density of PEI polymers while maintaining high charge–discharge efficiency. With charge–discharge efficiency maintained above 95%, R-PANI3/PEI achieved a discharge energy density of 2.36 J cm⁻³ at room temperature, nearly double that of pristine PEI (1.2 J cm⁻³). At 150 °C, the 1.0 wt% R-PANI3/PEI composite film retained a discharge energy density of 2.27 J cm⁻³ with a charge–discharge efficiency of 89.2%, outperforming pure PEI (1.1 J cm⁻³, 85.1%). These findings provide a new strategy for the design of all-organic composite dielectric films and demonstrate the potential of R-PANI in the application of high-performance capacitors and electrical energy storage. Full article

Micro- and nanoplastic pollution poses an emerging challenge for aquatic environments, driving the need for efficient and scalable removal strategies. Functional polymeric materials (FPMs) have emerged as a versatile platform to address this issue, owing to their tunable chemical composition, structural diversity, and ability to promote multiple removal mechanisms, including adsorption, filtration, and coagulation/flocculation. This review provides an overview of recent advances in polymer-based strategies for the removal of micro- and nanoplastics, with emphasis on material design, interaction mechanisms, and process performance. A broad range of materials, including natural hydrogels, polysaccharide aerogels, synthetic polymer composites, magnetic hybrids, and metal–organic frameworks (MOFs)–polymer systems, have demonstrated high removal efficiencies through electrostatic interactions, hydrogen bonding, hydrophobic effects, π–π stacking, and physical entrapment. Removal performance is strongly influenced by surface functionalization, porosity, surface area, and polymer network architecture, enabling targeted design for specific particle types and water matrices. Hybrid and multifunctional materials further enhance capacity and reusability, while natural polymers offer sustainable alternatives. Despite these advances, challenges remain in standardization, scalability, long-term stability, fouling resistance, and economic feasibility under realistic environmental conditions. Future research should focus on sustainable, multi-target, and scalable FPMs, integrating hybrid architectures, stimuli-responsive functionalities, and bioinspired design strategies. Particular attention should be given to mechanistic studies under environmentally relevant conditions and the establishment of structure–property design criteria to enable efficient removal of heterogeneous MPs/NPs mixtures. Overall, functional polymeric materials represent a flexible and high-performance platform for mitigating micro- and nanoplastic contamination, although their successful implementation will depend on bridging the gap between laboratory-scale performance and real-world water treatment applications. Full article

Superhydrophobic coatings are regarded as a promising passive anti-icing strategy; however, their practical engineering application, particularly in electrical insulation, is severely hindered by the performance deterioration caused by mechanical damage and a lack of theoretical understanding of microscopic ice adhesion mechanisms. In this study, a layered polymer composite coating was designed to resolve the trade-off between abrasion resistance and low ice adhesion. The chemistry of the coating relies on a synergistic “primer–topcoat” design: the primer consists of an epoxy resin matrix chemically modified by amino silicone oil to lower its surface energy and improve toughness, while the topcoat features hierarchical SiO₂ clusters functionalized with hexamethyldisilazane (HMDS) and silane coupling agents. This architecture was fabricated via a controllable layer-by-layer spraying method. Systematic investigations revealed that the hierarchical micro/nanostructure, composed of microscale protrusions and nanoscale SiO₂ clusters, provides excellent superhydrophobicity (contact angle of 155.2°, sliding angle of 2°). Crucially, the crosslinked polymer network and stable siloxane (Si-O-Si) covalent bonding ensure that the coating maintains its functionality after a cumulative sand impact of 3 kg, demonstrating superior mechanical durability. Furthermore, differentiated theoretical models for ice adhesion in Cassie–Baxter and Wenzel states were established based on intermolecular interactions, identifying that maintaining a stable Cassie–Baxter state is key to reducing adhesion. This study offers a robust approach to balancing functionality and durability in polymer composites through synergistic structural design, providing both a scalable fabrication strategy and a quantitative theoretical framework for understanding interfacial ice adhesion. Full article

Urushiol, the key component of natural lacquer, is emerging as a versatile bio-based phenolic platform for advanced polymer systems. Its unique catechol structure, combined with an unsaturated aliphatic side chain, provides multiple reactive sites, enabling diverse chemical pathways and tunable network architectures. This review presents a systematic analysis of urushiol-based materials within a “structure–reaction–property–application” framework. The intrinsic reactivity of urushiol, including oxidative polymerization, dynamic covalent bonding, and metal–phenolic coordination, is correlated with the formation of crosslinked networks exhibiting controllable mechanical properties, strong interfacial adhesion, and stimuli responsiveness. Recent advances in functional coatings, self-healing and reversible polymers, bioactive materials, and cultural heritage conservation are highlighted. Special emphasis is placed on dynamic network design and low-sensitization strategies to overcome limitations of traditional lacquer systems. Finally, key challenges and future directions toward controllable curing, structure–property relationships, and sustainable material design are discussed, positioning urushiol as a bridge between traditional materials and next-generation functional polymers. Full article

Due to biodegradability, functionalization, and sustained release, polymer-based films are widely used in different industries. This study explores a bioactive emulsion-based film obtained using high-methoxy pectin (HMP), Origanum onites L. essential oil, and a hydroalcoholic extract of Thymus vulgaris L., prepared using various emulsion recipes. The emulsions obtained were applied to cellulose supports intended for topical applications. Bioactive textiles were analyzed using SEM-EDS elemental mapping, ATR FT-IR spectroscopy, biocompatibility assessment, antimicrobial activity assays, and analysis of comfort indices. SEM images of textile supports treated with bioactive emulsions confirmed the creation of a film surface and that the homogeneity of the film increases with increasing amount of glycerin, which acts as a plasticizer. Infrared spectra combined with their second derivatives and PCA indicate the presence of oregano essential oil, thyme extract, and pectin on the surface of the cotton. The biocompatibility evaluation of functionalized cotton supports revealed minimal cytotoxic effects on HaCaT human keratinocytes after 24 h of exposure. The results of the analyses showed that bioactive textile supports also exhibit antimicrobial activity. Therefore, the active emulsions with pectin, oregano essential oil, and hydroalcoholic extract of thyme provide biocompatible and antimicrobial active films by applying on cellulosic supports. Full article

Cellulose-derived gel films are promising matrices for the immobilization and delivery of beneficial microorganisms in sustainable plant protection. This study evaluated the effects of polymer molecular weight and chemical structure on the physicochemical properties and biocontrol performance of hydroxyethyl cellulose (HEC) films of low, medium, and high molecular weight, as well as sodium carboxymethyl cellulose (CMC-Na), loaded with Bacillus subtilis. The films were characterized in terms of morphology, swelling behavior, mechanical properties, microbial viability, and antifungal activity against Fusarium avenaceum and Alternaria solani. Increasing HEC molecular weight produced progressively denser and more homogeneous gel networks, resulting in improved structural integrity, whereas CMC-Na formed dense but less stable networks. Swelling studies at pH 4, 7, and 9 showed high water uptake for all HEC systems, with enhanced structural stability observed in high-molecular-weight films, whereas CMC-Na dissolved rapidly under all conditions. Mechanical testing further confirmed that increasing molecular weight enhanced stiffness and tensile strength but reduced flexibility. Immobilized in gel matrices, B. subtilis remained viable after 12 months of storage and rapidly reactivated after rehydration. All biohybrid films inhibited fungal growth, with stronger formulation-dependent responses against F. avenaceum than against A. solani. In general, polymer molecular weight and structure were identified as key parameters controlling network organization, hydration behavior, mechanical performance, and biological functionality. These findings highlight the potential of cellulose-derived gel matrices as tunable carriers for microbial biocontrol applications. Full article

Conductive polymer microcellular foamed materials are a type of functional composite that combines lightweight cell structures with controllable conductivity. Their core feature lies in regulating the cell structure of the material through microcellular foaming technology, along with the introduction of conductive fillers or the intrinsic conductivity of the polymer, to achieve enhanced electrical performance. This paper systematically reviews conductive polymers and their microcellular foamed materials, highlighting research progress in foaming mechanisms, preparation processes, and functional applications. It first analyzes the key mechanisms of bubble nucleation, growth, and stabilization during the microcellular foaming of conductive polymers. Then, it elaborates on the research status and functional mechanisms of these materials in three typical application scenarios: electromagnetic shielding, flexible sensors, and thermal management. Finally, it outlines the future development directions of conductive polymer microcellular foamed materials in multifunctional integration, green fabrication, and intelligent applications, aiming to provide theoretical guidance and technical pathways for future research. Full article

This study examined how the extraction medium used to obtain Quercus robur extracts influenced the properties of electrospun poly(vinyl alcohol) (PVA) mats intended for potential active packaging applications. Extracts prepared with 50% ethanol and with a choline chloride:lactic acid:water system were incorporated into PVA spinning solutions, and their effects on solution properties, fiber morphology, thermal behavior, crosslinking response, and polyphenol release were evaluated. The type of extraction medium affected both the electrospinning process and the structure of the resulting materials. Ethanol-derived extracts reduced solution viscosity and promoted the formation of thinner fibers, whereas systems containing the choline chloride:lactic acid:water-derived extract showed higher conductivity and lower electrospinning stability. Crosslinking with tannic acid in water led to the collapse of the fibrous structure, while ethanolic tannic acid treatment preserved the nanofibrous morphology more effectively. FTIR analysis indicated differences in intermolecular interactions within the polymer matrix, consistent with the observed changes in structural stability and release behavior. Thermal analysis showed that ethanol-derived extracts lowered the thermal stability of the PVA matrix, whereas the choline chloride:lactic acid:water-derived system altered the degradation pathway and increased the amount of solid residue formed during heating. Release studies demonstrated a rapid burst release for ethanol-based mats and a more sustained release profile for mats containing the choline chloride:lactic acid:water-derived extract. Selected extract-containing and ethanol–tannic acid-crosslinked mats also showed antibacterial activity against Staphylococcus aureus. The results showed that the extraction medium significantly affected polymer–extract interactions and the functional properties of electrospun PVA mats. At the same time, the conclusions refer specifically to the tested solvent systems, and broader generalization to other natural deep eutectic solvent-type formulations requires further comparative studies. Full article

Traditional polymer-dispersed liquid crystal (PDLC) faces limitations in smart dimming applications due to high driving voltage and poor high-temperature stability. In this study, a high-birefringence liquid crystal (QYPDLC-901) was used to prepare PDLC films with liquid crystal contents ranging from 72 wt% to 80 wt%, achieved through synergistic regulation of a low-functional acrylic polymer system and a low-intensity curing process. The effects of liquid crystal content, cell gap, and temperature on electro-optical properties were systematically investigated. Optimal performance was obtained at a liquid crystal content of 77 wt%, with a low threshold voltage of 2.9 V, saturation voltage of 7 V, fast response (rise time 4.2 ms, decay time 47 ms), and a favorable balance between high on-state and low off-state transmittance. Microstructural analysis revealed that the superior performance results from uniform droplet dispersion and low interfacial energy. Furthermore, the PDLC exhibited excellent switching stability from 23 °C to 90 °C, maintaining a maximum transmittance of 93% at 90 °C, with increases of only 0.4 V in threshold voltage and 0.1 V in saturation voltage. This study provides an experimental basis for designing smart dimming devices suitable for low-voltage driving and extreme environments. Full article