Macromolecular Rapid Communications最新文献

Electrospun fibrous materials with fine fibers and small pores are fundamental for particulate matter (PM) filtration, addressing its harmful environmental and health impacts. However, the existing electrospun fibers are still limited to their sub-micron diameters and unstable surface electrostatic effect, leading to deteriorated filtration performance after prolonged storage or wetting. Herein, the study creates nanofibrous membranes with long-time stable electrostatics by electret-enhanced electrospinning. The phase separation and polarization of the charged jet are manipulated to achieve rapid stretch and strong electret. The obtained membrane exhibits nanosized structures with fiber diameters of ≈220 nm, pore size <1 µm, as well as robust surface potential of 0.4 kV. By virtue of the synergistic effects of sieving and adsorption, the nanofibrous membrane showed a remarkable PM_0.3 filtration efficiency of 96.6% and pressure drop of 140 Pa, even reaching the N90 standard after five wetting cycles. The design of such durable membranes will offer a new sight in the functional filtration materials.

Critical issues such as leakage, degradation, and thermal response hysteresis have become the focus in the application of phase change materials (PCMs) in area such as thermal management of fabrics. The encapsulation of PCMs prepared as microcapsules using polysiloxanes, etc. as a component unit of crosslinking agents represents a highly promising avenue of research. In this work, organosilicon crosslinkers are prepared and employed for the crosslinking of poly (methyl methacrylate) (PMMA) for microencapsulation of paraffin wax in microcapsule phase change materials (mPCMs). The results showed that increasing the degree of crosslinking helps to improve the performance of mPCMs by smoothing the shell surface, but excessive crosslinking leads to flocculation, which reduces its performance. The mPCMs produced with 10% wt crosslinking agent gave the highest performance with encapsulation efficiency, melting enthalpy and crystallization enthalpy of 81.3%, 285.0 J g^-1 and 253.1 J g^-1, respectively. The obtained mPCMs are also combined with epoxy resin and fabrics to form composite materials. Notably, the polysiloxane-modified mPCMs permit epoxy resins to achieve a maximum temperature reduction of 25 °C. By adjusting the mass ratio of organosilicon crosslinkers, the obtained mPCMs enable textiles to reach a maximum temperature reduction of 17 °C while maintaining satisfactory air permeability.

Back Cover: This cover illustrates the pivotal role of water in creating a dynamic link between the hydroxypropyl cellulose polymer and organic solvents in gel polymer electrolytes. The innovative use of water as both a plasticizer and cosolvent enhances the performance of dye-sensitized solar cells. More details can be found in article 2400481 by Z. L. Goh, Shahid Bashir, K. Ramesh, S. Ramesh, and co-workers.

Front Cover: The image shows micro-phase separation in β-Ocimene–Styrene and β-Myrcene-Styrene copolymers, as studied in the article 2400641 by Carmine Capacchione, Finizia Auriemma, and co-workers. The tendency of styrene and terpene-rich sequences to give heterogeneities with correlation strength extending over 10–40 nm is outlined. The complex glass transition dynamics is also evidenced by the physical aging experienced by the amorphous phase in styrene-rich copolymers.

Lignin's complex and heterogeneous molecular structure poses significant challenges for accurate molar mass determination, which is important for its utilization in industrial applications, such as biochemicals, nanoparticles, biobased binders, and biofuels. This study evaluates the potential of Taylor Dispersion Analysis (TDA) for measuring lignin size and compares it with size-exclusion chromatography (SEC) and diffusion-ordered spectroscopy (DOSY) NMR. Using dual Gaussian fitting, flow-induced dispersion analysis (FIDA), a TDA-based method, successfully determined the average hydrodynamic radii of multiple species in solvent-fractionated soda grass lignin samples, producing results consistent with DOSY. Molar mass calibration enabled comparisons between FIDA and SEC, revealing similar relative differences across lignin fractions. FIDA offers advantages such as rapid analysis and absence of stationary phase interactions, however its accuracy is limited by the variability of lignin fluorescence. Addressing these limitations will be critical for advancing FIDA as a method for lignin size estimation.

A novel PLGA-inspired NP polymerization technique is presented, which allows the formation of NPs via the cross-linking of precisely sequenced short oligolactoglycolic acid dimethacrylates (OLGADMAs). Following the synthesis of a range of OLGADMAs, a library of NPs via this rapid and surfactant-free nanopolymerization method is successfully generated, which permits the simultaneous NP formation and encapsulation of drugs such as dexamethasone. The results indicate that NPs produced through this nanopolymerization technique with precisely controlled sequences exhibit heightened stability compared to conventionally sequenced and non-sequence controlled PLGA, as evidenced by minimal pH changes over five weeks. This improved stability is attributed to simultaneous crosslinking and co-polymerization of the OLGADMAs. Moreover, the long-acting NPs demonstrate minimal cytotoxicity and uniform cellular uptake in vitro. It is concluded that the ability to precisely regulate the sequence of short PLGA-inspired monomers and employ a unique in situ nanopolymerizing reaction results in exceptionally stable NPs for sustained drug delivery and opens exciting possibilities for the development of a range of long-lasting drug delivery systems with programmable structure and function.

Flexible electrochromic devices (FECD) have been widely applied in smart displays, wearable devices, and other fields, however, the synchronous improvement of electrochromic performance and flexibility is still a challenge. In this paper, a fabric-based FECD with "side-by-side" structure is designed and constructed through inkjet printing. The polyaniline nanosheets with good dispersion are used as ink and electrochromic material, and the self-developed semi-solid electrolyte based on polyvinyl alcohol serves as gel electrolyte. Benefiting from the improved structure and excellent performance of individual components, the obtained FECD achieves a reflectivity change of 22.9%, and maintains the electrochromic ability after bending for 1000 times. This shows the potential in the field of wearable smart clothing and other flexible textile displays.

Within the context of polypropylene recycling by dissolution, the potential degradation of polypropylene in solution has been investigated using in situ NIR and Raman spectroscopy. Pure polypropylene, completely free of additives, and commercial polypropylene, low in additives, are degraded on purpose under different conditions. Genetic algorithm combined with partial least squares (GA-PLS) models have been built based on near-infrared (NIR) spectra, and partial least squares (PLS) models based on Raman spectra, to predict the mass average molar mass and the chain-scission rate, respectively, during the degradation process. The variables used in the GA-PLS model from NIR spectra suggest that the main variability is related to physical changes via the baseline. In Raman, a baseline drift due to coloration during the degradation has been used to correlate the spectra with the degradation phenomenon. Both techniques show good predictive performances and can potentially be implemented for real-time supervision of degradation during recycling processes.

Aggregation-induced emission (AIE) materials have gained significant attention for their unique fluorescence enhancement in the aggregated state. However, combining rigid polymers with AIE molecules to enhance luminescent properties remains to be investigated. In this work, two novel AIE-active polyarylethersulfone (PAES) derivatives are synthesized by incorporating tetraphenylethene (TPE) into either the side chain or main chain of PAES, resulting in side-chain polyarylethersulfone-tetraphenylethene (PAES-TPE) and main-chain polyarylethersulfone-tetraphenylethene (m-PAES-TPE), respectively. These derivatives are designed to investigate the influence of the rigid polymer backbone on the AIE properties of TPE. The incorporation of TPE into PAES resulted in a notable redshift in fluorescence emission compared to pure TPE. Notably, m-PAES-TPE_50%, a polymer with 50% molar content of TPE, exhibited a fluorescence quantum yield to 57.43%, more than twice that of TPE powder. Thermal analysis showed that both PAES-TPE and m-PAES-TPE have excellent thermal stability and temperature-dependent fluorescence. Additionally, these materials are processed into hydrophobic nanoparticles, and in vitro experiments demonstrated good fluorescence properties and biocompatibility for cancer cell bioimaging. This work highlights the potential of rigid AIE-active PAES derivatives for advanced bioimaging applications.