Macromolecular Rapid Communications最新文献

Polysiloxanes and silsesquioxanes (SQs) are known to be insulating materials. We describe here polysiloxane copolymers where this is not the case. Thus,Me₂VinylSi─O─SiMe₂Vinyl/Br-Ar-Br copolymers exhibit conjugation via Si─O─Si bonds contrary to the widespread understanding that such linkages must be insulating. Here we describe the synthesis, characterization, and photophysical properties of [-VinylSiMe₂OMe₂SiVinyl-Ar]x copolymers; Ar = phenyl, terphenyl, stilbene, thiophene, etc. Con-jugation is evidenced by redshifted emission λ_max of copolymers vs model compounds, [(MeO)₂SiMeVinyl-Ar-VinylMeSi(OMe)₂], electron transfer to F4TCNQ and MW (DP) depend-ent emission red-shifts (smaller bandgaps with increasing DP). Theoretical calculations targeting electronic structure, absorbance/emission λ_max of model com-pounds vs oligomers support conjugation via π-dπ^* orbital interactions. In the ground state, model compounds offer Si─O─Si bond angles of ≈110° on average. In the copolymers, bond angles change in the ground state averaging ≈ 140 ° and in the excited state approach 150 ° much closer to planarity, a result of conjugation. Here SiOSi bonds facilitate intersystem charge transfer (ICT) as seen in carbon based polymers. Thus, i.e, ICT in VySiOSiVycoPh likely leads to a much larger Stokes shift (≈115 nm) than in the silane model. Our findings provide the first detailed photophys-ical studies of conjugation in polysiloxane-chromophore copolymers.

This study explores the development of a photo-responsive bicomponent electrospun platform and its drug delivery capabilities. This platform is composed of two polymers of poly(lactide-co-glycolide) (PLGA) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). Then, the platform is decorated with plasmonic gold nanostars (Au NSs) that are capable of on-demand drug release. Using Rhodamine-B (RhB) as a model drug, the drug release behavior of the bi-polymer system is compared versus homopolymer fibers. The RhB is incorporated in the PHBV part of the platform, which provides a more sustained drug release, both in the absence and presence of near-infrared (NIR) irradiation. Under NIR exposure, thermal imaging reveals a notable increase in surface temperature, facilitating enhanced drug release. Furthermore, the platform demonstrates on-demand drug release upon multiple NIR irradiation cycles. This platform offers a promising approach for stimuli-responsive drug delivery, making it a strong candidate for on-demand therapy applications.

As technology has developed by leaps and bounds over decades, the development of high-performance supramolecular adhesives has become crucial in both scientific and industrial fields. Ionic liquids (ILs)-based adhesives, containing ILs segment, utilizing ILs chemical structure as either the primary adhesive component or key functional group, have materialized as a highly transformative subject matter for cutting-edge and emerging applications. Rational adhesive design strategies, carefully balancing adhesion and cohesion behavior, are also required when constructing ILs-based adhesives. Herein, a detailed discussion on the latest advancements is provided in ILs-based adhesive design, including strategies such as IL monomer decoration/polymerization and the creation of ionogels, etc. Leveraging abundant toolbox of ILs structure and obtained rich (macro)molecular configuration, these adhesives can address both general and specific requirements, offering distinctive advantages and great potential for practical industrial applications. From this perspective, it outlines and summarizes the recent research including rational design and manufacturing technique toward advanced ILs-based adhesives such as sensory, underwater, electric-controlled and biomedical applications, particularly proposing the guidance for construction toward tailor-made glues.

Biodegradable antimicrobial gauzes are environmentally friendly medical dressings taking essential role in the protection and healing of wounds. Poly (butylene adipate terephthalate) (PBAT) offers a promising platform for exploiting biodegradable antimicrobial gauzes attributed to its exceptional biodegradability, biocompatibility, processability, and flexibility. To date, most work is focused on utilizing electrostatic spinning to fabricate PBAT antimicrobial gauzes. The PBAT antimicrobial gauzes exhibit unsatisfactory tensile strength and breaking elongation restricting their practical application. Moreover, electrostatic spinning technology requires high-cost equipment and presents relatively lower production efficiency which is not suitable for large-scale production. Herein, a dry spinning technology is reported that can manufacture PBAT fibers with superb mechanical properties (tensile strength 14 MPa, breaking elongation 1600%) in large-scale and high-efficiency (151 m·min^-1). The antimicrobial gauzes are achieved by loading commercially available and used antibacterial agent, tannic acid (TA), to the surface of the textiles prepared from the PBAT fibers by the traditional knitting process. The antibacterial result demonstrates that the developed antimicrobial gauzes display a remarkable inhibitory effect on the growth the Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) which are common bacteria that cause wound infections.

Two fluorinated monomers M1 and M2 based on pentafluorostyrene, are synthesized via an aromatic nucleophilic substitution reaction (SNAr) at room temperature, with high yields of up to 90%. Subsequently, M1 and M2 are converted to fluorinated poly(aryl ether)s through thermo-crosslinking. Among the two polymers, cured M2 possessing higher fluorine content, demonstrates superior overall performance with a 5% weight loss temperature (T_5d) of 465 °C, a low water uptake of 0.17% (after immersing in boiling water for 72 h), a low dielectric constant (D_k) of 2.46 and dielectric loss (D_f) of 3.65 × 10^-3 at 10 GHz. These properties outperform those of numerous poly(aryl ether)s and commercially available low-dielectric materials. This study provides a facile and effective method for preparing fluorinated poly(aryl ether)s tailored specifically for high-frequency communication applications.

Investigating the swelling behavior of superabsorbent polymer microparticles (SAP-MPs) at a single-particle level using traditional methods is constrained by low resolution and insufficient real-time data, especially for particles smaller than 300 µm. To address these challenges, a novel microfluidic device capable is developed of real-time, high-precision single-particle analysis. This platform hydrodynamically traps individual SAP-MPs, enabling continuous monitoring of their swelling dynamics under controlled conditions. SAP-MPs with varying sizes (90-270 µm), crosslinker concentrations (0.25%2>0.98) and minimal equilibrium volumetric swelling ratio deviations (ΔVSR_eq<4%), confirming diffusion as the primary swelling mechanism, particularly for smaller particles. Smaller SAP-MPs exhibited enhanced performance, with VSR_eq of ≈140 m³/m³-40% higher than their larger counterparts-and swelling rates (SR) up to 10 m³ m^{- 3}·s. This study establishes microfluidics as a transformative tool for single-particle characterization and provides insights into engineering hydrogels tailored for advanced applications in drug delivery, tissue engineering, and environmental sensing.

A series of water-soluble, PEG-based single-chain cyclized/knotted polymers are successfully synthesized through the homopolymerization of poly(ethylene glycol) diacrylate (PEGDA) (M_n  = 575 and 700 g mol^-1, respectively) via enhanced intramolecular cyclization. The homopolymerization of the diacrylate macromers first proceeds through linear propagation, followed by self-cyclization. Under high monomer-to-initiator ratios (e.g., 100-500) and room temperature, cyclized polymers with high cyclized ratios of up to 70% are achieved without gelation. Notably, the cyclized poly(PEGDA₅₇₅) exhibits concentration-dependent thermoresponsive properties in aqueous solutions.

This study explores the performance and stability of ammonium and phosphonium-based polymeric ionic liquids (PILs) with methyl and butyl substituents in moisture-swing direct air capture of CO₂. The polymers are synthesized with chloride counterions, followed by ion exchange to the bicarbonate ion, and tests for CO₂ capture capacity and stability under cyclic wet-dry conditions. The phosphonium polymer with methyl substituents [PVBT-MeP] demonstrates the highest CO₂ capture capacity at ≈510 µmol g⁻¹, attributed to minimal steric hindrance and stronger ion pairing with bicarbonate. However, oxidative degradation is detected by ³¹P NMR spectroscopy after the moisture swing experiment, with the appearance of a phosphine oxide peak at 61.28 ppm, which indicates phosphorus oxidation as the primary degradation pathway. In contrast, the ammonium polymer with butyl substituents [PVBT-BuN] exhibits the highest stability, showing no degradation over five moisture swing cycles. Additional stability experiments in 0.5 m KHCO₃ solutions reveal no degradation for any PIL, suggesting that oxidative degradation is driven by dynamic acid-base reactions during the moisture swing cycles in the air. These findings reveal the potential of phosphonium-based PILs for moisture-swing direct air capture, achieving high capacity while highlighting the need for optimized stability through counterion and structural design.

This work develops the Leather/SSG composite with a laminated structure that consists of flexible leather and rate-dependent shear stiffening gel (SSG), which exhibits superior impact resistance and shock wave protection performance. The SSG is tightly bound to the leather fiber network through hydrogen bonding interactions between the interfaces. Owing to the phase change energy absorption effect of SSG and the synergizing impact force dispersion along the disordered fibers, the Leather/SSG can effectively alleviate the impact force (52%) and shows high energy absorption (0.86-0.95). Besides, Leather/SSG exhibits strain rate enhancement effects with high strain rate impact and it can effectively dissipate stress wave energy by blocking the transmission of stress waves. Moreover, due to the interface structure of soft-hard transition, the Leather/SSG effectively reduces shock wave pressure and positive impulse under the explosive loading. Simultaneously, the influence of impact sequence in Leather/SSG on impact resistance and shock wave absorption is analyzed, confirming the advantage of the leather fiber side being impacted first. These results can provide an important theoretical basis and experimental reference for designing soft/hard impact-resistant composite structures.

Electrospun fish gelatin (FGel) nanofibers (NF) mimic the natural bodies extracellular matrix's (ECM) structure and are an attractive material for many biomedical applications. However, FGel poor mechanical properties and rapid dissolution in an aqueous media paired with usually low productivity of the typical electrospinning process necessitate further effort in overcoming these issues. In this study, alternating field electrospinning (AFES) fabricates cold water fish skin gelatin nanofibrous materials (FGel NFM) with up to 10 wt.% Dextran (DEX) or acetyl glucosamine (AGA) from pure aqueous solutions at process productivity of 7.92-8.90 g∙h^-1. Thermal crosslinking of as-spun materials resulted in FGel-based NFM with 125-325 nm fiber diameters. DEX (MW500k and MW75k) and AGA additives cause different effects on FGel fiber diameters, structure, tensile and degradation behavior, and in vitro performance. All tested materials reveal favorable, but not the same, cellular response through the formation of a confluent layer on the NFM surface regardless of the fibers' composition despite the significant difference in FGel NFM structure and properties. Results show that AFES and thermal crosslinking of FGel-based NFM can lead to a sustainable "green" fabrication technology of mono- and polysaccharide modified FGel-based NFM scaffolds with the parameters attuned to targeted biomedical applications.