Macromolecular Research最新文献

Accurate evaluation of thermal conductivity in polymeric materials is crucial for the development of advanced thermal management systems in electronics. In this study, a total of five epoxy resins imine-based epoxy (IEP), azine-based epoxy (AEP), ketone-based epoxy (KEP), double imine-based epoxy (DIEP), and acetylene-based epoxy (ACEP) were synthesized. The thermal conductivity of the cured materials under various conditions was then evaluated using the transient plane source (TPS) method. Their liquid crystalline (LC) behavior was confirmed by differential scanning calorimetry (DSC) and polarized optical microscopy (POM), revealing nematic and smectic phases for azine-based epoxies (AEP) and imine-based epoxies (IEP), respectively. Determination of the optimal curing agent and curing temperature was achieved by analyzing the exothermic peaks obtained from dynamic DSC scans of various epoxy resin–curing agent combinations. The curing agent whose exothermic behavior overlapped with the LC temperature range of the epoxy resin was selected to prepare the cured materials. To ensure reliability, the thermal conductivity value was determined using the stabilized region of the residual graph from the TPS measurement, where the deviation of the temperature difference was at a minimum. When cured in the LC state, the thermal conductivity values were 0.36 W/m·K for IEP/diaminodiphenylmethane (DDM) and 0.35 W/m·K for AEP/DDM.

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Accurate thermal conductivity of LC epoxy resins was achieved by excluding unstable data regions, highlighting the importance of accurate measurement for understanding molecular ordering effects.

Hydrogels with photothermal properties were developed using polyaniline nanoparticles for potential applications in photothermal therapy and cosmetics. Polyaniline, a cost-effective, photothermal conjugated polymer, was modified with octyl side chains to enable to produce an aqueous nanoparticle dispersion by assembling with an amphiphile via a film dispersion process. In comparison to pristine polyaniline dissolved in water, polyaniline nanoparticles presented improved photostability and bathochromic shift in their absorption spectra due to conjugated backbones protected in nanoparticles, which shield the conjugated backbones from the polar aqueous environment. Alginate hydrogels were successfully fabricated by mixing the water dispersed conjugated polymer nanoparticles with a sodium alginate solution, followed by calcium ion crosslinking. Compared with sodium alginate hydrogels without nanoparticles, the obtained hydrogels showed significantly improved mechanical and photothermal properties due to the contributions of polyaniline nanoparticles as both a nanofiller and a photothermal agent. The enhanced stability and sustained photothermal performance are critical features for applications requiring prolonged activity under oxidative stress, such as photothermal-mediated therapies.

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Alginate hydrogels composited with polyaniline nanoparticles presented photothermal properties with enhanced mechanical properties.

This study explores the asymmetric bouncing dynamics of a binary drop with viscosity contrast on the inner surfaces of cylinders decorated with a circumferential ridge. The drop consists of a low-viscosity water phase and a high-viscosity glycerin–water mixture, forming an internal interface oriented perpendicular to the ridge. Using Volume of Fluid simulations, this study analyzes the effects of surface curvature, viscosity ratio, and Weber number on retraction behavior and separation of the low-viscosity component. Two distinct retraction modes are identified: bi-directional retraction, in which the film retracts symmetrically in both axial and azimuthal directions, and uni-directional retraction, dominated by axial collapse. A regime map reveals that separation occurs above a critical threshold, accompanied by a transition from bi-directional to uni-directional retraction. The dimensionless residence time of the low-viscosity phase follows distinct scaling laws for each retraction mode. Theoretical predictions based on retraction dynamics are consistent with simulation results and provide a clear interpretation of the underlying mechanisms. These findings demonstrate that both geometric confinement and viscosity contrast play critical roles in dictating asymmetric momentum redistribution and drop separation, offering a framework for the design of hybrid-fluid systems for selective liquid handling.

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This study highlights the importance of curvature in determining the retraction pathway: while higher curvature promotes symmetriccollapse and reattachment, lower curvature favors uni-directional retraction and efficient drop breakup.

The effect of fiber shape on UO₂²⁺ adsorption performance was investigated using three polyacrylonitrile (PAN)-based fibrous adsorbents: commercial spun yarn (PAN-Y), nonwoven (PAN-NW), and electrospun nanofiber (PAN-NF). All fibers were functionalized via amidoximation, converting nitrile groups into amidoxime ligands. The PAN-NF exhibited nearly complete conversion (99.8%) of nitrile groups, compared with 96.5% and 89.5% for PAN-Y and PAN-NW, respectively. Structural analyses revealed that the nanofiber morphology was preserved after functionalization. Adsorption isotherm studies showed that nanofibrous adsorbent achieved a maximum UO₂²⁺ adsorption capacity of 99.9 mg/g, significantly higher than adsorbents derived from PAN-Y and PAN-NW (≈30 mg/g). The adsorption of nanofibrous adsorbent followed the Langmuir model, suggesting monolayer chemisorption onto homogeneous amidoxime binding sites, whereas yarn- and nonwoven-shaped adsorbents were better described by the Freundlich model, reflecting heterogeneous adsorption behavior. Kinetic analyses confirmed pseudo-second-order fitting for all samples, indicating chemisorption as the dominant mechanism. A 60 day field test in Caspian Sea seawater demonstrated that PAN-NF adsorbent achieved over 800-fold higher UO₂²⁺ adsorption compared with commercial fibers, along with enhanced selectivity over VO²⁺.

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With the advancement of modern industry and rising living standards, environmental pollution has become an increasingly serious and widespread concern. In response, hydrogels have emerged as promising multifunctional materials to mitigate pollution due to their high porosity, tunable structure, hydrophilicity, and capacity to incorporate diverse functional groups, which enable both effective adsorption of pollutants and real-time detection through electrochemical sensing. Furthermore, their responsiveness to external stimuli, coupled with notable mechanical robustness and intrinsic self-healing behavior, positions them as versatile candidates for diverse environmental applications. This review outlines recent progress and key innovations in hydrogel-based materials for heavy metal adsorption while also addressing their integration into electrochemical detection systems. In addition, it briefly discusses hydrogel-based electrochemical sensors for detecting emerging contaminants, such as pesticides, dyes, and microplastics. Moreover, the emerging role of machine learning in guiding the rational design, intelligent development, and performance optimization of hydrogel-based systems is highlighted. The review concludes by discussing current limitations and outlining future research directions for their sustainable implementation in real-world technologies.

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Hydrogels for monitoring and remediation of heavy metals

Facial masks have emerged as a dominant category within the skincare market; however, conventional materials such as non-woven fabrics (composed of cotton or regenerated cellulose fibers), hydrogels, and bio-cellulose often present limitations in terms of skin adhesion, production complexity, cost, or potential skin irritation. To overcome these challenges, polyvinyl alcohol (PVA) has attracted attention due to its water solubility, biocompatibility, biodegradability, and excellent mechanical strength, making it a promising candidate for next-generation facial mask materials. In this study, we developed an electrospun nanoweb-based facial mask composed of a PVA/functional ingredient (FI) composite, leveraging the advantages of electrospinning to produce nanofiber structures characterized by high porosity, large surface area, and intrinsic softness. These features contribute to enhanced skin adhesion and efficient FI loading. We systematically investigated the effects of electrospinning parameters and FI content on fiber morphology and physicochemical properties. Furthermore, the skincare efficacy of the developed facial mask was quantitatively evaluated by measuring changes in moisture content, pore size, wrinkle, pigmentation, and skin tone before and after application. The results demonstrated improvements in overall skin parameters, highlighting the potential of PVA-based nanowebs as effective, biocompatible, and environmentally sustainable alternatives to conventional sheet masks. This study offers valuable insights into the development of next-generation home-use skincare products that combine functionality, user comfort, and ecological responsibility.

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π-Conjugated polymers have attracted significant attention due to their tunable optoelectronic properties and potential applications in organic electronics. In this study, we report the synthesis and characterization of novel π-conjugated polyphenylenes (PPs) with poly(o-phenylenediamine) (POPD) graft chains. The graft copolymers were synthesized via oxidative polymerization of o-phenylenediamine (OPD) in the presence of PPs containing 2,3-diamino-1,4-phenylene units. Structural characterization by IR and ¹H NMR spectroscopy confirmed the successful incorporation of POPD side chains onto the PP backbone. The optical properties of the graft copolymers were studied by UV–Vis and photoluminescence spectroscopy, revealing features consistent with an extended π-conjugated system. Electrochemical properties were evaluated via cyclic voltammetry, revealing enhanced redox activity due to the extended π-conjugated system. The incorporation of POPD chains led to increased oxidation and reduction potentials, highlighting their potential for electroactive applications.

Graphic abstract

Novel π-conjugated polyphenylenes (PPs) with poly(o-phenylenediamine) (POPD) graft chains were synthesized via the oxidative polymerization of o-phenylenediamine in the presence of PPs containing 2,3-diamino-1,4-phenylene units. The graft copolymerization enhanced the photoluminescence and electrical conductivity of the PPs. The materials underwent electrochemical oxidation of the polymer backbone and electrochemical reduction of the graft chains.

High-boiling solvents are essential for inkjet-printed phosphorescent organic light emitting diodes (PHOLED), but their low vapor pressure leaves residual molecules that form dipolar sites, inducing polaron formation and quenching triplet emission. To overcome this, we introduced a vacuum-assisted annealing (VAA) strategy that removes > 80% of ethyl p-toluate and > 75% of 3-ethylbiphenyl from Ir(mppy)₃-doped green PHOLED films. Efficient solvent removal was confirmed by mass spectroscopy, and photoluminescence decay indicated an extended triplet lifetime. Moreover, nanoscale surface analysis and absorption spectroscopy verified that VAA preserves film uniformity, smoothness, and the electronic structure of the Ir(III) complex. As a result, VAA-treated PHOLEDs achieved an external quantum efficiency (EQE) of 6.4%, a 75% improvement over spin-coated references. Under fully ambient inkjet-printing, devices also reached 4.4% EQE, representing a 30% gain compared to untreated films. This study demonstrates that residual solvent removal is the key bottleneck in printed PHOLEDs and establishes VAA as a simple, polymer-compatible strategy to enhance device performance under ambient, large-area processing conditions.

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Vacuum-assisted annealing (VAA) effectively eliminates residual of high-boiling-point ethyl p-toluate and 3-ethylbiphenyl solvent from the phosphorescent EML processed under ambient conditions. This process removes dipolar solvent pockets, thereby preserving the emission characteristics and enhancing film uniformity. This increases the external quantum efficiency of VAA-based devices by 75% (from 3.7 to 6.4%), identifying residual solvent as the primary constraint for enabling an ambient and scalable fabrication process.

This study investigates the synthesis and optimization of hierarchical lithium iron phosphate (LiFePO₄) cathode materials using a microwave-assisted hydrothermal method, aiming to enhance electrochemical performance while maintaining economic feasibility. We systematically examined the effects of polyvinylpyrrolidone (PVP) concentration, precursor molar ratios, and various carbon sources for in-situ carbon coating. An optimal PVP concentration was found as 25 wt% to promote well-defined hierarchical micro/nano structures. Citric acid served as both a chelating agent and carbon source, significantly influencing particle assembly and performance. A dual-carbon-source approach (citric acid + sucrose) improved morphology and electrochemical characteristics, with an optimal sucrose content of 15 wt%. Techno-economic analysis based on the cost-to-capacity ratio (CCR) revealed that the most cost-effective and high-performing condition was Li:Fe:P = 3:1:2 with a citric acid content 1.2 times the Fe molar ratio (CA1.2), achieving initial capacities of ~ 150 mAh g⁻¹ at 0.1C and ~ 100 mAh g⁻¹ at 1C. Additional carbon source such as glucose showed performance improvements but no linear benefits with increasing content, indicating the presence of optimal levels. These findings provide practical guidelines for developing commercially viable LiFePO₄ cathodes by balancing electrochemical efficiency and material cost.

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Microwave-assisted hydrothermal synthesis of hierarchical LiFePO₄ cathodes optimized by carbon sources for enhanced electrochemical performance and economic viability.

Injured tissues often require immediate closure to restore the normal functionality of the organ. However, most hydrogels used in wound healing have poor adhesion to the tissue and weak elastic properties, limiting their ability to provide effective wound protection. Additionally, hydrogels with self-healing capacity can automatically repair themselves after mechanical damage, extending their lifespan and providing better wound protection, especially in critical situations. This study explores the influence of oxidized pullulan concentration on the bioadhesive, and physicochemical properties of chitosan and pullulan (CS/APUL) hydrogels. The adhesive strength, rheological test, thermal analysis, morphology, chemical nature, and swelling studies of the hydrogels were investigated. The findings demonstrated that the CS/APUL hydrogels rapidly formed self-healing scaffolds and exhibited improved elastic strength and tunable adhesion ranging from 16 ± 1.0 to 30.3 ± 2.52 kPa. The adhesive properties of the gels were attributed to the presence of aldehydes and amino groups. In addition, the CS/APUL hydrogels strength increased from 661.2 ± 228.5 to 1482 ± 504.0 Pa. Therefore, the CS/APUL hydrogels can be used for various applications, such as wound dressings and adhesives.

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Synthesis of tissue adhesive, self-healing and injectable chitosan/pullulan hydrogels via Schiff base reaction