ACS Applied Polymer Materials最新文献

This study examines the influence of carbon additives on the performance of rubber binder-based anodes in lithium-ion batteries, with a particular focus on a binder consisting of 49% poly(methyl methacrylate)-grafted natural rubber (MG49). This research is a continuation of previous efforts to better understand how different commercial carbon additives, varying in particle size and shape, affect binder cohesion and overall anode performance. A series of physicochemical and electrochemical techniques, including X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), cyclic voltammetry (CV), and dynamic electrochemical impedance spectroscopy (DEIS), were employed to assess the effects of these additives on binder cohesion and overall anode performance. Electrodes incorporating Super P exhibited a high initial specific discharge capacity of 299.8 mAh/g (G6-15), with 98.6% initial Coulombic efficiency and 77.8% capacity retention after 50 cycles. C65-based electrodes demonstrated excellent performance, with a specific discharge capacity of 342.3 mAh/g (C6-15) and the highest capacity retention of 89.5%. In contrast, KS6L-based electrodes suffered from poor electrochemical performance, showing an initial capacity of only 1.237 mAh/g (K6-8), high charge transfer resistance (R_ct of 218.5 Ω), and a drastic loss in capacity over cycling. Lithium-ion diffusion coefficients revealed superior kinetics for Super P and C65, with values of 1.087 × 10^–8 cm²/s (G6-15) and 1.645 × 10^–8 cm²/s (C6-10) in the oxidation process, while KS6L exhibited limited ion mobility (2.316 × 10^–12 cm²/s for K6-10). These findings underscore the critical role of carbon additive selection in enhancing the energy density, stability, and lifespan of lithium-ion batteries. The study provides valuable insights into optimizing binder–additive interactions to improve electrode performance in next-generation energy storage applications.

Transdermal drug delivery (TDD) is emerging as a favorable alternative to traditional oral and injectable drug administration routes, offering a noninvasive, pain-free option with controlled and sustainable drug delivery. However, developing a TDD patch that delivers drugs with a high efficiency while being skin-friendly is still challenging. Here, we report an ultrathin and breathable iontophoretic patch for TDD application. The ultrathin dye-loaded electronic tattoo (UDET) consists of silk nanofibers (SNFs) and graphene. Cationic rhodamine B (RB) and methylene blue (MB) model drugs are incorporated in SNFs. The UDETs can be seamlessly affixed to nonuniform and pliable pigskin. The performance of the iontophoretic system can be fine-tuned by adjusting the applied voltage and duration of the iontophoresis process. The UDET delivers the RB and MB model drugs into pigskin up to a depth of >800 μm under a bias voltage of 20 V within 2 h. Additionally, to evaluate the potential for real-world applications, the diffusion of Dextran molecules of varying molecular weights was examined. The penetration depth of low molecular weight Dextran (Dex-10,000) was significantly higher than that of high molecular weight Dextran (Dex-70,000), demonstrating the influence of molecular size on diffusion efficiency. Our results show the UDET patch’s controllable and efficient delivery capability as well as underscore the potential of UDETs in augmenting TDD through controlled electric fields. This feature would be pivotal for the delivery of therapeutics in scenarios where conventional methods may be inadequate.

Membrane separation technology has garnered significant attention for CO₂ separation and purification, with mixed matrix membranes (MMMs) emerging as promising candidates due to their advantages of ease of processing, high mechanical strength, and thermal stability. The development of effective fillers for separation performance becomes one of the key foci in this area. In this work, CC3, a type of porous organic cages (POCs), was synthesized and functionalized with two amino-containing materials of different chain lengths. Polyethylenimine (PEI) and diethylenetriamine were used as modification agents to successfully graft amino groups onto the CC3 crystals to form defect-free Pebax mixed matrix membranes containing amino-functionalized CC3. The special porous structure of CC3 increases the gas permeability of the mixed matrix membrane by providing extra channels for the transportation of CO₂. Besides, amino groups on functionalized CC3 interact with the chains of Pebax through hydrogen bonding, thus improving the compatibility between filler and matrix. The amino groups can further facilitate the transport of gases across the membrane through reversible reactions with CO₂, which is further enhanced under humid conditions. Under optimal conditions, at 1 bar and 30 °C, the CO₂ permeability of Pebax/PEI@CC3-MMMs was 342.33 Barrer with a selectivity of 33.38, while Pebax/DETA@CC3-MMMs exhibited a CO₂ permeability of 273.34 Barrer and a selectivity of 35.77. This work demonstrates that amino-functionalized POCs (CC3) can effectively enhance the CO₂ permeability and the CO₂/N₂ selectivity, which may provide a way to develop high-performance mixed matrix membranes with superior separation properties.

Carbazole-based conjugated polymers are revolutionizing electrochromic technology and becoming indispensable materials for cutting-edge applications. These polymers showcase exceptional electrochromic capabilities, featuring high coloration efficiency, fast switching times, and outstanding stability, all tailored to their unique structure and doping levels. This review explores the innovative realm of EC conjugated polymers, highlighting the charge transport and photoconductive role of carbazole (Cz) as a main chain building block or subunit, making these materials ideal for use in smart windows, displays, and other optoelectronic devices. The resulting polymers of Cz demonstrate diverse electrochromic behaviors, ranging from transparent to green and blue color transitions, depending on the specific structure and doping level. The presence of carbazole units within the polymer backbone or as side chain substituents allows for further tuning of the material’s properties through chemical modification. Furthermore, our review emphasizes the importance of understanding the relationship between the molecular structures of the polymers and their resulting electrochromic properties. By systematically studying the effects of different substituents, linkage positions, and polymerization techniques, researchers can gain valuable insights into the design principles that govern the performance of these materials. This knowledge is crucial for the development of next-generation electrochromic devices with improved efficiency, durability, and functionality.

Covalent organic frameworks (COFs) featuring periodic skeletons and extended π-conjugated structures have emerged as a promising class of photocatalytic materials. However, inadequate charge separation and fast photogenerated carriers’ recombination in COFs severely limits their photocatalytic activities. Herein, a defect TADH–COF-COOH with carboxylic acid groups introduced in situ was synthesized by selecting 4,4′,4’’-(1,3,5-triazine-2,4,6-triyl) triphenylamine as the amino building block and 4′-formyl-[1,1′-biphenyl]-4-carboxylic acid as the aldehyde component. Compared to the intrinsic COF (TADH–COF) and the single-defect COF (TADH–COF-H), TADH–COF-COOH significantly enhances the local built-in electric field due to the presence of carboxyl groups, thereby improving the separation of the photogenerated charges and effectively mitigating the nonradiative recombination issue commonly observed in COFs used as photocatalysts. Benefiting from the introduction of highly polar carboxyl groups and defect engineering design on the COFs skeleton, TADH–COF-COOH exhibits superior performance in the photocatalytic removal of uranium from actual nuclear wastewater. These findings highlight the great potential of using simple defect engineering strategy to induce enhanced built-in electric field in customizing porous materials to improve photocatalytic efficiency.

In spite of the remarkable success in the preparation of comb-like polymers, their practical applications are yet to be fully exploited. Herein, partially renewable comb-like polymers were efficiently synthesized via grafting-through strategy, and the potential applications of these materials as phase change materials and hot-melt adhesives were preliminarily explored. At first, ring-opening metathesis polymerization (ROMP) of various tricyclic oxanorbornene derivatives readily furnished comb-like polymers P1–P6 featuring rigid backbone and flexible yet crystalline side chains. An enhancement in crystallinity is observed while prolonging the chain length of the pendant alkyl groups of these specimens. The ordered arrangement of aliphatic side chains derived from the van der Waals interaction is verified by wide-angle X-ray diffraction (WAXD) patterns of these polymers. Furthermore, P1–P6 films show mechanical robustness and reprocessability, and their strength and toughness are discovered to be individually governed by the rigidity of the polymer backbone and the stiffness of pendant groups, respectively. As for thermal energy storage/release properties, the P6 film exclusively displays a unique insulation property and excellent thermal durability such as shape stability, structural integrity, and highly reliable heat storage capability during a 500 times thermal cycling test. Meanwhile, the adhesion property of these comb-like polymers is estimated to be appreciably influenced by the molar fraction of the molten state. Thus, polymer P3, the specimen possessing the utmost chain length of amorphous side chains, exhibits optimal adhesive performance with anticorrosiveness and reusable characteristics.

Polyureas (PUas) are a versatile class of polymers with wide applications in coatings, flexible electronics, 3D printing, and engineering protection. Herein, a series of thermoplastic PUas with diverse properties were prepared from diisocyanates with different structures and a carbon-dioxide-based oligourea (OUa). First, OUa was synthesized from diamines and carbon dioxide (CO₂); then a group of thermoplastic PUas were fabricated by reacting OUa with diisocyanates. The formation of CO₂-based OUa and its subsequent polymerization with diisocyanates are necessary steps in producing high-performance PUas. The properties of the synthesized PUas depend on the diisocyanate structure. While 4,4′-diphenylmethane diisocyanate (MDI) and CO₂-based OUa produced a tough material with excellent mechanical properties including a tensile strength of 62 MPa, Young’s modulus of 1104 MPa, elongation at break of 209%, and toughness of 85 MJ·m^–3, 1,6-hexamethylene diisocyanate (HDI) and CO₂-based OUa produced an elastic material with a tensile strength of 50.5 MPa, Young’s modulus of 382 MPa, elongation at break of 456%, and toughness of 129 MJ·m^–3. Moreover, PUa derived from HDI and OUa also presented excellent damping properties with an energy absorption efficiency of 94% and an energy dissipation density of 23.0 MJ·m^–3. It could be used as a damping and protective material for wheels, buildings, driveways, etc. It is worth noting that the PUas also exhibited good reprocessing properties, maintaining their mechanical properties after two cycles of reprocessing. Additionally, all the PUas showed good thermal stability, with initial degradation temperature values ranging from 287 to 313 °C.

Maintaining ultrahigh heat resistance, a low thermal expansion coefficient (CTE), and adequate colorless transparency concurrently poses a significant challenge for colorless polyimides (CPIs), especially as substrate materials for flexible optoelectronic devices. In this work, we designed and synthesized a hydrogen-bonding carbazole tetraphenyl aromatic diamine, 2,7-bis[2-trifluoromethyl-4-aminophenyl]-9H-carbazole (2,7-CPFDA). The corresponding polyimide (PI) films were synthesized via the copolymerization of 2,7-CPFDA and 2,2′-bis(trifluoromethyl)benzidine (TFDB) with 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA) at varying molar ratios. All copolymer PI films presented high heat resistance with the 5% weight loss temperatures (T_d5) between 552 and 563 °C, and the glass transition temperatures (T_g) ranged from 354 to 380 °C. As the content of 2,7-CPFDA increased, the CTE decreased from 17.6 to 10.4 ppm K^–1, while the tensile modulus (E) rose from 5.7 to 6.7 GPa, and the elongation at break (ε) improved from 5.4% to 28%. When BPDA was substituted with 9,10-diphenyl-9,10-bis(trifluoromethyl)-9,10-dihydroanthracene-2,3,6,7-tetraacid dianhydride (6FDPDA) and 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), the CPI films exhibited overall favorable properties. Notably, C–PI-7 exhibited a high T_g of 456 °C, excellent mechanical properties (E = 6.7 GPa, ε = 11.9%), low CTE (8.7 ppm K^–1), and high transmittance at 450 nm (T₄₅₀ = 86.1%), thereby meeting the performance requirements for flexible electronic devices.

Polyurethane, as a highly adaptable polymeric precursor, plays a pivotal role in a wide range of advanced applications, particularly in biomedical engineering, regenerative medicine, and multifunctional material design. The Baylis–Hillman reaction synthesized a multifunctional chain extender that provided a suitable platform for postmodification of the polyurethane. Therefore, this study aims to engineer unsaturated hard domains tailored for postsynthetic modifications by designing and synthesizing a novel chain extender through the Baylis–Hillman reaction. The postpolymerization of unsaturated hard domains was accomplished via thiol–ene chemistry as a clickable reaction. This was accomplished by modifying gelatin with γ-thiobutyrolactone, which subsequently served as one of the reactants in the thiol–ene reaction. The influence of the hard segment content on the thiol–ene reaction was systematically investigated to optimize the fabrication of cross-linked gelatinized polyurethane films, highlighting its critical role in controlling the network architecture and mechanical properties. Interestingly, the results demonstrated that the hard segment content plays a pivotal role in governing the formation and extent of cross-linking in the synthesized polyurethane networks. Attenuated total reflection infrared spectroscopy (ATR-FTIR) and nuclear magnetic resonance (NMR) confirmed the successful synthesis of an unsaturated-chain extender and incorporation into the polyurethane backbone. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and atomic force microscopy (AFM) were employed to investigate the effect of hard segment content on the formation of cross-linked gelatinized-polyurethane films. Mechanical analysis revealed a direct correlation between the hard segment content and the cross-link density of the synthesized samples. Furthermore, X-ray photoelectron spectroscopy (XPS) confirmed surface composition variations in the polyurethane films upon the incorporation of thiolated gelatin.

Polyurethane (PU) has developed rapidly, and it has become an irreplaceable polymer material. Nonisocyanate PUs (NIPUs) have become the focus of research due to the green synthesis route that does not use toxic isocyanates. However, NIPUs face great challenges such as poor mechanical properties, heat resistance, and lack of functions, which greatly limit their applications. In order to enhance the heat resistance and endow functionality of NIPUs, a series of PUs (PCUPs) were synthesized in this paper by melt polycondensation reaction using dimethyl carbonate, 1,6-hexanediol, 1,6-hexanediamine, and nontoxic polydimethylsiloxane (PDMS) as raw materials. The thermal, mechanical properties, water absorption, and anti-graffiti resistance of PCUPs were studied. The experimental results showed that the thermal, mechanical, and graffiti resistance properties of PCUPs were improved by adjusting the content of PDMS. The synthesized PCUPs had excellent mechanical properties with a tensile strength of 38 MPa and an elongation at break of 240% due to the formation of microphase-separated structures promoted by PDMS. After three times of hot compression molding, it still maintains good mechanical properties (87%). In addition, the heat deflection temperature of PCUPs increased from 40.3 to 65.2 °C. Surprisingly, the water contact angle of the PCUP film was 104.7°, showing excellent hydrophobicity and satisfactory graffiti resistance behavior. This study provides a perspective on the functional design of environmentally friendly nonisocyanate polyurethanes.