Macromolecular Rapid Communications最新文献

This study presents a novel approach for the development of antifouling and antibacterial hydrogel coatings for short-term titanium implants to treat bone defects. Such implants provide temporary stabilization during bone healing and are intended to be explanted within a period of 12 months. The novel surface modification prevents complications during implant removal, like injury to tissue, nerves, or tendons due to adhesion to the untreated titanium surface. The coatings combine acrylamide-based hydrogels with photocrosslinkers possessing intrinsic antibacterial properties and anchor groups designed for titanium substrates. Comprehensive in vitro evaluations are conducted to assess the biocompatibility and efficacy of these coatings. The results demonstrate that the water-swellable polymer networks effectively prevent cell and tissue adhesion by their antifouling characteristics without inducing cytotoxicity. Importantly, these coatings also exhibit an intrinsic and non-leaching antibacterial effect covalently incorporated into the molecular framework, which addresses the limitations of current implant coating technologies that often rely on the incorporation of antibiotics or bactericidal agents. As the experimental data conclusively verify the effectiveness of the coatings in inhibiting cell adhesion and bacterial colonization, this technology shows great potential to significantly advance the field of short-term titanium implants.

The kinetically controlled supramolecular polymerization is reported of bisterpyridine-based ligands bearing alanine moieties and alkyl chains, both in the absence and presence of Tb(NO₃)₃, in a DMSO and H₂O mixture (2:8 v/v). R-L¹ and R-L² exhibit helical fiber structures with lengths of several hundred micrometers, both without and with Tb³⁺ ions (3.0 equiv.). The supramolecular polymers form through a cooperative model with a nucleation-elongation mechanism and follow an "on-pathway" polymerization process. Thermodynamic parameters are calculated using the MATLAB of heating curves. The Gibbs free energy (ΔG) of the supramolecular polymer of R-L¹ is nearly identical to that of R-L². In contrast, the stability of the supramolecular polymers is significantly influenced by the presence of Tb³⁺ ions. Furthermore, the addition of seeds to monomeric species R-L¹ accelerated the supramolecular polymerization compared to the process without the seed.

In this study, the first recyclable and reusable polystyrene solid support (resin with functional linker) for Fmoc-based solid phase synthesis (SPS) for the synthesis of sequence-defined oligoamides and peptides is presented. By introducing an acid-labile cyclic acetal linker, efficient oligomer cleavage under mildly acidic conditions comparable to conventional linkers is achieve while also enabling efficient on-resin regeneration of the linker. This regeneration ability allows the support to be reused for multiple synthesis cycles without compromising the flexibility, high reproducibility, and structural control inherent to solid-phase synthesis. As a proof of concept, the robustness of this approach is demonstrated by synthesizing different dimeric structures in an alternating manner on the same resin. For each cycle, the oligomer is first elongated through building block coupling, followed by cleavage from the solid support to release the product. The linker is then regenerated on the functionalized solid support, allowing the cycle to be repeated for the synthesis of subsequent oligomers. This approach maintains high yields and purity across multiple cycles, illustrating the potential as a versatile and more sustainable methodology for Fmoc-based solid phase synthesis.

The development of new high-performance materials in the field of polymer composites is becoming increasingly challenging as the requirements for real-life applications evolve rapidly. In particular, the issue of heat dissipation in a multitude of devices has become a matter of critical importance due to the ever-increasing compaction of electronic devices and the significant growth in power density stored in batteries. This calls for the development of novel solutions to enhance heat dissipation while preserving electrical insulation properties, particularly in light of safety concerns. In this context, polymer nanocomposites can play a significant role, as the incorporation of specific fillers can markedly improve their intrinsic properties, namely, low electrical conductivity, lightweightness, processability, and low cost. New fillers based on a core-shell structure have recently emerged. They are typically nanoscopic in size and synthesized through fine chemical processes to optimize their performance and ensure optimal cohesion with the polymer matrix. Nanocomposites based on core-shell nanofiller yield remarkable and highly promising outcomes, often exceeding the state of the art. This review article presents a comprehensive overview of these nanostructures and their applications, elucidating their significance and results, and discusses their role in achieving optimal heat dissipation.

The functional lactone 2-Methyl-2-propanyl-7-oxo-1,4-oxazepane-4-carboxylate (BocOP), containing a protected secondary amino group, is synthesized through oxone-mediated Baeyer-Villiger oxidation. After that, the homopolymerization kinetics of BocOP catalyzed by immobilized Candida antarctia lipase B (Novozym 435, N435) are investigated. The N435 can efficiently catalyze the conversion of BocOP into poly(β-amino ester) (PAE). Then, the N435 is subsequently employed to synthesize copolymers of BocOP and ε-caprolactone (CL) using methoxypolyethylene glycols (mPEG) as initiators. The study shows that BocOP copolymerized with CL to produce a random PAE copolymer. Following deprotection, the PAE copolymers containing discoverable secondary amino groups demonstrate a preferent bactericidal effect against Gram-negative bacteria. The preference arises from the capacity of PAE copolymers to permeabilize the bacterial outer membrane, subsequently slightly compromising the inner membrane and resulting in the death of Gram-negative bacteria. Furthermore, the PAE copolymers exhibit a comparatively low hemolysis and cytotoxicity.

Inside Front Cover: The cover image of article 2400834 by Finizia Auriemma, Carmine Capacchione, and co-workers illustrates the production of biobased polymers and copolymers using titanium OSSO complexes as catalysts. Monomers such as VCH, IVC (extracted from Perilla plants), myrcene (sourced from Myrcia), and ocimene (present in Basil) are depicted. The artwork highlights the sustainable conversion of plant-derived compounds into stereoregular polymers, showcasing advancements in green and renewable materials science.

Front Cover: A series of polymerizable amphiphilic zwitterions spontaneously formed bicontinuous cubic liquid-crystalline assemblies having a 3D continuous hydrophilic periodic minimal surface. Through in situ polymerization, they were converted to be self-standing polymer films preserving the gyroid nanostructure. The 3D continuous hydrophilic surface in the films functioned as proton conduction pathway transporting proton via highly-activated surface hopping conduction mechanism. More details can be found in article 2400619 by Takahiro Ichikawa and co-workers.

The combination of gold nanoparticles (Au-NPs) and block copolymer (BCP)-based vinylogous urethane vitrimers leads to advanced nanocomposites where the thermal, mechanical, and thermo-mechanical properties are enhanced without interfering with the formation of vinylogous urethane groups and the transamination in the dynamic polymer network. Photoiniferter reversible addition-fragmentation chain transfer polymerization (photoRAFT) and inverse Turkevich synthesis are used in this work to fabricate the desired BCPs and spherical Au-NPs. The key feature of this synthesis is the integration of Au-NPs into the polymer matrix as fixed parts of the hybrid network, ensuring full recyclability. A wide range of properties can be tuned by variations of gold content, monomers, and BCP architecture. After ligand exchange, network formation, and reprocessing through heat compression, the unique optical properties of Au-NPs are retained, allowing plasmonic heating to trigger the transamination exchange reaction within the materials. As a result, the Au-doped vitrimers can self-heal and exhibit shape-memory shortly after exposure to not only heat but also light. This incorporation of Au-NPs into vitrimers could provide a versatile platform for the development of hybrid materials offering potential applications in coatings, sensors, electronic devices, etc.

Oligomers incorporating styrene chromophores, linked by 1,2-isobutylidene and 2,2-propylidene spacers in various proportions, are synthesized through the NiCl₂(PPh₃)₂-catalyzed olefination-oligomerization of benzene-bisdithioacetal under diverse conditions using excess MeMgI and ZnI₂. The method provides a convenient pathway for selectively synthesizing oligomers with distinct ratios of one-carbon and two-carbon linkers, strategically employed to spatially separate adjacent vinylarene chromophores. The emission profiles for these oligomers span from 380 to 450 nm, in addition to the intrinsic emission of styrene ≈315 nm. The intensity of the blue light emission varies depending on the ratio of the aliphatic linkers, attributed to through-space intrachain ground-state interactions among the styrene chromophores. Consequently, emission properties can be finely tuned; π-conjugated chromophores enriched with 2,2-propylidene linkers display higher luminescence intensity with discernible vibronic structure compared to those with higher percentages of 1,2-isobutylidene spacers. This difference underscores the folding behaviors of the oligomers, where even slight structural variations in the oligomer structure can markedly influence their 3D conformation. Importantly, these experimental findings are corroborated by molecular dynamic simulations.