Macromolecular Research最新文献

Hyperbranched thiol (Hyperbranched mercaptopropionate, HBMP) was synthesized using a commercially available hydroxyl-terminal hyperbranched oligomer and 3-mercaptopropionic acid applying a low-temperature esterification reaction. The chemical structure and molecular weight analysis of synthesized HBMP were investigated by Fourier transform infrared spectroscopy (FT-IR) and gel permeation chromatography (GPC). The synthesized HBMP was analyzed with curing kinetics, thermal/mechanical properties, and adhesion trait with bisphenol-A-type epoxy resin compared to pentaerythritol tetra-mercaptopropionate (PETMP). The curing kinetics between HBMP and epoxy resin required higher activation energy compared to PETMP case. In addition, it was confirmed that as the content of HBMP increases, the thermal and mechanical properties decrease, but the adhesion property was greatly improved. These results indicate that incorporating hyperbranched thiol in epoxy resin is an efficient method to utilize the material as an adhesive layer.

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Synthesis procedure of HBMP reaction with BoltornTM P1000 and 3-MPA.

Conjugated polymers derived from polyfluorene and featuring sulfonate groups in their side chains were synthesized for interlayer in both fullerene and non-fullerene organic solar cells (OSCs). These polymers, specifically denoted as PFS-T-x (x = H, Li), establish an advantageous interfacial dipole through the ionic functionality located at the side chains. Remarkably, the key parameters of organic solar cells, such as ({J}_{sc}) and (FF,) exhibit improvements as the size of the cation increases. The highest power conversion efficiency (PCE) was achieved using PFS-T-Li as interlayer, reaching up to 9.11% and 16.3% for the device based on fullerene and non-fullerene, respectively. This study can provide a deeper understanding and potential enhancements in the performance of OSCs utilizing polymers as universal interlayers.

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This study explored the impact of different countercations in conjugated polymers used as an interlayer in organic solar cells. It was discovered that the conjugated polyelectrolyte containing lithium countercations produced the highest power conversion efficiency, ascribed to the creation of an advantageous interfacial dipole.

This study presents the synthesis of silica-embedded carbon nanofibers (SiO₂/eCNFs) as additives to enhance the heat dissipation properties of epoxy molding compounds (EMCs) for semiconductor packaging. Three different sized SiO₂ nanoparticles were prepared and added to the precursor solution for polyacrylonitrile (PAN) nanofibers. Through electrospinning and carbonization, SiO₂ nanoparticles-embedded PAN nanofibers were successfully converted to SiO₂/eCNFs. As-fabricated SiO₂/eCNFs were mixed with EMC in different concentrations from 0.1 to 1.0 wt% to investigate the effect of SiO₂/eCNFs on EMC in perspective of thermal and mechanical properties. Under our experimental conditions, the addition of 500SiO₂/eCNFs with 0.4 wt% EMC achieved a 67% enhancement in thermal conductivity and a 43% higher impact strength compared to pristine EMC. The improved thermal and mechanical properties by adding SiO₂/eCNFs additives can be attributed to two factors: one-dimensional carbon and embedded SiO₂ nanoparticles. The presence of one-dimensional carbon successfully enhanced the thermal conductivity owing to its natural graphitic characteristics and dimensional advantages. In addition, the optimal size of the SiO₂ nanoparticles provided more heat dissipation routes while maintaining the packing factor compatibility with the SiO₂ fillers in the EMC. In practical EMC applications for semiconductor chips, infrared (IR) camera observations confirmed a faster increase in the surface temperature with the use of SiO₂/eCNFs-EMC, demonstrating the potential of these new EMC additives as next-generation high-performance semiconductors.

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The improvement in the thermal conductivity of the chip molded in epoxy molding compound (EMC) through the addition of SiO₂-embedded carbon nanofibers (SiO₂/eCNFs) is demonstrated. The SiO₂/eCNFs-EMC molded chips exhibited enhanced thermal conductivity, attributed to the formation of heat pathways through the combination of SiO₂ and CNFs.

This study reports the development of a novel biomass-based epoxy vitrimer using bio-derived monomers and a fully bio-based cross-linking agent. Specifically, di-epoxy, tri-epoxy, and soybean oil (SO)-epoxy monomers were synthesized from renewable sources of 2,5-furandicarboxylic acid (FDCA), protocatechuic acid (PCA), and soybean oil, respectively. A fully bio-based tetra-functional thiol cross-linker was also synthesized from α-lipoic acid. The resulting epoxy resins exhibited high biomass contents (77.10% for di-epoxy, 74.30% for tri-epoxy, and 74.00% for SO-epoxy) demonstrating their sustainability. These resins, which can be cured at relatively low temperatures, exhibited exceptional mechanical properties with tensile strengths of up to 55.76 MPa. Moreover, the resins exhibited stress–relaxation behavior and reprocessing capabilities through the integration of thiol–epoxy reactions and transesterification, marking a significant advancement in the development of sustainable alternatives to conventional petroleum-based thermosets. This study underscores the potential application of these bio-based, reprocessable epoxy vitrimers to the reduction of environmental pollution and greenhouse gas emissions.

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The growing demand for efficient energy storage solutions has driven significant advancements in supercapacitor technology, aimed at overcoming the traditional limitations of low energy density. This article reviews strategies for enhancing the energy density of supercapacitors, focusing on advancements in electrolyte formulations, activated carbon materials, pseudocapacitive materials, and binder technologies. Aqueous, ionic liquid, and organic electrolytes have been optimized to expand voltage windows and improve ionic conductivity, thereby increasing energy storage capacity. The development of high specific surface area carbon materials and the precise tailoring of pore size distributions have been shown to enhance capacitance. Pseudocapacitive materials, including metal oxides and MXenes, have demonstrated the potential for significantly higher energy densities through redox-active mechanisms. Innovations in binder systems, particularly those employing conductive materials like reduced graphene oxide, have further improved electrode performance by enhancing structural integrity and ion transport. A key focus is the role of polymer binders, which are vital for reducing the internal resistance and subsequent heat generation. Research in this area aims to develop binders that minimize resistive losses, improve ion transport efficiency, reduce heat generation and maintain optimal operating temperatures, prevent thermal degradation, and increase energy density. Continuous research into new materials and formulations for polymer binders is essential for advancing supercapacitor technology.

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In this work, novel nanoparticles based on stearyl polyoxyethylene ether (Brij S100) and heparin for oral delivery of cisplatin were developed. The Brij S100 was covalently grafted with heparin (Hep) via the help of cystamine as a linker molecule and the successful conjugation of Hep and Brij S100 was proved by FT-IR and ¹H-NMR spectroscopy techniques. The Hep-Brij S100 copolymer was self-assembled to form the micelle structure at the minimum concentration (CMC value) of 392 ± 23 µg/ml. Cisplatin (Cis) was loaded into the Hep-Brij S100 nanogels with high drug loading content (4.88%) and efficiency (93.60%). The results of DLS and SEM revealed the nanoscale of particles (170.5 nm) with homogeneity of dispersed colloidal nanoparticles. The in vitro release of Cis from Hep-Brij S100 nanogel followed the Fickian diffusion. Furthermore, the pH-responsive release profile of Cis showed that Hep-Brij S100 nanoformulation was suitable for oral administration, without inducing any cytotoxic effect on normal cells, even at the high concentration (100 mg/ml). Importantly, the Hep-Brij S100/Cis nanomedicine exerted better cytotoxicity (IC₅₀ = 3.26 ± 0.19 µg/mL) than that of the free Cis (52.81 ± 6.26 µg/mL) on MCF7-breast cancer cells. These results strongly indicated that Hep-Brij S100 nanogels possess great potential for the oral delivery of chemotherapies.

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A new approach for the selective detection of glucose was studied by a biomimetic method using pH-sensitive polymer. For this, the pH-sensitive polymer of polymethacrylic acid (PMAA) and the glucose-selective oxidizing enzyme of glucose oxidase (GOD) were incorporated to the pore-selectively –COOH functionalized film by amide covalent bond. The –COOH functionalized porous film was fabricated by casting of polyimide (PI) solution under humid conditions containing KOH. The GOD selectively oxidizes glucose to produce gluconic acid which acts as an H⁺ source able to stimulate the pH-sensitive polymer. The morphology of pore surface was changed to a rough state by adding glucose due to the coil-to-globule transition of pH-sensitive polymer. The degree of roughness was indicated by the aggregated particle size distribution. This smart film can have potential applications in the field of biosensors for direct H⁺ detection or H⁺ producing materials by enzymatic reactions as a biomimetic system.

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A biomimetic system for selective glucose detection was developed using a pH-sensitive polymer. A porous film functionalized with –COOH was fabricated, and glucose oxidase (GOD) was covalently bonded with polymethacrylic acid (PMAA). GOD oxidizes glucose to produce gluconic acid, triggering the coil-to-globule transition in PMAA, resulting in surface roughness. This system shows potential for biosensors detecting H⁺ through enzymatic reactions.

The antimicrobial performance of polyurethane (PU) fiber was significantly enhanced by integrating nanoparticles fabricated from polymers based on a zwitterion in polyacrylic acid grafted oleyl amine (PAA-g-OA). The PU fiber was fabricated by blending PU with colloidal nanoparticles, PAA-g-OA/zwitterion. Our findings showed a notable enhancement in antimicrobial properties of PU fibers bearing polymer NPs, increasing to 99.9% with the grafting of the zwitterion into PAA-g-OA even after a laundering process with a detergent. This improvement is primarily attributed to the bacteriostatic effect of the zwitterion, which enhances electrostatic attraction and hydration, because of the substantial difference in removing gram-positive bacteria (S. aureus) compared to gram-negative bacteria (E. coli).

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Antibacterial polyurethane fibers bearing nanoparticles with surface zwitterions

In this study, we investigated the effect of fucoidan concentration and salts (NaCl, KCl, and CaCl₂) on the rheological properties of carboxymethyl cellulose (CMC)–fucoidan mixtures. All mixtures exhibited shear-thinning behavior, with the apparent viscosity (η_a) of CMC–fucoidan mixtures at shear rates < 3.0 s⁻¹ being higher than that of CMC alone. However, as the shear rate increased to ≤ 30 s⁻¹, a more significant decrease in η_a was observed in CMC–fucoidan mixtures than in CMC alone. Consequently, the η_a,100 value of the mixtures decreased in a fucoidan concentration-dependent manner. In contrast, viscoelastic moduli increased with a higher fucoidan concentration, with a more pronounced increase observed in the elastic modulus than in the viscous modulus. Upon the addition of monovalent salts, the η_a value of CMC–fucoidan mixtures decreased due to the charge screening effect of cations. Conversely, the opposite result was observed with CaCl₂ addition due to Ca²⁺-induced crosslinking between both anionic polymers. Moreover, regardless of the salt type, CMC–fucoidan mixtures with salt showed higher viscoelastic moduli than those without salt, with a noticeable increase observed when CaCl₂ was added. This was likely due to the indirect/direct crosslinking effect of mono- and divalent cations. Our findings demonstrate that fucoidan and CMC exhibit a viscoelastic synergistic interaction, which is sensitive to shearing and influenced by the type of salt.

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The effect of fucoidan concentration and salt addition on the rheological properties of carboxymethyl cellulose–fucoidan mixtures was investigated. Rheological synergism between the two anionic polymers occurred due to the formation of an entangled network with hydrophobic junction zones. The addition of salt enhanced this synergism through the indirect/direct crosslinking effects of mono- and di-valent cations.