Search Results (590)

Perfluorosulfonic acid (PFSA) membranes suffer from severe conductivity decay caused by dehydration at elevated temperatures, hindering their application in medium- to high-temperature proton exchange membrane fuel cells (MHT-PEMFCs). To address this, Nafion/SiO₂ composite membranes with systematically varied filler contents were fabricated via a sol–gel-assisted casting strategy to enhance hydration stability and proton transport. Spectroscopic and microscopic analyses reveal a homogeneous nanoscale dispersion of SiO₂ within the Nafion matrix, along with strong interfacial hydrogen bonding between SiO₂ and sulfonic acid groups. These interactions effectively suppress polymer crystallinity and stabilize hydrated ionic domains. Thermogravimetric analysis confirms markedly improved water retention in the composite membranes at intermediate temperatures. Proton conductivity measurements at 50% relative humidity (RH) identify the Nafion/SiO₂-3 membrane as exhibiting optimal transport behavior, delivering the highest conductivity of 61.9 mS·cm⁻¹ at 120 °C and significantly improved conductivity retention compared to Nafion 117. Furthermore, single-cell tests under MHT-PEMFC conditions (120 °C, 50% RH) demonstrate the practical efficacy of these membrane-level enhancements, with the Nafion/SiO₂-3 membrane exhibiting an open-circuit voltage and peak power density 11.2% and 8.9% higher, respectively, than those of pristine Nafion under identical MEA fabrication and operating conditions. This study elucidates a clear structure–property–transport relationship in SiO₂-reinforced PFSA membranes, demonstrating that controlled inorganic incorporation is a robust strategy for extending the operational temperature window of PFSA-based proton exchange membranes toward device-level applications. Full article

Polymer composites reinforced with nanofillers, synthetic fibers, and inorganic fillers have progressed rapidly, yet recent advances remain fragmented across filler-specific studies and often lack unified mechanistic interpretation. This review addresses this gap by presenting an interphase-centric, mechanism-driven framework linking processing routes, dispersion and functionalization requirements, interphase formation, and the resulting structure–property relationships. Representative quantitative datasets and mechanistic schematics are integrated to rationalize nonlinear mechanical reinforcement, percolation-controlled electrical/thermal transport, and thermal stabilization and barrier effects across major filler families. The review highlights how reinforcement efficiency is governed primarily by interfacial adhesion, filler connectivity, and processing-induced microstructural evolution rather than filler loading alone. Key challenges limiting scalability are critically discussed, including dispersion reproducibility, viscosity and processability constraints, interphase durability, and recycling compatibility. Finally, mechanism-based design rules and future outlook directions are provided to guide the development of high-performance, multifunctional, and sustainability-oriented polymer composite systems. Full article

A low-permeability, high salinity reservoir entered the high-water-cut and high recovery degree stage in the middle and late stages of development, and it is difficult to tap the potential of water flooding. The overall water flooding recovery of the developed low-permeability reservoir is low, and the produced water has high oil content, many granular impurities, and high inorganic salt content. The polymer–surfactant binary system was studied according to the reservoir conditions. The polymer acrylic acid/polyacrylamide/2-acryloylamino-2-methyl-1-propanesulfonic acid was selected by viscosity measurement. The viscosity stability of the polymer and the effect of the flooding system were evaluated, and the salt-tolerant surfactant sulfonated betaine + amides and coco composite system were screened, and the viscosity, interfacial tension, and displacement effect were evaluated. Finally, the polymer–surfactant binary flooding system was formed. The system has good compatibility, the interfacial tension can still be reduced to 10⁻³ mN/m at 40 °C and 23,800 mg/L, and the viscosity of the polymer solution increased by 5.8% upon addition of the surfactant. The composite system can improve the oil displacement efficiency by 21.19%. The results of a parallel core displacement experiment with a 3.91 permeability ratio show that the oil displacement efficiency can be improved by 19.96%. The system has good performance in low-permeability oilfields and can effectively displace crude oil, which is of great significance for the displacement of low-permeability heterogeneous reservoirs. Full article

Atherosclerosis remains a leading cause of cardiovascular mortality despite advances in pharmacological and interventional therapies. Current treatment approaches face limitations including systemic side effects, inadequate local drug delivery, and restenosis following vascular interventions. Gel-based technologies offer unique advantages through tunable mechanical properties, controlled degradation kinetics, high drug-loading capacity, and potential for stimuli-responsive therapeutic release. This review examines gel platforms across multiple scales and applications in atherosclerosis research and intervention. First, gel-based in vitro models are discussed. These include hydrogel matrices simulating plaque microenvironments, three-dimensional cellular culture platforms, and microfluidic organ-on-chip devices. These devices incorporate physiological flow to investigate disease mechanisms under controlled conditions. Second, therapeutic strategies are addressed through macroscopic gels for localized treatment. These encompass natural polymer-based, synthetic polymer-based, and composite formulations. Applications include stent coatings, adventitial injections, and catheter-delivered depots. Natural polymers often possess intrinsic biological activities including anti-inflammatory and immunomodulatory properties that may contribute to therapeutic effects. Third, nano- and microgels for systemic delivery are examined. These include polymer-based nanogels with stimuli-responsive drug release responding to oxidative stress, pH changes, and enzymatic activity characteristic of atherosclerotic lesions. Inorganic–organic composite nanogels incorporating paramagnetic contrast agents enable theranostic applications by combining therapy with imaging-guided treatment monitoring. Current challenges include manufacturing consistency, mechanical stability under physiological flow, long-term safety assessment, and regulatory pathway definition. Future opportunities are discussed in multi-functional integration, artificial intelligence-guided design, personalized formulations, and biomimetic approaches. Gel technologies demonstrate substantial potential to advance atherosclerosis management through improved spatial and temporal control over therapeutic interventions. Full article

The structural application of Fiber-Reinforced Polymers (FRP) is significantly hindered by their inherent thermal sensitivity. This paper presents a comprehensive review of the fire performance of FRP materials and FRP-concrete systems, spanning from material-scale degradation to structural-scale response. Distinct from previous studies, this review explicitly distinguishes between the fire behavior of internally reinforced FRP-reinforced concrete members and externally applied systems, including Externally Bonded Reinforcement (EBR) and Near-Surface Mounted (NSM) techniques. The thermal and mechanical degradation mechanisms of FRP constituents—specifically reinforcing fibers and polymer matrices—are first analyzed, with a focused discussion on the critical role of the glass transition temperature T_g. A detailed comparative analysis of the pros and cons of organic (epoxy-based) and inorganic (cementitious) binders is provided, elaborating on their respective bonding mechanisms and thermal stability under fire conditions. Furthermore, the effectiveness of various fire-protection strategies, such as external insulation systems, is evaluated. Synthesis of existing research indicates that while insulation thickness remains the dominant factor governing the fire survival time of EBR/NSM systems, the irreversible thermal degradation of polymer matrices poses a primary challenge for the post-fire recovery of FRP-reinforced structures. This review identifies critical research gaps and provides practical insights for the fire-safe design of FRP-concrete composite structures. Full article

Poly(ethylene oxide) (PEO)-based solid polymer electrolytes typically suffer from limited ionic conductivity at near-room temperature and often require inorganic reinforcement. Halide solid-state electrolytes such as Li₃InCl₆ (LIC) offer fast Li⁺ transport but are moisture-sensitive and typically require pressure-assisted densification. Here, we fabricate a flexible LIC–PEO composite electrolyte via slurry casting in acetonitrile with a small amount of LiPF₆ additive. The free-standing membrane delivers an ionic conductivity of 1.19 mS cm⁻¹ at 35 °C and an electrochemical stability window up to 5.15 V. Compared with pristine LIC, the composite shows improved moisture tolerance, and its conductivity can be recovered by mild heating after exposure. The electrolyte enables stable Li|LIC–PEO|Li cycling for >620 h and supports Li|LIC–PEO|NCM111 cells with capacity retentions of 84.2% after 300 cycles at 0.2 C and 80.6% after 150 cycles at 1.2 C (35 °C). Structural and surface analyses (XRD, SEM/EDX, XPS) elucidate the composite microstructure and interfacial chemistry. Full article

Electrospinning has emerged as a powerful technique for fabricating customised nanofibrous materials with integrated functional nanostructures, offering significant advantages for electrochemical energy applications. This review highlights recent advances in using electrospun nanofibres directly as active components in devices such as batteries, supercapacitors, and fuel cells. The emphasis is on the role of composite design, fibre morphology and surface chemistry in enhancing charge transport, catalytic activity and structural stability. Integrating carbon-based frameworks, conductive polymers, and inorganic nanostructures into electrospun matrices enables multifunctional behaviour and improves device performance. The resulting nanofibrous composite materials, often after heat treatment, can be used directly as electrodes or self-supporting layers, eliminating the need for additional processing steps such as size reduction or preparation of slurries and inks for creating functional nanofibre-based deposits. The importance of composite nanofibres as an emerging strategy for overcoming challenges related to scalability, long-term durability, and interface optimisation is also discussed. This review summarises the key results obtained to date and highlights the potential of electrospun nanofibres as scalable, high-performance materials for next-generation energy technologies, outlining future directions for their rational design and integration. Full article

In recent years, hybrid polymer/POSS (Polyhedral Oligomeric Silsesquioxane) systems have attracted particular attention, combining the advantages of organic and inorganic components. This paper reports on the thermal and thermo-oxidative degradation and weathering processes of these materials, as well as their impact on mechanical, chemical, and morphological properties. The paper discusses the physical and chemical changes occurring during degradation, the mechanisms of autoxidation, and the influence of environmental factors such as UV radiation, temperature, and humidity. Particular attention is paid to the role of POSS nanoparticles in polymer stabilization—their barrier function, free radical scavenging, and oxygen diffusion limitation. Methods for analyzing ageing processes are presented, including thermogravimetry coupled with infra-red spectroscopy (TG-FTIR), mechanical property testing, and yellowness index assessment. Material durability prediction models and their importance in designing composite lifespans in the context of the circular economy are also discussed. It is demonstrated that the appropriate type and concentration of POSS (typically 2–6 wt.%) can significantly improve polymer composites’ resistance to heat, radiation, and oxidizing agents, extending their service life and enabling more sustainable lifecycle management of products. Full article

Pigment gallstones represent a heterogeneous group of concretions, classically divided into black and brown types, whose morphology and microstructure offer critical clues about their underlying pathogenesis. Gallstone formation (lithogenesis) is a complex process triggered when the physicochemical equilibrium of bile is disrupted. Background/Objectives: The spicules observed on the surface of certain black pigment gallstones have traditionally been attributed to the branching capacity of cross-linked bilirubin polymers. However, a growing body of experimental and spectroscopic evidence suggests that inorganic calcium salts, particularly calcium carbonate and calcium phosphate, play a central role in the formation of the distinctive spiculated or “coral-like” architecture. Materials and Methods: In our study, we examined a case series of 1350 consecutive patients with gallstone disease, identifying 81 patients who presented with solitary black pigment stones. We systematically explored the association between high calcium content, specifically calcium carbonate, and the occurrence of spiculated morphology. Our analyses demonstrated a robust correlation between an elevated concentration of calcium carbonate and the presence of well-defined spicules. Results: These results support the hypothesis that mineral elements, rather than organic bilirubin polymers, act as crucial determinants of the peculiar crystalline structure observed in a significant subset of pigment stones. Spiculated stones, due to their small size and sharp projections, have a higher likelihood of migrating, increasing the risk of potentially life-threatening complications, such as acute cholangitis and gallstone pancreatitis. Conclusions: Our findings, consistent with recent advanced crystallographic analyses, underscore the importance of considering mineral composition in the diagnosis and management of cholelithiasis. Understanding the factors that drive calcium carbonate precipitation is essential for developing new preventive and therapeutic strategies, aiming to modulate bile chemistry and reduce the risk of calcium-driven lithogenesis. Full article

Exhaled breath analysis has gained considerable interest as a noninvasive diagnostic tool capable of detecting volatile organic compounds (VOCs) and inorganic gases that serve as biomarkers for various diseases. Polymer-based gas sensors have garnered significant attention due to their high sensitivity, room-temperature operation, excellent flexibility, and tunable chemical properties. This review comprehensively summarized recent advancements in polymer-based gas sensors for the detection of disease biomarkers in exhaled breath. The gas-sensing mechanism of polymers, along with novel gas-sensitive materials such as conductive polymers, polymer composites, and functionalized polymers was examined in detail. Moreover, key applications in diagnosing diseases, including asthma, chronic kidney disease, lung cancer, and diabetes, were highlighted through detecting specific biomarkers. Furthermore, current challenges related to sensor selectivity, stability, and interference from environmental humidity were discussed, and potential solutions were proposed. Future perspectives were offered on the development of next-generation polymer-based sensors, including the integration of machine learning for data analysis and the design of electronic-nose (e-nose) sensor arrays. Full article

The exploitation of deep hydrocarbon resources in extreme environments, particularly high-temperature and high-salinity (HTHS) carbonate reservoirs, poses unprecedented challenges for downhole plugging operations. This review provides a critical analysis of the development of gel-based plugging materials designed to withstand these harsh conditions. It systematically examines three primary material categories—polymers, inorganic composites, and nanocomposites—dissecting the fundamental relationships between their molecular architectures and their resulting performance, including the pervasive trade-offs between mechanical strength, stability, and controllable degradation. While highlighting promising advances, such as bio-derived polymers and self-healing mechanisms, the review explicitly identifies the limitations of current technologies, most notably their inadequate long-term durability under synergistic HTHS stress and lack of industrial scalability. This forward-looking perspective emphasizes the integration of nano-reinforcements and stimuli-responsive chemistries as a critical pathway toward achieving the next generation of high-performance, deployable, and environmentally considerate plugging materials, thereby ensuring the efficient and sustainable development of challenging oil and gas assets. Full article

Self-healing polymer-based coatings have emerged as a new generation of adaptive protective materials capable of restoring their structure and function after damage. This review provides a comprehensive analysis of current strategies enabling autonomous or externally triggered repair in polymeric films, including encapsulation, reversible chemistry, and microvascular network formation. Emphasis is placed on polymer–inorganic hybrid composites and vitrimeric systems, which integrate barrier protection with stimuli-responsive healing and recyclability. Comparative performance across different matrices—epoxy, polyurethane, silicone, and polyimine—is discussed in relation to corrosion protection and biomedical interfaces. The review also highlights how dynamic covalent and supramolecular interactions in hydrogels enable self-repair under physiological conditions. Recent advances demonstrate that tailoring interfacial compatibility, healing kinetics, and trigger specificity can achieve repeatable, multi-cycle recovery of both mechanical integrity and functional performance. A representative selection of published patents is also shown to illustrate recent technological advancements in the field. Finally, key challenges are identified in standardizing evaluation protocols, ensuring long-term stability, and scaling sustainable manufacturing. Collectively, these developments illustrate the growing maturity of self-healing polymer coatings as multifunctional materials bridging engineering, environmental, and biomedical applications. Full article

Solid-state batteries (SSBs) are regarded as one of the most promising next-generation energy storage technologies due to their high energy density and improved safety. To achieve this goal, the development of solid-state electrolytes with high ionic conductivity and low interfacial resistance is essential. In recent years, composite polymer electrolytes (CPEs) have garnered extensive attention due to their ability to combine the intrinsic flexibility of polymers with the enhanced ionic conductivity and mechanical robustness provided by inorganic fillers. Metal–organic frameworks (MOFs), characterized by tunable pore structures, high surface areas, and excellent thermal and mechanical stability, are considered ideal fillers for constructing MOF–polymer composite electrolytes (MPCEs). This review summarizes the performance enhancement mechanisms of MPCEs and strategies for electrode–electrolyte interface stability. First, the primary preparation methods of MPCEs are introduced. Subsequently, the roles of MOFs in regulating ionic transport, suppressing dendrite growth, improving electrochemical stability, and optimizing the solid electrolyte interphase (SEI) layer are discussed. In addition, various interface engineering strategies are highlighted, including in situ polymerization of the polymer matrix, in situ growth of MOF fillers, integration of liquid plasticizers forming gel-like ionic conductor, and design of composite electrode to enhance interfacial compatibility and stability. Finally, the significant challenges and future research directions of MPCEs are outlined. This review provides valuable insights into the rational design of MPCEs and offers guidance for the development and practical application of high-performance SSBs. Full article

The growing demand for sustainable, high-performance, and structurally reliable construction materials has intensified research on natural fibre-reinforced composites (NFCs). Among these, hemp stands out due to its high cellulose content, low density, excellent tensile strength, and renewability, making it a promising reinforcement for cementitious and other inorganic matrices, including lime- and geopolymer-based systems. This review focuses exclusively on structural and civil engineering applications, while polymer-based composites are mentioned only for comparative context regarding adhesion and durability. A comprehensive bibliometric and technical analysis was conducted to evaluate the effectiveness of hemp fibre treatment methods in improving fibre–matrix adhesion, mechanical performance, and long-term durability. A systematic search covering major scientific databases from 2014 to 2024 identified global research trends, key treatment techniques, and their performance outcomes. Both chemical (alkaline, silane, acetylation, alkyl ketene dimer—AKD) and physical (plasma, ozone) modification strategies were critically assessed for adhesion, mechanical strength, hydrophobicity, and resistance to environmental cycling. Quantitative results indicate that combined alkaline–AKD treatments produce the most consistent improvement, increasing compressive strength by approximately 30% and flexural strength by up to 25% compared with untreated composites. Physical surface treatments were also found to enhance roughness and interfacial bonding without degrading fibre integrity. Unlike previous reviews that address natural fibres in general, this article specifically targets hemp fibre treatments for inorganic matrices, correlating modification mechanisms with the structural performance indicators relevant to civil engineering. By integrating bibliometric mapping of research evolution, keyword networks, and technological gaps, this review provides a quantitative and engineering-oriented synthesis that highlights its original contribution to sustainable and resilient construction materials. The findings emphasise the need for standardised testing protocols and performance-based evaluations to enable the broader structural application of hemp-based composites in modern construction. Full article

Sulfonated poly(ether ether ketone) (SPEEK) is one of the most studied ionic polymers for polymer electrolyte membranes (PEMs) in fuel cells (PEMFCs). To improve its proton conductivity, novel SPEEK/praseodymium-doped zinc spinel ferrite composite membranes of 130–170 μm thickness were prepared via ultrasound-assisted dispersion of various proportions of synthesized doped ferrite nanoparticles into the polymer solution, followed by a simple solution-casting method. The morphology (as observed by SEM and confirmed by DMA) and the conducted physical and chemical tests typical for PEMs, such as water uptake (32–44% at 80 °C), ionic exchange capacity (1.67–1.80 mEq/g), chemical (around 1% loss in Fenton reagent after 24 h), thermal stability (up to 190 °C) and tensile strength (39–50 MPa), were proven to depend on the content of inorganic filler in the composite (up to 5%). The proton conductivity of composite membranes (0.21–2.82 × 10⁻² S/cm at 80 °C) was assessed by broadband dielectric spectroscopy. The membrane with a content of 0.25 wt.% ZnFe_1.96Pr_0.04O₄ showed the best proton conductivity (3.41 × 10⁻² S/cm at 60 °C), as compared to 1.60 × 10⁻² S/cm for Nafion117 measured under the same conditions, demonstrating its suitability as a PEM for fuel cell applications. Full article