Search Results (1,158)

The ionic liquids are increasingly used as versatile media capable of reshaping the electrochemical environment for hydrogen production. Their wide electrochemical windows, thermal stability, and customizable solvation structures enable these liquids to tailor the electrode–electrolyte interface in such a way that the traditional alkaline and polymer-membrane systems cannot. These features allow for reductions in the hydrogen evolution overpotentials, improved catalyst stability, and effective suppression of gas crossover, positioning the ionic liquids as promising components for advanced electrolysis systems. Despite these benefits, their broader deployment remains constrained by certain challenges. The elevated viscosity and associated mass-transport limitations complicate the cell design and energy efficiency, whereas the cost and long-term stability of many ionic liquids limit their competitiveness in industrial hydrogen production. Also, the hydrolysable anions and other reactive species increase the burden, particularly in environments where moisture and anodic potential are present. As a result, the ionic liquids electrolysis has its most promising prospects in niche and hybrid configurations like the renewable integrated systems and configurations where the tailored interfacial chemistry and long operational lifetimes outweigh the investment cost and maintenance requirements. Future progress will depend on the development of greener, task-specific ionic liquids with improved stability and lower synthesis costs, alongside hybrid electrolyte designs that balance the unique interfacial benefits of ionic liquids with the practicality of aqueous systems. Advancing these materials from laboratory research to large-scale sustainable hydrogen production will require coordinated advances in the materials compatibility, device and infrastructural architecture, and techno-economic optimization. Full article

Chiral and racemic forms of a pyridyl ligand (R-L and rac-L, respectively), containing urea groups at their core and synthesised by the condensation of 3-aminopyridine and α-methylbenzylisocyante, were incorporated into silver complexes. The resulting species depend on the enantiopurity of the ligand alongside an influence from the counter-anion. The enantiopure ligand generated isomorphous, one-dimensional polymeric compounds [Ag(R-L)X] (where X = NO₃, CF₃SO₃) or [Ag(R-L)]X (where X = BF₄, PF₆). The polymeric chains, connected by N and O coordination of the ligands, have outwards facing urea groups that form hydrogen bonds to the counter-anions, which play little role in determining the overall structure. Despite all syntheses containing an excess of Ag(I) salt, the racemic ligand formed only discrete complexes of [Ag(rac-L)₂]⁺ in the presence of each of the above anions. Three of these complexes contain ligands of the same chirality (i.e., complexes with R,R and S,S ligand pairs within the centrosymmetric structures) with only the PF₆-containing compound being different. The anions play a role in dictating the structure of hydrogen-bonded chains, although PF₆⁻ is unique with urea···urea interactions present between complexes. Overall, this system highlights the nuances associated with predicting the structure, and even speciation, of related chiral/achiral systems in addition to influences of counter-anions on structural motifs. Full article

This study investigates the rational design of a dinuclear zinc(II) coordination polymer, (C₃₆H₃₄Br₂N₈O₄S₂Zn₂), to explore how halogen substitution and ligand choice modulate structural architecture, contributing to the development of functional coordination polymers with tailored properties. The complex was synthesized from a bromo-substituted semicarbazone Schiff base ligand (L1) and a rigid bipyridine linker (L2) under solvothermal conditions, and its structure was elucidated using single-crystal X-ray diffraction (SCXRD), complemented by characterization via powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), and infrared (IR) spectroscopy. Crystallographic analysis reveals that the complex crystallizes in the triclinic space group P-1, forming discrete dinuclear units where each Zn(II) center adopts a distorted square–pyramidal geometry; these units are extended into one-dimensional chains by bridging L2 ligands and further assembled into a three-dimensional supramolecular network through hydrogen-bonding interactions. PXRD confirms the high phase purity of the bulk material, TGA indicates notable thermal stability up to 130 °C, and IR spectroscopy validates the coordination modes and hydrogen-bonding network. This work elucidates the critical role of the bromo substituent and rigid ancillary ligands in modulating the solid-state structure of the zinc(II) complex. The revealed structure-directing principles provide a valuable reference for the rational design of functional coordination polymers. Full article

In nature, avian species achieve remarkable aerodynamic efficiency by seamlessly coordinating flexible soft tissues to create continuous, adaptive wing surfaces, significantly minimizing drag and eliminating parasitic turbulence. Traditional shape morphing systems rely on bulky mechanical linkages that add excessive weight, often offsetting aerodynamic gains. The integration of soft active materials has emerged as a transformative solution for weight-efficient, seamless actuation. However, a significant disconnect remains between laboratory-scale research and practical aerospace implementation. This perspective evaluates three prominent classes of soft active materials, shape memory polymers (SMPs), dielectric elastomers (DEAs), and liquid crystal elastomers (LCEs), analyzing their actuation mechanisms and comparing their performance in load-bearing, response bandwidth, and energy efficiency. By addressing the necessity of structural-material synergy, we discuss the potential solution for bridging the gap between material synthesis and system-level flight performance to enable the successful deployment of soft active materials in future aerial platforms. Full article

Polyolefins are widely used polymers, with an annual global production of hundreds of millions of tons. Because they are the simplest hydrocarbon polymers, their intrinsic non-polar properties limit further applications. Coordination–insertion copolymerization of an olefin with other monomers, mediated by transition metal catalysts, is the most efficient way to synthesize polar and multi-functionalized polyolefins with enhanced material performance. Previous reviews have primarily focused on the structural design of a specific catalyst or on binary copolymerization of an olefin with a particular comonomer. However, the transition-metal-catalyzed ternary coordination–insertion polymerization of olefin monomers remains scarce. In this contribution, early transition-metal catalysts, such as Ti, Zr, Hf, and V, are employed for the terpolymerization of all-hydrocarbon or non-polar monomers to access advanced polyolefin materials with high performance. By contrast, late transition metal catalysts based on Ni and Pd, as well as rare-earth metal catalysts ligated by Sc and Y, enable the terpolymerization of olefins with a variety of heteroatom-containing monomers. Their strong tolerance empowers the development of polyolefins with multiple functionalities, thereby distinguishing these systems. The catalyst structure, catalytic process, and mechanism studies are summarized, along with the microstructure and functionality of the polymerization products, by classifying the types of termonomers employed. Full article

Due to the non-polar and chemically inert nature of carbon fiber surfaces, the interfacial bonding strength between carbon fibers and norbornene-polyimide (PI-NA) resin matrix is relatively weak. To address this issue, this study constructed a composite coating on the carbon fiber surface and proposed a novel method to build robust interfaces based on multiple interfacial interactions, thereby effectively enhancing the interfacial properties between carbon fibers and PI-NA resin. Inspired by mussel adhesive proteins, this study established a multi-level synergistic interfacial reinforcement system by sequentially constructing a C-PEI@OPDA coating, in situ growing zinc oxide nanorods (ZW) arrays, and grafting 3-mercaptopropyltrimethoxysilane (MPS) onto carbon fiber surfaces. The C-PEI@OPDA coating, rich in amino (–NH₂) and hydroxyl groups (–OH), enhanced adhesion to carbon fibers and adsorbed Zn²⁺ via coordination interactions to provide nucleation sites for ZW growth. Meanwhile, the active hydrogen in the coating promoted the crosslinking of PI-NA resin, thereby increasing the resin crosslinking density in the interfacial region. The vertically aligned ZW significantly increased surface roughness, enhanced mechanical interlocking effects, and provided secondary reaction sites for MPS grafting. The thiol groups (–SH) in MPS formed covalent bonds with PI-NA resin through thiol-ene click reactions, further strengthening interfacial bonding. The results showed that the ILSS, IFSS, and flexural strength of C-PEI@OPDA/ZW/MPS modified carbon fiber composites reached 75.15 MPa, 102.93 MPa, and 1735.56 MPa, representing improvements of 39.09%, 48.79%, and 31.16%, respectively. This study effectively enhanced the carbon fiber-reinforced polymer composites interfacial bonding strength through the synergistic effects of hydrogen bonding, mechanical interlocking, chemical bonding, and increased resin crosslinking density. Full article

Development of new polymers that cannot be achieved by using conventional catalysts has been the central research objective, and copolymerization is an effective strategy to modify the materials’ (thermal, physical, mechanical and electronic) properties. Modified half-titanocenes, Cp’TiX₂(Y) (Cp’ = cyclopentadienyl, X = Cl, Me, etc, Y = anionic donor such as phenoxide, ketimide, amidinate, etc.), are known to be effective catalysts. This review introduces several selected efforts for efficient synthesis of ethylene copolymers containing cyclic olefins, biobased conjugated dienes, and disubstituted α-olefins, including the effect of cocatalysts. Moreover, here we introduce an analysis using XAS (X-ray absorption spectroscopy), which has been recognized as a powerful method providing direct information on the catalytically active species, such as coordination numbers and the distances of the coordinated atoms as well as oxidation state and the geometry of the metal centre in catalyst solution. Full article

In agriculture, soil amendments like compost, manure, superabsorbent polymers (SAP) and biochar (BC) are already in use to mitigate the effects of water shortage and to obtain a higher yield and survivability. The present study focuses on the impact of BC and SAP under moderate and reduced soil water content (SWC) on the physiological and biochemical response of Chenopodium quinoa Willd. (cv. UDEC-5), a naturally drought-resistant and strategic crop in arid regions, with the aim of further improving its resilience and biomass production. Plants were grown in the presence or absence (control) of SAP (1% or 0.1% g/100 g SAP) or BC (3% g/100 g BC) by taking into account the smallest possible amount of irrigation necessary for optimal growth of the control. Sixty-five days after sowing, the reduced watering approaches started. The irrigation amount was reduced slowly until plants without any amendment showed a significant reduction in CO₂/H₂O gas exchange and further significant changes in 23 morphological, physiological and biochemical symptoms of water shortage. Each amendment already caused individual plant response in wet conditions: The soil amendments of SAP (1% and 0.1%) and BC had no significant effect on biomass production but caused changes in PS I (portion of oxidized and open centers in PS I), the C/N ratio and N content. The addition of SAP (0.1% and 1%) led to a decrease in gH⁺, ECStmAu ^× gH⁺, R_D, R_L, the C_i/C_atm ratio and ETR/A_gross ratio and to an increase in water use efficiency (WUE), especially in the 0.1% SAP treatment. In moderate conditions, 0.1% SAP and 3% BC caused a significant increase in both the LOP and C/N ratio. In the moderate treatments, the application of 0.1% SAP promoted an increased A_net, while 3% BC promoted a significant reduction in malondialdehyde (MDA). The results of the present quinoa experiment indicate the drought avoidance mechanism of the control under low SWC. The reduced transpiration led to increased WUE due to the efficient use of the substomatal CO₂ reservoir under low C_s and low E. It could also be confirmed that quinoa plants balanced low soil water potential by the accumulation of compatible solutes to lower the LWP and LOP. Drought led, especially in leaves in the 1% SAP treatment, to significant reductions in CO₂/H₂O gas exchange (A_net, R_D), decreases in Y (II) and ETR in PS II, and an increase in the ETR/A ratio and over-reduced centers in PS I, pointing to an increased appearance of reactive oxygen species (ROS) in the chloroplasts. The latter change was indicated by higher levels of lipid peroxidation (MDA). It could be shown that the response of the test species Chenopodium quinoa to the addition of BC and SAP proved to be highly adaptable. The plant reacted in a very coordinated and specific way to both the danger of oversupply of SAP soil amendments under water shortage conditions and an effective adaptation to a limited water supply with 3% BC and 0.1% SAP by increasing WUE and proline content. However, BC also had a mitigating effect on the level of reactive oxygen species (ROS). It can be assumed that this effect is based on a more plant-compatible, less one-sided ion composition of BC. The results presented indicate that SAP and BC can have an impact on the water and nutrient accessibility for plants. Therefore, optimal biomass production and plant response can only be reached if plant soil interactions and competition between SAP, BC and the plant roots are taken into account when planning for climate-resilient, water-saving agriculture. Full article

Ultrafine hematite particles (<10 μm), commonly generated in beneficiation circuits, exhibit poor flocculation and slow settling, posing challenges for solid–liquid separation. This study investigates the influence of the anionic polyacrylamide (APAM) molecular weight on ultrafine hematite flocculation under controlled laboratory conditions, combining macroscopic experiments with molecular dynamics simulations (MDSs). Sedimentation tests show that the APAM molecular weight strongly affects settling kinetics, supernatant clarity, and floc structure, with the settling rate, flocculation-stage reaction time, supernatant turbidity, and underflow concentration exhibiting a non-monotonic trend and optimal performance at seven million. Under this condition, particles aggregate most efficiently, achieving a turbidity of 182 NTU, an underflow concentration of 51.5%, and the largest compact flocs, averaging 379.8 μm with a fractal dimension of 1.71. Higher molecular weights (≥9 million) induce chain coiling, reduce floc compactness, increase water retention, and impair settling. MDS indicates that polymer–surface interactions improve with an increasing polymerisation degree only up to an intermediate chain length; a polymerisation degree of 30 exhibits the most favourable extended–flexible conformation, maximal surface enrichment, strongest coordination between carboxyl groups and surface Fe atoms, lowest adsorption energy, and fastest adsorption kinetics. The functional-group distribution and hydrogen-bond analyses show that –NH₂ and –COO^– groups dominate interfacial interactions, with a polymerisation degree of 30 yielding the highest density of interfacial hydrogen bonds. By correlating macroscopic experiments with molecular-scale observations, this work provides mechanistic insight into how the APAM chain length governs ultrafine hematite flocculation, highlighting the role of polymer conformation and multipoint adsorption in controlling the settling performance. Full article

Urgent demand for wound healing treatments has driven rapid advancement in electronic skin technology. As a promising wound healing approach, electronic skin offers advantages such as flexible conformability, autonomous sensing, and intelligent regulation. However, mainstream electronic healing patches face significant challenges in complex wound applications, including insufficient coordination, delayed response, limited healing efficiency, and inadequate feedback. Therefore, developing innovative wound healing technologies that integrate high efficiency, multi-module drive, and closed-loop feedback is imperative. The advanced development of electronic skin for wound healing is urgently needed to be systematically reviewed. Here, first, the structural innovations and design strategies for biomimetic thermotherapeutic electronic skins based on thermoelectric polymer composites and interactive temperature biomimetic regulation are summarized. Subsequently, several emerging bioelectrically active electronic skins are reviewed, including drug-delivery electronic skins, multifunctional hydrogel-integrated electronic skins, and photoelectric synergistic stimulation electronic skins, along with an analysis of their advanced designs and innovative advantages. Last but not least, potential challenges facing the future development of electronic skin are explored. Practical solutions are proposed for advancing low-cost, clinically applicable, and scalable electronic skin development, aiming to drive breakthrough progress in therapeutic wound healing. Full article

The aim of this in vitro study was to evaluate and compare the color stability of different CAD/CAM ceramic materials after artificial aging induced by thermocycling. Two hundred disk-shaped specimens were fabricated from five CAD/CAM materials: high-translucent zirconia (HT), ultra-high-translucent zirconia (UHT), standard translucent zirconia (ST), a polymer-infiltrated hybrid ceramic (CERASMART 270), and a lithium disilicate glass-ceramic (GC Initial LiSi Block). Color measurements were performed at baseline and after 10,000 thermocycling cycles (5–55 °C) using a VITA Easyshade^® spectrophotometer. Color coordinates (CIE L*, a*, b*) and overall color differences (ΔE) were calculated. Statistical analysis was applied to determine material-dependent differences. All materials exhibited statistically significant color changes after thermocycling (p < 0.001). The color change varied by material. Lithium disilicate showed the highest ΔE values, whereas UHT, HT zirconia and CERASMART 270 showed lower color changes, yielding results within clinically acceptable limits. Color stability after thermocycling is highly material-dependent. Zirconia-based and polymer-infiltrated ceramics showed superior optical aging resistance compared to lithium disilicate ceramics, indicating their clinical suitability for long-term esthetic CAD/CAM restorations. Full article

Magnesium-sulfur (Mg-S) batteries present a compelling energy storage solution, characterised by their remarkable theoretical energy density and economic viability. Nonetheless, challenges arise, including swift capacity degradation and suboptimal polysulfide (acting as an electronic and ionic insulator) utilisation, mainly due to a phenomenon known as the polysulfide “shuttle effect.” This effect also leads to a decline in battery performance. The Becke, 3-parameter, Lee-Yang-Parr (B3LYP) functional and 6-311G (d,p) basis set were used to examine the optoelectronic and charge-transfer properties of a polyaniline-pyrrole (PANIPyr) composite, emphasising interatomic and electronic interactions that enhance charge transport and oxidation of MgS₂. The findings demonstrate the presence of coordination bonding between hydrogen in pyrrole and the N⁻ ion in quinonediimine of polyaniline, significantly enhancing the electrical properties of PANI. The PANIPyr_P1 (P1-pyrrole attached at position one) configuration exhibits the lowest Ɛ_gap and the highest charge-transfer capacity, compared to other studied molecules in this work, thereby improving reactivity towards polysulfides in comparison to pure PANI. Significant electrical interactions at this site establish accessible electrophilic and nucleophilic regions that stabilise the ionic sides of the polysulfides, thus reducing the shuttle effect and improving charge transport at the interface. PANIPyr_P1 demonstrates viability for minimising polysulfide migration and enhancing cathodic efficiency in Mg-S batteries, thereby laying a foundation for future investigations into polymer-based cathode modifiers. Full article

Alginate-based hydrogels, derived from brown seaweed, represent biocompatible and biodegradable materials whose properties are systematically controlled through molecular structure (M/G composition), crosslinking strategy, and compositional modification. This review synthesizes recent advances in alginate hydrogel design, encompassing fundamental structural properties, three primary crosslinking approaches—ionic coordination with divalent cations (Ca²⁺, Ba²⁺, Sr²⁺), covalent chemical linkages, and hybrid multi-crosslinking systems—and strategic modification strategies including chemical derivatization, polymer blending, and nanoparticle incorporation. These modifications address inherent limitations of native alginate, namely insufficient mechanical strength and biological inertness, thereby expanding applicability. The review examines applications across biomedical domains (drug delivery, tissue engineering, wound healing), environmental remediation, food industry systems, and emerging technologies including flexible electronics and soft robotics. Advanced fabrication techniques—3D/4D printing, microfluidics, and electrospinning—enable improved architectural control. Current evidence from preclinical and clinical studies demonstrates feasibility in specific applications, while important challenges persist, including predictable degradation kinetics, mechanical property optimization, standardization of characterization protocols, regulatory compliance, and manufacturing scalability. This review aims to provide a systematic assessment of alginate-based hydrogel development and identify areas requiring further investigation to advance clinical translation. Full article

The growing demand for marine resource development and in-depth exploration of the marine environment has positioned soft biomimetic underwater vehicles (SBUVs) as a research hotspot in the fields of underwater equipment and soft robotics. SBUVs are characterized by bodies made of flexible and extensible materials, integrating the dual advantages of softness and biomimetics. They can achieve muscle-like continuous deformation to efficiently absorb collision energy, while mimicking the propulsion mechanisms of marine organisms—such as fish and jellyfish—through undulating body movements or cavity contraction and relaxation. Such biomimetic propulsion is highly compatible with the flexible actuation of soft materials, enabling excellent environmental adaptability while maintaining favorable propulsion efficiency. Compared with traditional rigid underwater vehicles, SBUVs offer higher degrees of freedom, superior environmental adaptability, enhanced impact resistance and greater motion flexibility. This review systematically summarizes typical actuation methods for SBUVs—including fluid-powered actuation, shape memory alloy actuation, and electroactive polymer actuation—elaborating on their working principles, key technological advances, and representative application cases on SBUVs. These actuation mechanisms each offer distinct advantages. Fluid-powered systems are valued for high power density and precise motion control through direct fluidic force transmission. Shape memory alloys provide high force output and accurate positional recovery via controlled thermal phase changes. Meanwhile, electroactive polymers stand out for their rapid (often millisecond-scale) dynamic response, low hysteresis, and fine, muscle-like deformation under electrical stimuli. Current challenges are also analyzed, such as limited actuation efficiency, material durability issues, and system integration difficulties. Despite these constraints, SBUVs show broad application prospects in marine resource exploration, ecological monitoring, and underwater engineering operations. Future research should prioritize the development of novel materials, coordinated optimization of actuation and control systems, and breakthroughs in core technologies to accelerate the practical implementation and industrialization of SBUVs. Full article

Polymer modification is a well-established strategy for improving the performance and extending the service life of cementitious and other construction materials, with direct implications for environmental sustainability and infrastructure resilience. Among these polymers, polyvinylpyrrolidone (PVP), a non-ionic, water-soluble, and highly compatible polymer, has emerged as a uniquely versatile additive for mitigating degradation in aggressive environments. This review provides a critical and comprehensive synthesis of the state-of-the-art research on PVP’s roles in cement, mortar, concrete, and asphalt systems. The novelty of this work lies in its mechanistic integration and system-level interpretation, which consolidate fragmented knowledge across multiple domains—ranging from rheology and durability to nanotechnology and interfacial engineering—into a unified and coherent framework. Through cross-study comparison, this approach establishes a comprehensive understanding of PVP’s role in cementitious systems while outlining clear pathways for future research and practical implementation. This review provides the first integrated framework that connects PVP’s molecular structure, adsorption behavior, and ion-coordination mechanisms to its macroscopic influence on rheology, hydration, microstructure, and long-term durability. The review critically analyzes the underlying mechanisms, including physical pore-filling and crack-bridging, as well as chemical ion-coordination, which collectively govern PVP’s performance. Key quantitative findings are consolidated, showing that optimal PVP addition can reduce water absorption by over 35%, increase fracture toughness by ~47%, and, when used as an interfacial modifier, enhance the strain capacity of fiber-reinforced composites by over 100%. Reported benefits include improved workability, enhanced mechanical performance and toughness, superior durability under chemical and frost exposure, and the development of functional materials such as self-sensing concretes and photocatalytic coatings that support structural health monitoring and pollution mitigation. Overall, this review synthesizes current knowledge, consolidates experimental evidence in tabular form, and identifies future opportunities for leveraging PVP in the design of sustainable, low-impact, and environmentally resilient construction materials and infrastructures. Full article