Search Results (3,373)

MQ copolymers, consisting of monofunctional (M) and tetrafunctional (Q) siloxane units, are versatile materials used as additives, adhesives, and in composite materials. Functional groups, such as vinyl substituents, in M-units allow for the tailoring of properties for specific applications. This study aimed to synthesize vinyl-containing MQ copolymers (M^VinMQ) via a controlled, chlorine-free method to explore the regulation of their composition and properties. The results demonstrated precise control over the copolymer architecture, with hydroxyl content and molecular weight increasing alongside the Q-unit fraction. All obtained copolymers exhibited high thermal stability, with 5% mass loss occurring above 295 °C in air and 365 °C in argon. Fractionation data supported a molecular composite model consisting of an inorganic core and an organic shell. Polycondensation in an active medium is an effective method for the directed synthesis of structurally tunable M^VinMQ copolymers, offering a versatile platform for developing functional hybrid materials, modifiers, and cross-linking agents. Full article

Flame-retardant microcapsules were prepared using a urea–melamine–formaldehyde (UMF) shell and boric acid-crosslinked ammonium polyphosphate (APP) as the core to improve the dispersion stability and processing compatibility of phosphorus-based flame retardants. Thermal analysis showed that the microcapsules exhibited initial mass loss near 80 °C due to moisture evaporation and shell relaxation, while APP-related degradation occurred at higher temperatures, indicating delayed release of the core and enhanced thermal resistance through encapsulation. Scanning electron microscopy confirmed the formation of microcapsules, and morphological changes before and after combustion suggested the development of protective char layers. Boron-containing residues are expected to contribute to char stabilization through the formation of B–O–P structures during heating. The flame-retardant properties were evaluated using limiting oxygen index, smoke density, and vertical burning tests. Although the limiting oxygen index slightly decreased due to reduced accessible APP content, stable burning behavior was maintained, and characteristic char formation was observed after combustion. These results indicate that the UMF/APP microcapsules can improve thermal stability and handling of phosphorus-based flame retardants. The microencapsulation approach presented here may provide practical advantages for polymer processing and surface-coating applications. Full article

The threat of antimicrobial resistance (AMR) and the need for sustainable disinfectants have spurred interest in natural antimicrobials such as essential oils (EOs). However, their application is limited by volatility, poor water solubility, and cytotoxicity. Herein, we present the development of bio-based core–shell sub-micro-/nanocapsules (NCs) with encapsulated oregano (OO), thyme (TO), eucalyptus (EuO), and tea tree (TTO) oils to enhance antimicrobial (AM) performance and reduce cytotoxicity. NCs were synthesized via a nanoencapsulation method using chemically modified zein or poly(methyl vinyl ether-co-maleic anhydride) (GZA) as shell polymers, with selected EOs encapsulated in their core (encapsulation efficacy > 98%). Chemical modification of zein with vanillin (VA) and GZA with either dodecyl amine (DDA) or 3-(glycidyloxypropyl)trimethoxysilane (EPTMS) resulted in improvement in particle size distributions, polydispersity indices (PDIs) of synthesized NCs, and in the stability of the NC-dispersions in water. Antibacterial testing against Staphylococcus aureus and cytotoxicity assays showed that encapsulation significantly reduced toxicity while preserving their antibacterial activity. Among the formulations, GZA-based NCs modified with EPTMS provided the best balance between safety and efficacy. Despite this, life cycle assessment revealed that zein-based NCs were more environmentally sustainable due to lower energy use and material impact. Overall, the approach offers a promising strategy for developing sustainable, effective, and safe EO-based antibacterial agents for AM applications. Full article

The development of flexible and self-powered electronic systems requires triboelectric materials that combine high charge retention, mechanical compliance, and stable dielectric properties. Here, we report a redox reaction approach to prepare liquid metal particle-reduced graphene oxide (LMP@rGO) core–shell structures and introduce into a poly(acrylic acid) (PAA) hydrogel to create a high-performance triboelectric layer. The spontaneous interfacial reaction between gallium oxide of LMP and graphene oxide produces a conformal rGO shell while simultaneously removing the native insulating oxide layer onto the LMP surface, resulting in enhanced colloidal stability and a controllable semiconductive bandgap of 2.7 (0.01 wt%), 2.9 (0.005 wt%) and 3.2 eV (0.001 wt%). Increasing the GO content promotes more complete core–shell formation, leading to higher zeta potentials, stronger interfacial polarization, and higher electrical performance. After embedding in PAA, the LMP@rGO structures form hydrogen-bonding networks with the hydrogel nature, improving both dielectric constant and charge retention while notably preserving soft mechanical compliance. The resulting LMP@rGO/PAA hydrogels show enhanced triboelectric output, with the 2.0 wt/vol% composite generating sufficient power to illuminate more than half of 504 series-connected LEDs. All the results demonstrate the potential of LMP@rGO hydrogel composites as promising triboelectric layer materials for next-generation wearable and self-powered electronic systems. Full article

Conventional quantum mechanics treats the electron as a point-like particle endowed with intrinsic properties—mass, charge, and spin—that are inserted as axioms rather than derived from first principles. Here, we propose a thermodynamic reformulation of the electron grounded in entropy field dynamics, based on S-Theory. In this framework, the electron is composed of three distinct entropic components: S_core (a collapsed entropy core from configurational mass), S_EM (a structured electromagnetic entropy field from charge), and S_thermal (a diffuse entropy component from ambient interactions). We show that spin emerges as a rotating S_EM shell around S_core, and that electron collapse—as in quantum measurement—can be modeled as a Recursive Amplification of Sfield (RAS) process driven by entropic feedback. Through mathematical formulation and high-resolution simulations, we demonstrate how the S-field components evolve under entropic excitation, culminating in a collapse threshold defined by local entropy density matching. This model not only explains the emergence of quantum properties but also offers a thermodynamic mechanism for electron–photon interaction, wavefunction collapse, and spin generation, revealing the inner structure and dynamics of one of nature’s most fundamental particles. Full article

Double-shell ZnO/Al₂O₃ submicron hollow fibers were successfully fabricated through a combined electrospinning and atomic layer deposition (ALD) approach. Polyvinyl alcohol (PVA) fibers were first produced by electrospinning and subsequently coated with a conformal Al₂O₃ barrier layer via low-temperature ALD employing trimethylaluminum (TMA) and deionized (DI) H₂O to preserve the integrity of the temperature-sensitive polymer core. The inner polymer was then removed using two different techniques—thermal annealing and water dissolution—to compare their effects on the fiber morphology. Finally, a functional ZnO layer was deposited by thermal ALD with diethylzinc (DEZ) and DI H₂O. It was found that the polymer removal method critically determined the final structural and morphological characteristics of the fibers. Thermal annealing resulted in smooth, shrunken fibers, while water dissolution led to diameter expansion and the formation of a highly rough, bubble-like surface structure due to swelling-induced micro-cracking. The selection of the polymer removal method offers a precise and controllable route for tailoring the fiber morphology. The resulting high-aspect-ratio (HAR) structures, particularly the rough and expanded fibers, exhibit enhanced specific surface area, making them highly promising for applications in sensing, catalysis, and filtration. Full article

Rhodoliths (from Greek etymology meaning red + stone) are spheroidal accretions composed of various types of crustose coralline red algae that dwell in relatively shallow waters where sunlight allows for photosynthesis. Unlike most other kinds of algae that are attached to the seabed by a holdfast, rhodoliths are free to roll about by circumrotary movements stimulated mainly by gentle wave action and bottom currents, as well as by disruptions by associated fauna. Frequent movement exposes every part of the algal surface to an equitable amount of sunlight, which generally results in an evenly concentric pattern of growth over time. Individual structures may attain a diameter of 10 to 20 cm, representing 100 years of growth or more. Initiation typically involves encrustation by founder cells on a rock pebble or shell fragment. In life, the functional outer surface is red or pink in complexion, whereas the structure’s inner core amounts to dead weight. Chemically, rhodoliths are composed of high magnesium calcite [(Ca,Mg)CO₃], with examples known around many oceanic islands and virtually all continental shelves in the present world. The oldest fossil rhodoliths appeared during the early Cretaceous, 113 million years ago. Geologically, rhodoliths may occur in massive limestone beds composed of densely packed accumulations. Living rhodoliths commonly occur in waters as shallow as −2 to −10 m, as well as seaward in mesophotic waters up to −100 m under exceptional conditions of water clarity. Especially in shallower waters, rhodoliths are vulnerable to transfer by storm waves to supratidal settings, which result in bleaching under direct sunlight and death. Increasingly, marine biologists recognize that rhodolith beds represent a habitat that offers shelter to a community of other algae and diverse marine invertebrates. Full article

This work explores late-time gravitational collapse using timelike thin-shell methods in classical general relativity. A junction surface separates a regular de Sitter interior from a Schwarzschild or Schwarzschild–de Sitter exterior in a post-transient regime with fixed exterior mass M (ADM for ${\mathrm{\Lambda }}_{+}=0$), modelling a vacuum–energy core surrounded by an asymptotically classical spacetime. The configuration admits a natural thermodynamic interpretation based on a geometric area functional $S_{\mathrm{shell}}\propto R^2$ and Tolman redshift, both derived from classical junction conditions and used as an entropy-like coarse-grained quantity rather than a fundamental statistical entropy. Key results include (i) identification of a deceleration mechanism at the balance radius $R_{\mathrm{thr}}={(3M/{\mathrm{\Lambda }}_{-})}^{1/3}$ for linear surface equations of state $p=w\sigma$; (ii) classification of the allowable radial domain $V\left(R\right)\le 0$ for outward evolution; (iii) bounded curvature invariants throughout the shell-supported spacetime region; and (iv) a mass-scaled frequency bound $f_c{R}_S\le \xi /\left(3\sqrt{3}\pi \right)$ for persistent near-shell spectral modes. All predictions follow from standard Israel junction techniques and provide concrete observational tests. The framework offers an analytically tractable example of regular thin-shell collapse dynamics within classical general relativity, with implications for alternative compact object scenarios. Full article

Smart nanocarriers are being increasingly explored to improve the performance selectivity of cancer chemotherapy. Here, two pH-responsive magnetic nanocarriers were developed using quaternary chitosan (HTCC) functionalized with 3-(triethoxysilyl)propyl isocyanate- ICPTES (MNP-HTCC1) or 3-(glycidyloxypropyl)trimethoxysilane-GPTMS (MNP-HTCC2) to form hybrid silica shells on Fe₃O₄ cores. The resulting core–shell nanoparticles (14.5 and 12.5 nm) displayed highly positive zeta potentials (+45.4 to +27.1 mV, pH 4.2–9.5), confirming successful HTCC incorporation and strong colloidal stability. Both nanocarriers achieved high doxorubicin (DOX) loading at pH 9.5, reaching 90% efficiency and a capacity of 154 µg DOX per mg. DOX release was pH-dependent, with faster release under acidic conditions relevant to tumor and endo-lysosomal environments. At pH 4.2, MNP-HTCC1 released 90% of DOX over 72 h, while MNP-HTCC2 released 79%. Release at pH 5.0 was intermediate (67–72%), and moderate at physiological pH (43–55%). All formulations showed an initial burst followed by sustained release. Kinetic modelling (Weibull) indicated a diffusion-controlled mechanism consistent with Fickian transport through the HTCC–silica matrix. Cytotoxicity assays using MCF-7 breast cancer cells revealed greater cytotoxicity for DOX-loaded nanocarriers compared with free DOX, with MNP-HTCC1 showing the strongest effect. Overall, these HTCC-based magnetic nanocarriers offer efficient loading, controlled pH-triggered DOX release, and enhanced therapeutic performance. Full article

Widespread in coastal environments, artificial light at night (ALAN) is suspected to disrupt organisms’ biological rhythms by altering natural light cycles and thus constitutes a growing threat to these ecosystems. This study evaluates the effects of ALAN exposure at low and realistic intensity (~1 lx) on a coastal keystone species, the oyster Crassostrea gigas. The results reveal that ALAN significantly impairs the expression of core circadian clock genes (CgClock and CgBmal1) as well as the valve opening behavior, affecting rhythmic characteristics such as its robustness and daily profile. At the same time, ALAN leads to a decrease in daily shell growth and to a disruption of the gill microbiota, associated with an obliterated day/night difference in microbial alpha diversity. A direct correlation between a decrease in daily rhythm robustness, limitation of shell growth, and some microbial strands is shown, suggesting that biological rhythm disruption caused by ALAN might have harmful physiological consequences in oysters. Full article

Metal–organic framework (MOF)-based surface-enhanced Raman scattering (SERS) sensors have emerged as a versatile platform for high-sensitivity and selective detection in agricultural, environmental, and biomedical applications. By integrating plasmonic nanostructures with tunable MOF architectures, these hybrid systems combine ultrahigh signal enhancement with molecular recognition, analyte preconcentration, and controlled hotspot distribution. This review provides a comprehensive overview of the fundamental principles underpinning MOF–SERS performance, including EM and chemical enhancement mechanisms, and highlights strategies for substrate design, such as metal–MOF composites, plasmon-free frameworks, ligand functionalization, and hierarchical or core–shell architectures. We further examine their applications in environmental monitoring, pesticide and contaminant detection, pathogen identification, biomarker analysis, and theranostics, emphasizing real-sample performance, molecular selectivity, and emerging integration with portable Raman devices and AI-assisted data analysis. Despite notable advances, challenges remain in reproducibility, quantitative reliability, matrix interference, scalability, and biocompatibility. Future developments are likely to focus on rational MOF design, sustainable fabrication, intelligent spectral interpretation, and multifunctional integration to enable robust, field-deployable sensors. Overall, MOF-based SERS platforms represent a promising next-generation analytical tool poised to bridge laboratory innovation and practical, real-world applications. Full article

Nanoparticle-mediated photothermal conversion exploits the unique light-to-heat transduction properties of engineered nanomaterials to address challenges in energy, water, and healthcare. This review first examines fundamental mechanisms—localized surface plasmon resonance (LSPR) in plasmonic metals and broadband interband transitions in semiconductors—demonstrating how tailored nanoparticle compositions can achieve >96% absorption across 250–2500 nm and photothermal efficiencies exceeding 98% under one-sun illumination (1000 W·m⁻², AM 1.5G). Next, we highlight advances in solar steam generation and desalination: floating photothermal receivers on carbonized wood or hydrogels reach >95% efficiency in solar-to-vapor conversion and >2 kg·m⁻²·h⁻¹ evaporation rates; three-dimensional architectures recapture diffuse flux and ambient heat; and full-spectrum nanofluids (LaB₆, Au colloids) extend photothermal harvesting into portable, scalable designs. We then survey photothermal-enhanced thermal energy storage: metal-oxide–paraffin composites, core–shell phase-change material (PCM) nanocapsules, and MXene– polyethylene glycol—PEG—aerogels deliver >85% solar charging efficiencies, reduce supercooling, and improve thermal conductivity. In biomedicine, gold nanoshells, nanorods, and transition-metal dichalcogenide (TMDC) nanosheets enable deep-tissue photothermal therapy (PTT) with imaging guidance, achieving >94% tumor ablation in preclinical and pilot clinical studies. Multifunctional constructs combine PTT with chemotherapy, immunotherapy, or gene regulation, yielding synergistic tumor eradication and durable immune responses. Finally, we explore emerging opto-thermal nanobiosystems—light-triggered gene silencing in microalgae and poly(N-isopropylacrylamide) (PNIPAM)–gold nanoparticle (AuNP) membranes for microfluidic photothermal filtration and control—demonstrating how nanoscale heating enables remote, reversible biological and fluidic functions. We conclude by discussing challenges in scalable nanoparticle synthesis, stability, and integration, and outline future directions: multicomponent high-entropy alloys, modular photothermal–PCM devices, and opto-thermal control in synthetic biology. These interdisciplinary innovations promise sustainable solutions for global energy, water, and healthcare demands. Full article

This study addresses the issues of poor stability and difficulty in recovery of free horseradish peroxidase (HRP) by developing a multi-level composite immobilized carrier that combines high loading capacity with long-term stability. The SiO₂@MnO₂@MAF-7 core–shell structured carrier was prepared via a solvothermal self-assembly method. Three immobilization strategies—adsorption, covalent cross-linking, and encapsulation—were systematically compared for their immobilization efficacy on HRP. The material structure was analyzed using techniques such as specific surface area analysis (BET), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) to characterize the material structure. Enzyme kinetic parameter determination experiments were conducted to systematically evaluate the performance advantages of the immobilized enzyme. BET analysis showed that SiO₂@MnO₂@MAF-7 had a specific surface area of 251.99 m²/g and a mesoporous area of 12.47 nm, and its HRP loading was 50.37 U/mg (immobilization efficiency 85.03%). Compared with free HRP, the Km value of the immobilized enzyme was decreased by 42%, the activity retention rate was increased by 35–50% at 80 °C and pH 4–9, and the activity was maintained by 65% after five repeated uses. In this study, MAF-7 was combined with MnO₂/SiO₂ for HRP immobilization for the first time, and the triple effect of rigid support-catalytic synergy-confined protection synergistically improved the stability of the enzyme, providing a new strategy for the industrial application of oxidoreductases. Full article

Nano-aluminum (nAl), characterized by its high combustion enthalpy and enhanced reactivity, serves as a critical component in advanced energetic materials like solid propellants and micro-ignition devices. However, the atomic-scale mechanisms governing its core–shell structure evolution, oxidation dynamics, and interfacial interactions remain elusive to experimental probes due to spatiotemporal limitations. Molecular dynamics (MD) simulations, particularly the synergistic use of a ReaxFF reactive force field (for large-scale systems) and ab initio MD (for electronic-level accuracy), have emerged as a powerful tool to overcome this barrier. This review systematically delineates the oxidation mechanisms and core–shell structure regulation of nAl, with a focus on the multi-scale simulation paradigm integrating DFT, AIMD, and ReaxFF MD that directly supports nAl research. It critically examines the pivotal role of MD simulations in guiding the surface modification of nAl, elucidating combustion mechanisms at the atomic level, and designing interfaces in energetic composite systems. By synthesizing recent advances (2022–2025), this study establishes a clear structure–property relationship between microscopic features and macroscopic performance of nAl. Furthermore, it identifies prevailing challenges, including simulations under multi-physics loading, multi-scale bridging, and quantitative experiment-simulation validation that specifically affect nAl-based energetic systems. Finally, future research directions are prospected, encompassing the development of machine learning-empowered force fields tailored for nAl systems, multi-scale and multi-field coupling simulation frameworks targeting nAl applications, and closed-loop experiment-simulation systems for nAl-based energetic materials. This review aims to provide fundamental insights and a technical framework for the rational design and engineering application of nAl-based energetic materials in fields such as aerospace propulsion. Full article

Seawater has attracted increasing attention as a promising resource for hydrogen production via electrolysis. However, multivalent ions present in seawater can reduce the efficiency of direct seawater electrolysis (DSWE) by forming inorganic precipitates at the cathode. Bipolar membranes (BPMs) can mitigate precipitate formation by regulating local pH, thereby enhancing DSWE efficiency. Accordingly, this study focuses on the fabrication of a high-performance BPM for DSWE applications. The water-splitting performance of BPMs is strongly dependent on the properties of the catalyst at the bipolar junction. Herein, iron oxide (Fe₃O₄) nanoparticles were coated with cross-linked chitosan to improve solvent dispersibility and catalytic activity. The resulting core–shell catalyst exhibited excellent dispersibility, facilitating uniform incorporation into the BPM. Water-splitting flux measurements identified an optimal catalyst loading of approximately 3 μg cm⁻². The BPM containing Fe₃O₄–chitosan nanoparticles achieved a water-splitting flux of 26.2 μmol cm⁻² min⁻¹, which is 18.6% higher than that of a commercial BPM (BP-1E, Astom Corp., Tokyo, Japan). DSWE tests using artificial seawater as the catholyte and NaOH as the anolyte demonstrated lower cell voltage and stable catholyte acidification over 100 h compared to the commercial membrane. Full article