Macromolecular Rapid Communications最新文献

Silicone rubber (SiR) has a wide range of medical applications, but it lacks antimicrobial properties, leading to potential infection issues with related implants or medical devices. Most studies focus on adding anti-bacterial agents or surface modification, which usually result in composites with anti-bacterial properties, rather than synthesizing SiR with intrinsically antimicrobial performances. To tackle this issue, a double substituted bornyl-siloxane crosslinker (BC) is designed. This crosslinker can react with hydroxy-terminated polydimethylsiloxane (PDMS) at room temperature to yield SiR with borneol side groups. The process is simple without using additional solvents. Antimicrobial assay on SiR cured with different ratios of BC/PDMS showed that 20 wt.% BC cross-linked network exhibited outstanding anti-bacterial adhesion (Escherichia coli 99.4%, Staphylococcus aureus 97.3%) performance and long-lasting anti-mold (Aspergillus niger over 99% for 30 days) adhesion properties. Moreover, the subcutaneous implantation model in mice demonstrated its excellent anti-infection, biocompatibility and safety. Therefore, this material is promising for widespread adoption in the medical field, especially in silicon-based products or coatings.

Recent advancements in inverse vulcanization have led to the development of sulfur-rich polymers with diverse applications. However, progress is constrained by the harsh high-temperature reaction conditions, limited applicability, and the generation of hazardous H₂S gas. This study presents an induced IV method utilizing selenium octanoic acid, yielding sulfur-selenium rich polymers with full atom economy, even at a low-temperatures of 100-120 °C. The resultant sulfur-selenium rich polymers exhibit exceptional optical properties: 1) A high refractive index, reaching 1.89 when the total sulfur-selenium content is 65%; 2) Excellent UV shielding capabilities, blocking ultraviolet rays while permitting 95.1-98.6% transmission of visible light; 3) Notable transparency, with polymer films of 0.94 mm thickness exhibiting good transparency under natural light. The materials also demonstrate environmental stability under prolonged exposure to hot or cold conditions. Additionally, the polymers display adhesive strength as evidenced by two adhered glass slides with the material lifting weights of up to 20 kg without any displacement in their glued area. These properties provide a new avenue for sulfur-selenium rich materials to be implemented in high-precision optical instruments with unique characteristics.

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.

Polymers of intrinsic microporosity (PIMs) are an emerging class of amorphous organic porous materials with solution processability, which are widely used in a multitude of fields such as gas separation, ion conduction, nanofiltration, etc. PIMs have adjustable pore structure and functional pore wall, so it can achieve selective sieving for specific substances. In order to meet the functional requirements of PIMs, two principal methods are used to synthesize functional PIMs, namely, post-modification of PIMs precursors and functionalization of monomers. A number of post-modification routes have been reported, however, the direct synthesis of functional PIMs with diverse groups still remains a challenge. The synthesis of PIMs through the acid-catalyzed polyhydroxyalkylation has been demonstrated to be an effective solution, exhibiting the advantages of wider substrates range, milder reaction conditions, and higher molecular weight. Recently, a series of functional substrates for direct synthesis of PIMs have been proposed. This article presents a review and summary of recent advances in synthesizing PIMs via acid-catalyzed polyhydroxyalkylation, and the synthesis route and structure-activity relationship are emphasized, which provides a versatile platform for the direct synthesis of functional PIMs.

Novel amphiphilic π-conjugated polymer nanoparticles tailored to efficiently absorb in the near-infrared II (NIR-II) region of the electromagnetic spectrum (>1000 nm) are presented. To achieve this, it is statistically introduced triethylene glycol substituted bithiophene moieties in various contents into a polymer backbone consisting of alternating thiophene and [1,2,5]thiadiazolo[3,4-g]quinoxaline. Through systematic modifications of monomer ratios, four amphiphilic conjugated polymers are produced. The presence of hydrophilic side chain, like triethylene glycol monomethyl ether, enhanced the polymer's concentration in aqueous media of up to 470%, versus the D-A thiophene and [1,2,5]thiadiazolo[3,4-g]quinoxaline hydrophobic analog polymer, enabling the production of surfactant-free conjugated polymer nanoparticles (CPNs) with higher concentrations (20.3 ppm maximum). Subsequently, the impact of this structural fine-tuning on the optical properties of the polymers and their corresponding CPNs are meticulous investigated. In both cases, it is identified the minimum bithiophene content that maintained the absorption spectra above 1000 nm at significantly higher concentrations. So, these findings contribute to the extensive prospects of these materials in multiple fields including biomedical and optoelectronic applications.

Simultaneous improvement in power conversion efficiency (PCE) and device stability is very important for organic solar cells (OSCs). Herein, oligothiophene-based polymer W19 with excellent solvent resistance is exploited as a polymer thin layer to optimize the active layer morphology and then device efficiency and stability. Polymer W19 possesses a simple skeleton of trifluromethyl-substituted dithienoquinoxaline and quaterthiophene, whose thin layer shows suitable energy level, low surface energy, and strong interchain aggregation, leading to outstanding solvent resistance and excellent hole transport ability. Optimized vertical separation alleviates trap state density and energy loss, improves hole transfer dynamics, and balances the charge transport, thus maximizing open-circuit voltage, short-circuit current density, and fill factor simultaneously. A high PCE of 19.70% is achieved for the W19 treated devices. Noticeably, OSCs treated with W19 retained 87% of its initial PCE after continuous illumination for 800 h, which is higher than that of 74% of the control. Large area devices of 1 and 4 cm² can achieve high efficiencies of 17.36% and 14.46%, respectively. This work highlights that the polymer thin layer W19 with the ability of strong solvent resistance has the great potential to further improve the efficiency and photostability of OSCs.

Cephalopods such as squids, octopuses, and cuttlefishes can change their bodies' color to match the surrounding environments by contracting or expanding the sac just below the surface of the skin. Inspired by this mechanism, artificial cephalopod chromatophores which are prepared by thermoresponsive poly(N-isopropyl acrylamide)-based hydrogel films embedded with black, red, and yellow pigments are presented, they can swell and shrink under temperature stimuli, like the natural chromatophores. The artificial chromatophores embedded with cuttlefish ink are further used to fabricate artificial J.heathi octopus skin by sandwiched between a transparent outer layer and a transparency-switchable substrate, thus camouflage skin can be achieved by controlling temperature or NIR irradiation. The artificial chromatophores with red and yellow pigments are further incorporated with the colloidal photonic crystals patches which are embedded in a white substrate, and the iridescence patches keep disappearing-reappearing with the expanding-contracting behavior of the pigment-containing chromatophores, like the skin of squids. These bioinspired artificial skins with the excellent capability of dynamic camouflage have potential applications for color displaying, camouflage, and smart wearable devices.

Utilization of reusable catalysts and reaction media has recently been an area of interest to devise a sustainable approach. Interestingly, photoinduced reversible deactivation radical polymerization (photoRDRP) of glycidyl methacrylate (GMA) is achieved with reusable and magnetically separable nano zero-valent Iron (nZVI). This resulted in well-defined poly(glycidyl methacrylate) (PGMA) (upto 22700 g mol^-1) with a low dispersity (Đ ≤ 1.20). Using an ionic liquid and a straightforward low-cost technique, three different copolymers: poly(glycidyl methacrylate-random-dimethyl amino ethyl methacrylate) poly(GMA-r-DMAEMA), poly(glycidyl methacrylate-random-methyl methacrylate) poly(GMA-r-MMA) and poly(glycidyl methacrylate-random-styrene) poly(GMA-r-St) are produced, all without the need for traditional photoinitiators. The response of the poly(GMA-r-DMAEMA) to pH variations is evaluated.

Metal ions, which are naturally occurring in food, soil, and water, are present in every part of the environment. Therefore, it is imperative to identify those using accessible and economical methods. In this study, a novel two-step chemical modification process for pullulan, a natural polymer, is presented. This process yields a macromolecular derivative with considerably increased fluorescence, enabling efficient detection of specific metal ions. Furthermore, the recently synthesized polymer displays distinctly divergent characteristics in comparison with the native pullulan, a consequence of the undergone chemical reactions. These include the existence of fluorescence and solubility in organic solvents, which are lacking from the initial polymer. Subsequent to exhaustive thermal and spectral analysis, the synthesized polymer's capacity to discern disparate metal ions is investigated. The interaction between metal ions and the pullulan derivative is monitored to ascertain the extent of fluorescence quenching during this process. The synthesized polymer exhibits the greatest sensitivity to Fe³⁺ and Cu²⁺ among the various cations that are examined, while Pb²⁺ and the other ions demonstrate satisfactory results. The paper also discusses the underlying quenching mechanism and possible future applications.

Intrinsically conductive polymers have garnered a great deal of attention for use in medical and bioelectronic applications. Despite this, challenges associated with the mechanical stability, processability, and fabrication of conducting polymers have limited their utility. To circumvent these limitations, thiophene substituted 2-oxazolines (2Ox) and 2-oxazines (2Ozi) are introduced, which can be polymerized to form a thermally stable and potentially melt-processable polymers as precursors for conductive polymers. A series of such monomers are synthesized and yields above 50% are obtained for gram scale reactions. The monomers can subsequently be polymerized using standard cationic ring-opening methods to yield thiophene-bearing poly(2-oxazoline)s (POx) and poly(2-oxazine)s (POzi) with narrow to moderate dispersity. The polymers exhibit glass transition temperatures between 50 °C and 100 °C and thermal stability beyond 250 °C. Moreover, random copolymers can be produced by introducing aliphatic 2-oxazolines during polymer synthesis, which facilitates tailoring of the polymer properties and may enable new applications in melt extrusion printing or electrospinning of precursors for conducting polymer systems. Overall, a facile approach is described for the synthesis of thiophene-functionalized monomers and polymers, providing covalent integration of thiophenes that opens new avenues toward the generation of functional and stimuli-responsive biomaterials.