Macromolecular Chemistry and Physics最新文献

Front Cover: In article 2400331, Tatsuo Maruyama and co-workers report clickable plastic surfaces with controllable azide surface density by the simple dip-coating method. The surfaces can easily immobilize functional molecules with alkyne groups via strain-promoted azide-alkyne cycloaddition. They succeed in preparing a linear surface gradient of azide group density and also in micropatterning the surfaces by microcontact printing.

Lightly crosslinked polymeric gel-supported catalysts have the potential to retain the recyclability and ease of product isolation of traditional polymer-supported catalysts, while at the same time, they can provide greater homogeneity of catalytic sites and improved reaction rates, especially in the solvent-swollen state. In the present study, a strategy is devised to covalently anchor a film of swellable crosslinked polymer onto a suitably surface-derivatized glass vial, and have utilized this coating to bind to Cu, Pd, and Au catalysts; these coated vials are then utilized for azide-alkyne click, Suzuki coupling and catalytic reduction reactions, respectively. In all cases, simply stirring the reactant mixture in the vial delivers high yields, and the vials can be rinsed and reused several times with little loss of activity. Several control experiments confirm that the catalysis largely occurred within the coated gel film and is not due to leached-out metal in the reaction medium. Importantly, this strategy can be very useful, when adapted for critical labeling reactions of biomolecules, wherein reactions are often carried out on very small scales, and ease of product isolation with zero contamination is critical.

Epoxy resin (EP) is widely used in coatings, adhesives, and molding materials. EP's high crosslinking density provides a strong modulus but also leads to reduced elongation at break and lower toughness. In this study, bacterial cellulose microgel (BC-M) is employed to toughen EP through in situ polymerization, to form an interpenetrating network with EP. Bacterial cellulose nanofibers (BC-CNF) and ethylated bacterial cellulose microgels (EM) are used as controls to highlight the advantages of the 3D network in enhancing polymer toughness. BC-M demonstrates the most effective toughening performance for EP. At a filler content of 0.3 wt.%, BC-M/EP nanocomposites exhibite significant improvements in mechanical properties, including a fracture strength of 107.8 MPa, strain of 3.53%, Young's modulus of 3.09 GPa, and toughness of 1.98 kJ m⁻³. Compared to EP, these values represent enhancements of 40%, 9.5%, 27.3%, and 58.4%, respectively. Comparisons with BC-CNF/EP and EM/EP nanocomposites clearly demonstrate that BC-M provided superior toughening effects. The exceptional toughening capability of BC-M is attributed to its 3D network structure, which effectively dissipates applied energy, and its strong interfacial interaction with the epoxy matrix through covalent bonding.

In this study, the synthesis of a novel chiral multilayer 3D polymer based on a diether structure is reported. This architecture not only imparts chirality but also facilitates the study of aggregation-induced emission (AIE) and aggregation-induced polarization (AIP). Using various polymerization techniques, multilayered chiral structures are constructed that exhibit significant AIE, marked by increased luminescence upon aggregation, and notable AIP behavior, indicating enhanced optical activity. Comprehensive characterization through spectroscopy and microscopy elucidates the mechanisms behind these phenomena. These findings highlight the potential of diether-based chiral multilayer 3D polymers for advanced optoelectronic and sensor applications, paving the way for multifunctional materials.

Inspired by the highly defined structure of biomacromolecules, e.g. deoxyribonuleic acid (DNA) and proteins, the preparation and characterization of sequence-defined and uniform macromolecules gained interest in polymer chemistry. With the development of various synthetic approaches, the challenge of analyzing and confirming the uniform structures emerged. Here, the investigation on the performance of common analytical instruments for the characterization of uniform macromolecules regarding impurities of ±1 in degree of oligomerization is presented. Thus, different mixtures containing oligomers differing in one repeating unit of oligo(ethylene glycol)s (OEG)s, oligo(phenylene ethynylene)s (OPE)s, and Passerini oligomers, respectively, are synthesized, and analyzed by proton nuclear magnetic resonance spectroscopy (¹H NMR), size exclusion chromatography (SEC), and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS). These results demonstrate the indispensability of a careful characterization using more than one technique for determining uniformity. In particular, the obtained SEC results show that it is a powerful tool for purity determination of low molecular weight oligomers.

Conductive hydrogels possess excellent flexibility, conductivity, and sensing properties, making them important carrier materials for flexible strain sensors. They show promising application prospects in fields such as human motion detection and artificial intelligence. This paper introduces polyaniline (PANI) and glycerol (GL) into the magnesium acrylate (AMgA) monomer and prepares the polymagnesium acrylate/glycerol/polyaniline (PAMgA/GL/PANI) hydrogel by free radical polymerization method. When the addition of PANI is 9 wt.%, the PAMgA/GL/PANI hydrogel exhibits good mechanical properties, with a tensile strength of 0.385 MPa, an elongation at break of up to 505%, a compressive strength of 1.04 MPa, and its room temperature conductivity is 1.437 S m⁻¹. Even after freezing at −20 °C, its conductivity can still reach 1.254 S m⁻¹. When the tensile deformation of this conductive hydrogel reaches 500%, the gauge factor (GF) reaches 10.33. In addition, the PAMgA/GL/PANI hydrogel also has good self-healing, adhesion, and moisture retention. These excellent characteristics make it suitable as a flexible strain sensor that can not only accurately monitor human joint movements and subtle physiological signals but also serve as an encrypted information transmission medium.

Diabetic foot ulcer (DFU) is a very serious side effect among the diabetic patients with substantial clinical and economic consequences. The aim of this study was to investigate the efficacy of cows' milk topical ointment, as an available and cost-effective natural product, on accelerating the healing of DFU. In this randomized controlled clinical trial, patients with grade 1 or 2 DFU were randomly divided into two groups of intervention (n = 50) and control (n = 49). For patients of intervention group, cows' milk 20% topical ointment was applied on the ulcer once daily for two weeks, while a type of novel dressing was used for control group with the same frequency and duration. Both groups received usual standard wound care measures. The percentage of change in the ulcer size and the number of cases with complete wound healing (>90% reduction in the ulcer size) were recorded in the both groups. The ulcer size significantly reduced in both groups on the seventh and 14^th days of intervention; however, the percentage of reduction was significantly higher in the intervention (milk) group compared to control at both time points (44.64 ± 15.98 vs. 24.95 ± 12.78, P < .001; 67.67 ± 22.15 vs. 42.87 ± 19.74, P < .001). Furthermore, although more patients in the intervention group (n = 4, 8%) showed complete healing of the ulcer compared to control (n = 0), the difference was not statistically significant (P = .117). Cow's milk 20% topical ointment improves and accelerates the healing of diabetic foot ulcers. However, more clinical studies are required to confirm these effects.