ACS Macro Letters最新文献

Driven by surging demand in battery technologies, the global production of polyvinylidene fluoride (PVDF) urgently requires scalable and efficient synthesis methods. Current batch processes are constrained by mass and heat transfer limitations, causing scalability and efficiency bottlenecks. Here, we introduce a novel continuous flow reactor for the fluorosurfactant-free emulsion polymerization of VDF, utilizing a dense tubular membrane made of Teflon AF-2400 to establish a stable phase boundary. This significantly improves mass and heat transfer, reduces energy use, and enables high space-time yields exceeding 190 kg m^–3 h^–1 at just 15 bar gas pressure. Our approach offers substantial advantages in industrial scalability, consistency in polymer quality, and potential adaptability to other gas–liquid–solid polymerization systems.

Priamine derived from vegetable oil has gradually gained attention due to its flexibility. In this study, priamine 1075 was applied to react with urea to prepare thermoplastic polyurea (PUr) and with biuret to polybiuret (PBU) elastomers via solvent-free and catalyst-free melting polycondensation. The obtained PUr and PBUs possess excellent chain flexibility. The strength of PBU00 achieves 8 MPa which is about twice that of PUr. This indicates that the introduction of biuret function in the backbone is able to enhance the mechanical properties. To further improve the strength of the elastomer, 1,10-decanediamine (DDA) was utilized to enlarge the size of the hard segment and the strength of the obtained polymer (PBU20) increases further to 21 MPa. Interestingly, these elastomers exhibit good energy dissipation efficiency (∼80%) and excellent hydrophobicity (water contact angle ∼ 110°), which makes them suitable to be applied in the fields of energy absorption and hydrophobic coatings.

Chiral communication between mirror-imaged enantiomers is important for the development of homochirality in nature. However, polymers made from racemic mixtures usually show no chiroptical activity. Here, we present a new strategy to create global chirality in statistical racemic copolymers and to switch their chiroptical activity using a 2-fold chiral conflict. Chiroptically active assemblies consisting of racemic building units within two heterochiral segments were constructed via a stepwise statistical polymerization-induced chiral self-assembly (stat-PICSA) method. Furthermore, the stacking patterns and resulting chiroptical activity could be switched by changing the ratio of enantiomeric monomers. This switching exhibited distinct chiral conflict effects: “first come, first served” (FF)/“late-comer lives above” (LA) chiral conflict effects. We expect this 2-fold chiral conflict self-assembly strategy to offer a unique approach for developing chiroptical racemic polymer nanoassemblies and to deepen our understanding of how homochiral structures originate in nature.

The development of efficient and controlled polymerization techniques to synthesize degradable polymers is crucial for advancing sustainable plastics. We report a mild and highly efficient strategy for the synthesis of degradable copolymers via visible light-mediated photoiniferter polymerization. Using a commercially available dithiocarbamate compound as a photoiniferter, we achieved the rapid copolymerization of a lipoic acid derivative with various acrylate and acrylamide monomers under benign blue light irradiation (462 nm) at 40 °C. This method provides exceptional temporal control and yields well-defined copolymers with predictable molecular weights, low dispersities, and tunable disulfide content. The resulting copolymers undergo efficient degradation to low molecular weight oligomers through air oxidation or dithiothreitol reduction. This photoiniferter approach establishes a versatile and sustainable platform for the precise synthesis of degradable polymers from renewable sources and commercially accessible monomers.

Sensors are indispensable in modern society, and their performance depends critically on the sensitive layer. Initiated chemical vapor deposition (iCVD) is a superior technique for fabricating these layers, enabling solvent-free, low-temperature deposition of uniform polymer films onto a wide range of substrates, including flexible and structured surfaces, without compromising their integrity. iCVD-engineered sensitive layers have demonstrated substantial improvements in sensor sensitivity, selectivity, and stability across diverse applications. This viewpoint provides a comprehensive overview of recent advancements in iCVD-assisted sensor fabrication for various applications, including humidity, gas, pH, glucose, fluorescence, and force sensing. By allowing precise control over material properties and interfacial design, iCVD emerges as a versatile and scalable technique for next-generation sensing systems in the environmental monitoring, healthcare, and industrial processes.

Polymer networks have gained great attention due to their unique structural arrangement and characteristic properties. The interconnection of polymer chains can be achieved through covalent or noncovalent interactions. However, it remains a challenge to explore a strategy for the precise integration of covalent and noncovalent cross-linking within polymer network architectures. In this work, we designed and synthesized hydrogen-bonding preorganized arylhydrazone dual-arm monomer 1 (M1) and triarm monomer 2 (M2), which were used to fabricate covalent polymer networks (CPNs), CPN1 and CPN2, via acid-catalyzed macrocyclization. The resulting CPN1 and CPN2 exhibited well-defined electron-rich macrocyclic cavities, enabling subsequent supramolecular cross-linking with bipyridinium guest (BP) to generate supramolecular/covalent polymer networks (SCPNs), SCPN1 and SCPN2. CPN1 formed denser, more flexible films compared to the brittle CPN2, highlighting the importance of appropriate covalent cross-linking density. Importantly, incorporation of BP significantly improved the mechanical properties of the networks, including Young’s modulus, tensile strength, and toughness, demonstrating the effectiveness of host–guest interactions in reinforcing polymer network structures and the potential of macrocycle-driven supramolecular engineering for advanced material design.

Postmodification of commodity polymers offers a promising route to mitigate environmental issues while creating value-added materials. Herein, we report an efficient and mild electrochemical strategy for the aromatic C–H iodination of polystyrene, affording iodinated polystyrene as a versatile macromolecular intermediate through anodically generated I⁺ species as a clean reagent for electrophilic aromatic substitution. The method enables direct iodination of polystyrene with a high degree of functionalization while nearly preserving the degree of polymerization and the narrow molecular weight distribution of the starting polymers, featuring selective modification at the aromatic moiety. Moreover, the strategy shows broad applicability to polystyrene substrates of various molecular weights as well as real-life waste such as expandable polystyrene and plastic spoons. Mechanistic studies were also conducted, disclosing a possible reaction pathway. By combining operational simplicity, environmental friendliness, and application potential, this strategy provides a practical and sustainable route for the up-cycling of polystyrene waste.

In this paper, we report two synthetic strategies to engineer the water/salt sorption selectivity of polymers: tethering polar functional groups to the polymer backbone and increasing the degree of cross-linking. For the first strategy, we found that at a given water content, the dielectric constant of hydrated methacrylate-based polymers functionalized with hydroxyethyl (i.e., two carbon) side chains (XL – p(HEMA-co-GMA) is less than that of hydrated methacrylate-based polymers with hydroxypropyl (i.e., three carbon) side chains (XL – p(HPMA-co-GMA), which contributes to suppressing salt sorption to increase the water/salt sorption selectivity. For the second strategy, we found that forming densely cross-linked polymers that contained only dimethacrylate-based monomers (XLPEGDMA) relative to less densely cross-linked copolymers containing both methacrylate- and dimethacrylate-based comonomers (XL – p(HEMA)) reduced the network mesh size at a given water content, which also suppressed salt sorption and increased the water/salt sorption selectivity. These structure–property results inform the design of advanced materials for desalination membrane applications.

Positional isomerism is a key determinant of mechanical performance in polymer networks, yet its underlying molecular mechanisms remain insufficiently understood. In this work, we employ a multiscale simulation approach─integrating density functional theory with a stochastic coarse-grained reaction model─to investigate how meta- and para-substituted diamine curing agents influence the curing kinetics, network architecture, and mechanical properties of epoxy resins. Simulations reveal that the meta-substituted system exhibits higher ultimate strength and fracture toughness than its para-substituted counterpart, consistent with experimental observations. Mechanistic analysis shows that the enhanced performance of the meta-system stems from strain-induced conformational adaptation within loop structures, facilitated by progressive bond-angle relaxation. This dynamic response promotes energy dissipation and effectively suppresses void growth during deformation. In contrast, the para-system undergoes accelerated failure due to its restricted structural flexibility. Our findings highlight positional isomerism as a powerful molecular design strategy for achieving simultaneous improvements in strength and toughness in epoxy thermosets, providing a foundation for rational material design beyond empirical approaches.