Macromolecular Rapid Communications最新文献

Sustainable production of polylactide demands catalysts that are both recoverable and capable of delivering precise molar mass and stereocontrol. A series of heterobimetallic complexes [(THF)NaFe(OtBu)₃]₂, [(THF)₂KFe(OtBu)₃]₂, [KZn(OtBu)₃]₂, [(THF)KCu(OtBu)₃]_∞ and [(THF)KCo(OtBu)₃]₂ was evaluated as precursors for heterogeneous catalysts by grafting onto dehydroxylated silica. All complexes demonstrated activity in the ring-opening polymerization of lactide. Notably, the silica-supported [(THF)KFe(OtBu)₂]_/SiO_2-700 and [(THF)NaFe(OtBu)₂]_/SiO_2-700 systems exhibited high efficiency, promising recyclability, and afforded predictable molar masses (M_n,exp close to M_n,th) with narrow dispersities. These findings highlight new opportunities for designing recyclable catalysts for sustainable PLA synthesis.

The spontaneous transformation in isotactic poly(butene) (iPB) of kinetically favored form II into the thermodynamically stable form I at room temperature leads to dimensional instability due to changes of density and strength and has prevented industrial development of iPB. This transformation is accelerated by tensile deformation. This study investigates the correlation between the form II-form I transition occurring during tensile deformation and orientation of relative crystallites in 1-butene/ethylene (C4C2) isotactic copolymers. During stretching, form II transforms into form I in all samples. Both the critical strain at which the form II-to-form I transition begins (ε_c) and the strain at which 50% of the initial form II is transformed into form I (ε_0.5) increase with increasing ethylene (C2) content. For samples with C2 content ≤ 7.6 mol%, form II crystals adopt an off-axis orientation at ε_0.5. In contrast, for higher C2 content, form II crystallites remain isotropic at ε_0.5. Form I crystals adopt an off-axis orientation at ε_0.5 only in the two samples with lowest C2 content (1.7 and 4.3 mol%). Crystals of form II and form I begin to orient in the standard fiber orientation at progressively earlier stages of the form II-to-form I transition as the ethylene content increases.

Rubber materials, with finely tunable chain structures and crosslinked networks, exhibit outstanding flexibility, strength, stability, and versatile functions. These attractive features enable their wide-range use from household goods to high-performance industrial products. With the rise of flexible electronic devices, conductive and flexible rubbers are receiving tremendous attention since they simultaneously possess excellent flexibility and conductivity. In this manuscript, we aim to review the recent advances in conductive rubber composites, covering material selection, conductive mechanisms, interfacial engineering, processing techniques, vulcanization strategies, and applications. Current challenges, including filler dispersion, large-scale production, conductivity stability, and environmental concerns, are critically discussed, along with emerging directions such as self-healing conductive rubbers, sustainable bioderived filler-based systems, and superhydrophobic properties. The integration of innovative material design with scalable, low-cost, and eco-friendly manufacturing is expected to promote the future development of conductive and flexible rubbers.

Polyesterurethanes are versatile polymers widely utilized in applications such as foams and adhesives, yet their industrial production relies on toxic and carcinogenic diisocyanates. To address this, isocyanate- and phosgene-free synthetic methods have been explored, with ring-opening polymerization of cyclic carbamates emerging as a promising alternative. This study presents the coordinative ring-opening copolymerization of limonene-based cyclic carbamates with ε-caprolactone to synthesize AB-block polyesterurethanes. Using the presented method, tunable block copolymer compositions were achieved, verified by NMR, GPC, and FT-IR analyses. Thermal and optical characterizations by DSC and UV-vis revealed an adjustable glass transition temperature between -9°C and -59°C and transmittance up to 84% for PLU-b-PCL (49:51), while tensile testing demonstrated customizable mechanical properties. Notably, PLU-b-PCL (5:95) exhibited an elongation at break of 582%. These findings provide a basis for sustainable polyesterurethane synthesis by ring-opening copolymerization and demonstrate the versatility of this method.

Pseudomonas aeruginosa forms biofilms that complicate treatment of infections, with lectins LecA and LecB playing crucial roles in this process. This study investigates the inhibitory effect of glycosylated nanogels on lectin binding and biofilm formation. Nanogels presenting melibiose (α-galactose) and fucose (β-fucose) effectively reduce LecA and LecB binding, respectively, in competitive inhibition assays against immobilized glycoproteins. Melibiose nanogels are more potent inhibitors than fucose nanogels, as α-galactose is more strongly bound by LecA than β-fucose by LecB. Both types of glycogels have a high impact on P. aeruginosa biofilm formation. Notably, the timing of glycogel application significantly influences biofilm dynamics; pre-treatment leads to a 75% reduction in biofilm formation, whereas treatment after biofilm initiation results in a 60% increase in biofilm growth, suggesting that these glycogels can act as both inhibitors and enhancers of biofilm development. The findings highlight the complexity of carbohydrate-based interactions in biofilm modulation and underscore the necessity for precise dosing and structural optimization in developing effective strategies against infections caused by biofilm-forming bacteria.

Small-molecule drugs are crucial to human health. Yet, they often suffer from their low stability, poor water solubility, significant side effects, and rapid clearance rate from the human body, which limit their therapeutic efficacy in the treatment of chronic diseases. To address these issues, researchers have proposed the strategy of developing polymeric drugs. Multicomponent reactions (MCRs) are characterized by facile operation, modular reaction, and functional products, and have been served as powerful tools for synthesizing polymeric drugs. In this mini-review, we mainly summarize recent studies of polymeric drugs based on MCRs. These polymer drugs have been applied in various fields as antioxidants, antitumor agents, metal chelators, and theranostic medicines. Meanwhile, we discuss the limitations of these studies and provide an outlook on future research trends.

Deformation of glassy polymers induces plastic flow as a result of mechanical instability, ultimately leading to cavitation and fracture of the liquid. Thus, understanding the origin of such mechanical instability is crucial. Here, we demonstrate that strain deformation of polymeric glass is accompanied by marked shear-thinning behavior and leads to enhanced density fluctuations. These results are consistent with Furukawa and Tanaka's theory, which predicts that strain induces the self-amplification of the density fluctuations. Thus, we conclude that the enhancement results from the coupling between the velocity field and density fluctuations, stemming from the Furukawa and Tanaka theory, glassy polymer, small-angle X-ray scatteringstrong density dependence of viscosity.

The interfacial assembly and rearrangement of nanomaterials are critical for stabilizing air-water/oil-water interfaces. Cellulose nanofibers (CNFs) are promising renewable bio-based solid surfactants that form stable interfacial layers separating the fluid interface. However, the correlations between microstructural features (e.g., defects, orientation, buckling) and physicochemical properties of the interfacial layer remain unclear. This study attempted to understand the interfacial behaviors of CNFs with different hydrophobicity through a common mechanism. First, nanofiber monolayers were fabricated on the water surface of a Langmuir trough. Three different regions corresponding to gaseous, liquid expanded, and liquid condensed films were determined from the characteristic points of surface pressure isotherms. The film structures and their surface dilatational storage/loss moduli exhibited significant changes across these three regions. Overall, we propose that the interfacial behaviors of nanofiber monolayers can be organized by macroscopic wettability of nanofibers which is readily measurable. These results provide insights into the interfacial stabilization mechanism of fibrous nanomaterials and pave the way for applications in functional Pickering emulsions/foams.

High-emission coatings are the focus of significant attention for their efficient thermal protection in aerospace applications. Aluminum-chromium phosphate solution (ACP) was synthesized in this study by utilizing H₃PO₄, Al(OH)₃, CrO_3, and CH₃OH as raw materials. Subsequently, a room-temperature curing high-emissivity coating was effectively developed by employing ACP as the binder, Mg-MOF-74 as the curing agent, SiC and ZrB₂ as radiating agents, and Al₂O₃ and ZrO₂ as high-temperature stabilizers. Consequently, the coating exhibited exceptional thermal stability and radiation performance, with a mass residue rate of 98.71% after exposure to 1500°C. And the emissivity exceeded 0.93 at room temperature and measured ε _{(3-8 µm)} = 0.84 and ε _(8-18 µm) = 0.9 after treatment at 1200°C. Thus, the coating developed in this study provides durable and highly effective thermal protection under high-temperature conditions.

Flexible perovskite solar cells (FPSCs) are promising candidates due to their lightweight, bendable form factor and potential for integration into wearable and portable electronics. However, their commercialization is still hindered by both intrinsic and extrinsic instabilities, as well as performance losses under external stress. Polymers have proven to be key enablers in addressing these challenges by promoting crystal growth, improving interfacial contact, and reinforcing device structure. This review highlights polymer design strategies that enhance mechanical flexibility, environmental stability, defect passivation, and perovskite film crystallinity. State-of-the-art solutions and benchmark approaches are summarized to showcase recent progress in achieving high power conversion efficiency (PCE) retention over extended bending cycles. Finally, future research directions in polymer selection and design are discussed, with particular emphasis on the emerging role of machine learning for polymer optimization. Hence, this review emphasizes the critical role of polymers in advancing the development of FPSCs.