Macromolecular Rapid Communications最新文献

Front Cover: Racemic octahedral metal complexes with Δ and Λ chirality have been reported as the first octahedral metallomesogens to exhibit a micellar cubic liquid crystal phase. Furthermore, quasi-racemic mixtures, a 1:1 mixture of Δ -Ru-Cn and Λ -Ir-Cn, also exhibit the CubM phase and display unique vibrational circular dichroism signals that are not observed in pure enantiomers. More details can be found in the Research Article by Go Watanabe, Mitsuo Hara, Jun Yoshida, and co-workers (DOI: 10.1002/marc.202500485).

The synthesis of high-performance hydrogel adhesives often relies on complex, multi-component systems, complicating their preparation and application. To overcome these limitations, we report a thermosensitive nanogel adhesive (NGA) via a facile one-step precipitation polymerization of N-isopropylacrylamide (NIPAM) and 3-acrylamidophenylboronic acid (AAPBA). This NGA functions as a simple adhesive, forming stable bonds with hydroxyl-rich substrates without requiring additional curing steps. The resulting nanogel exhibits dual sensitivity to temperature and pH, undergoing reversible changes and gelation under specific conditions. Mechanical interfacial bonding tests of hydrogel substrates reveal that a minimal volume of 15 µL of the NGA dispersion achieves a shear strength of 7.0 ± 1.4 kPa and a tensile strength of 15.7 ± 4.2 kPa. Furthermore, the adhesion performance can be precisely tuned by controlling the nanogel particle size, dispersion pH, and concentration. Biocompatibility assessments confirm excellent hemocompatibility and cell viability. This work not only presents a robust and tunable nanogel adhesive platform but also establishes a general model for the design of functional nanogel-based adhesives, significantly expanding their potential applications.

Tropolone is one of the non-benzenoid aromatic compounds and consists of a seven-membered ring with 6π electrons. Although its photophysical properties involving light absorption and photoluminescence (PL) spectra have been investigated, there are limited number of systematic studies on unveiling structure-photophysical property relationships because its absorption and luminescence are relatively weak. We have recently reported that boron complexes with tropolone derivatives and their π-conjugated polymers exhibit enhanced absorption and PL properties derived from the significant electron-accepting ability originating from the seven-membered ring. Herein, we attempt to reveal the versatility of polymerization/oligomerization for amplifying photophysical properties of tropolone-based boron complexes. In this study, we synthesized the boron complexes with arylaminotropones, where one of the oxygen atoms of tropolone is converted to nitrogen, offering a handle to tune properties, and examined the electronic properties of its oligomers as well as small molecules. It was found that amination of the coordination site caused the bathochromic shifts of absorption and PL bands with a decrease in PL quantum yield (PLQY). Moreover, compared to boron tropolonate derivatives, the absorption and PL spectra showed a bathochromic shift, and PLQY was improved by oligomerization, indicating that the oligomerization might enhance the opportunity of tropolone-based compounds for photophysical applications.

The use of non-renewable petrochemical feedstocks for the production of specialty polymer materials is not a sustainable practice. However, the use of waste commodity thermoplastic polymers as a feedstock for the production of specialty monomers is an attractive alternative. In this work, we show that high molar mass polybutadiene can be upcycled into reprocessable thermoset materials that can be recycled and reshaped multiple times as a dynamic covalent polymer network (DCPN). First, a one-pot partial hydrogenation and ethenolysis protocol was used to chemically cleave polybutadiene chains into low molecular weight α,ω-dienes. These were subsequently incorporated in a thiol-ene cured thermoset material using multifunctional thiols. The thioether linkages, connecting the polyolefin segments, can be turned into covalent dynamic moieties upon alkylation at elevated temperatures. The dynamic behavior of these thioether linkages was demonstrated through rheological and reprocessing experiments at elevated temperatures, highlighting their potential for sustainable material design. This strategy has a clear potential for an "upcycling" paradigm of bulk polymer waste into specialty polyolefin-based thermosets and DCPNs with appealing recyclability potential.

Heteroatom incorporation is a general strategy toward advanced polymer properties. We report here efficient synthesis of polymers containing, site-specifically, at least four different heteroatoms (O, N, S, F) by copolymerization of isothiocyanate (ITC) and trifluoropropylene oxide (TFPO). Unlike the regular non-fluorinated epoxides for which Lewis pair catalysts are needed, the superior activity of TFPO allows the use of only organobases, even the relatively mild ones, to reach high/complete monomer conversion in hours at room temperature and low catalyst loadings (0.01-0.1 mol.%). With optimal initiator structure and monomer feed ratio (1/1), alternating copolymers, i.e. fluorinated polythioimidocarbonates (^FPTCs), with controlled molar mass and low dispersity are obtained. Copolymerization with alkyl and allyl ITCs are remarkably more chemoselective, which is ascribed to the alleviated nucleophilicity of the oxyanionic species and expedited S-to-O crossover. While thermostability of the aromatic PTC is evidently improved and adhesive strength unaffected by the CF₃ groups, depolymerization becomes much easier under basic conditions, selectively forming a five-membered cyclic thioimidocarbonate.

Supramolecular polymers are a class of dynamic materials with varied applications in material science and biomaterials. The quality and nature of solvent are often used to control various aspects of supramolecular polymerization. A vast majority of monomers or building blocks are known to assemble in a single solvent, which promotes intermolecular interactions. A small fraction of monomers requires a combination of solvent and anti-solvent to promote colloidal assembly. In the past decade, examples are emerging in which the solvents seem to exhibit specific roles in controlling the assembly, beyond the conventional solvent/anti-solvent modes. In this perspective, we discuss recent examples in which solvents seem to play an unconventional role in dictating supramolecular polymerization. Often, the unique assembly behavior is attributed to the thermodynamics of binary mixture governing the solvation. We envisage that the specific interaction between the monomer and solvent warrants a careful consideration, in addition to the solvent-solvent interactions to account for the perceived special effects of the solvents.

Hydrogels, as a representative substrate for flexible sensors, often exhibit compromised mechanical strength and environmental instability owing to insufficient molecular chain interactions. To address such grand challenges, we propose a strategy here for fabricating highly entangled MXene (2D transition metal carbides)-polyacrylamide organic hydrogel (HTO-MPM), which shows excellent extensibility and toughness. Due to the sliding properties of highly entangled polymer long chains and the low friction sliding between chains, the hydrogels show excellent strength, toughness, and low hysteresis. Moreover, MXene acts as physical crosslinking points in the entangled hydrogel, enabling polymer chains to further slide along the stretching direction. Meanwhile, its mechanical strength and water retention are strengthened by forming strong hydrogen bonds. The HTO-MPM achieves low hysteresis (<6%), high stretchability (>1700%). Thus, the hydrogel sensors maintain stable performance over 5,000 strain cycles. These combined properties render the conductive gel a promising candidate for flexible sensing components in wearable device applications.

Owing the complex anatomy and multiple physiological barriers, delivering drugs to the posterior segment of the eye remains challenging. While intravitreal injection can improve drug delivery, the diffusion of therapeutics through the vitreous humor and their uptake by the retina remain limited due to the anionic nature of the vitreous humor, attributed to its collagen and glycosaminoglycan content. Poly(solketal acrylate)-based nanoparticles (PSA-NPs) were developed via single-emulsion solvent evaporation and nanoprecipitation techniques and loaded with Nile red (NR-PSA-NPs) as a hydrophobic drug model, enabling in vitro and ex vivo tracking via fluorescence microscopy. These NPs exhibit a neutral to negative surface charge, enhancing their distribution through the vitreous humor. Evaluating these NPs for drug delivery, cytotoxicity studies using retinal cells confirmed their excellent nontoxic profiles. Additionally, fluorescence microscopy and FACS analysis revealed a significant increase in the uptake of NR-PSA-NPs in ARPE-19 cells (human retinal pigment epithelial cell line) compared to that of free dye. Moreover, incubation of NR-PSA-NPs with retinal organ cultures and their intravitreal injection into whole porcine eyes showed red fluorescence across all retinal layers, confirming successful uptake, distribution, and widespread retinal penetration, making these NPs promising carriers for delivering hydrophobic drugs to the posterior eye segment.

Size-exclusion chromatography (SEC) equipped with refractive index (RI) and multi-angle light scattering (MALS) detectors was carried out on a polystyrene (PS) sample with the weight-average molecular weight 2.07 ×€10⁴ along with the matrix-assisted laser desorption flight time mass spectrometry (MALDI-TOF-MS). The MALDI-TO-MS result was corrected by the relative sensitivity, which was found to decay exponentially with the molecular weight. Exchanging the elution volume for molecular weight by the calibration relation, the molecular-weight distribution (MWD) curves were obtained from the chromatograms. The MWD curve determined by the SEC chromatogram was much broader than that obtained by MALS and MALDI-TOF-MS because of the peak-broadening effect. Based on the MWD determined by MALDI-TOF-MS, the RI chromatogram was closely described by the calculated values using the Gaussian function. Based on the results of the PS sample, RI and MALS data of polyethylene oxide samples in water were analyzed using the exponentially modified Gaussian equation.