Macromolecular Rapid Communications最新文献

Enzymes are essential biological catalysts, which have merits such as specificity, high efficiency, and mild-acting conditions. Due to the characteristics of enzymes, problems such as poor operational stability and difficulty in reuse limit the practical application of enzymes. These problems can often be solved by immobilization of enzymes. Commonly used enzyme immobilization materials include biochar, chitosan, polymer, and metal-organic frameworks, which often do not match the nature of the enzyme. This study utilizes the self-assembled amino acid hydrogel Fmoc-Y-OMe as the immobilizing material. The hydrogelator Fomc-Y-OMe has advantages like simple synthesis, easy immobilization, environmental friendliness, and good compatibility with proteins. It is able to protect enzyme activity at high temperatures and under a wide range of acid-base conditions and has excellent versatility. In particular, immobilized polyethylene terephthalate degrading enzyme (PETase) can significantly degrade polyethylene terephthalate (PET) film at 70 °C, while free PETase completely loses its catalytic capacity at such high temperatures. The excellent performance of self-assembled hydrogels to protect the catalytic activity of enzymes at high temperatures is highlighted.

Covalent organic framework (COF)-derived carbon materials seamlessly inherit the periodic porous architecture and high specific surface area of their precursors, while simultaneously enabling the confinement of nanoparticles in designated regions. This unique feature mitigates agglomeration, enhances intrinsic properties, and imparts novel functionalities to the resulting materials. Consequently, COF-derived carbon materials have garnered significant attention across diverse fields, including energy, environmental remediation, and biomedical applications. Despite this burgeoning interest, a comprehensive review encompassing the synthesis, classification, and multifaceted applications of these materials remains scarce. In this context, the state-of-the-art advancements in COF-derived carbon materials are reviewed systematically here. It categorizes the materials, delineates their primary synthesis strategies, and highlights their versatile applications in catalysis, electrochemical energy storage, water treatment, sensing, and cancer therapy. Lastly, fresh insights into the challenges and future prospects of COF-derived carbon materials, paving the way for their expanded exploration and utilization are offered here.

Bond-exchangeable cross-linked materials, including covalent adaptable networks and vitrimers, exhibit numerous advantageous properties such as reprocessability, recyclability, and healability. These features arise from the relaxation and diffusion of network polymers facilitated by bond exchange within the network. The application of these materials in functional adhesives is particularly promising, given the growing demand across various industries. It is well established that vitrimer films can adhere to a wide range of substrates. In this study, a novel concept of bond exchange-based adhesion between different polymers is introduced, specifically noting that each polymer does not inherently possess bond-exchange capabilities. The key feature lies in activating bond exchange exclusively at the interphase. Significant adhesion between commercial thermoplastic polyurethanes and cross-linked poly(acrylate)s with hydroxy side groups randomly is demonstrated, achieved through transcarbomoylation bond exchange at the contact interphase. The incorporation of a small amount of bond exchange catalyst is crucial for enhancing adhesion, and both adhesion strength and fracture behavior can be manipulated through specific heating conditions. Overall, this study explores a new functionalization approach using the bond exchange concept, contributing to the development of a practical adhesion technique that eliminates the need for traditional adhesives.

Hydrophobic porous materials are of significant interest due to their potential for various large-scale industrial applications. In this study, we introduce the synthesis of a hydrophobic fluorine-containing covalent organic framework (F-COF), TAPB-TFA, using a low-temperature method, along with its applications in liquid marbles and oil/water separation. By a scandium(III) trifluoromethanesulfonate-catalyzed Schiff-base reaction, uniform spherical TAPB-TFA particles at the nanoscale are successfully synthesized. Results show that TAPB-TFA exhibits high crystallinity, excellent thermal and chemical stability, as well as superoleophilic/hydrophobic properties. The hydrophobic TAPB-TFA particles can be utilized to create various liquid marbles that exhibit excellent shape reconfigurability. Experiments confirm the outstanding performance of TAPB-TFA in separating oil/water mixtures and water-in-oil emulsions, achieving a separation efficiency of over 98.5%. The analysis concludes that the exceptional separation performance of TAPB-TFA is attributed to the synergistic effects of surface wetting-induced aggregation and size-sieving. TAPB-TFA demonstrates significant potential for applications in the environmental and energy sectors.

Preparation of irreversible sp² carbon-conjugated covalent organic frameworks (sp²c-COFs) with specific porosity, easy structural functionalization, high chemical stability, and unique π-electron conjugation structure (especially the combination of π-π stacking interactions and conjugation system), can remove the barrier of electron transfer and provide a unique advantage for photocatalytic water splitting. Herein, based on three kinds of reactions (Aldol condensation reaction, Knoevenagel condensation reaction, and Horner-Wadsworth-Emmons reaction) and guided by the precise modulation of ligand structure and topology, this review summarizes the synthesis of sp²c-COFs and their applications in photoelectrocatalytic water splitting (hydrogen evolution and oxygen evolution reactions). Furthermore, challenges and possible research directions for sp²c-COFs in photocatalytic water splitting are also provided.

The need for functional polymers derived from plant-based materials has increased from a carbon-neutral perspective. Herein, six different semialicyclic isosorbide-containing diamine-based polyimides (ISSD-PIs) are synthesized by incorporating isosorbide (ISS), which is a D-glucose derivative, into the diamine moiety to investigate the relationship between the chemical structure and optical, thermal, and dielectric properties. Compared with the conventional fully aromatic PIs, such as Kapton, the as-prepared ISSD-PIs demonstrate excellent optical transparency, low refractive indices (1.554-1.633), low birefringence (0.0084-0.0348) at 1310 nm, and low dielectric constants (2.93-3.36) with moderate dissipation factors (0.0112-0.0267) at 10 GHz. They also exhibit excellent thermal stability, with glass transition temperatures exceeding 250 °C and 5% thermal decomposition temperatures exceeding 400 °C. The chirality of the ISS skeleton remains intact, displaying characteristic circular dichroism. This study shows that the incorporation of ISS into PI chains enhances their optical and dielectric properties while maintaining thermal stability by increasing the free volume and reducing intermolecular interactions. In addition, the physical properties of the ISSD-PIs are more dependent on the rigidity of the dianhydride moiety, which directly affects the molecular packing of the PI chains, rather than that of the diamine moiety.

A microwave-assisted dual-crosslinked seed emulsion polymerization method is reported to prepare anisotropic trimeric poly(ionic liquid) (PIL) microspheres. First, ethylene glycol dimethacrylate (EGDMA)-crosslinked PIL (CPIL) seed microspheres are prepared. Then, the CPIL microspheres are swollen with ionic liquid (IL) emulsion containing divinylbenzene (DVB) and polymerized to form dual-crosslinked PIL (D-CPIL) microspheres under microwave irradiation. Finally, the D-CPIL microspheres are swollen with IL monomer emulsion to form trimeric morphology and polymerized to obtain trimeric PIL microspheres under microwave irradiation. The formation process of trimeric PIL microspheres is tracked using an optical microscope and their morphology is observed using scanning electron microscopy. Different from the repeat-swelling seed emulsion polymerization that needs dumbbell-like seed microspheres having gradient crosslinking or gradient surface wettability, this method depends on multiple local contraction forces in D-CPIL microspheres containing lowly crosslinked core and highlycrosslinked shell during swelling to form trimeric PIL microspheres. It is found that microwave polymerization is important because it can well retain trimeric morphology compared to conventional heating polymerization in oil or water baths. The morphology of trimeric PIL microspheres can be adjusted by changing the type and amount of crosslinkers, monomer/seed microsphere ratio, initiator dosage, temperature, etc.

Molecular weight is a crucial characteristic of polymers which has a great influence on various polymer properties. Controlling molecular weight is a key aim in polymer research. Traditionally, chemical synthesis as a "bottom-up" approach is the most common method to tune polymer molecular weight. Alternatively, breaking polymer chains by mechanical forces (e.g., ultrasound, ball-mill grinding, and flow) is another pathway to adjust the molecular weight distribution. Herein, a new "top-down" approach employing ultramicrotome to cut the polymer chains to manipulate the polymer molecular weight is reported. By controlling the slice thickness and polymer swelling conditions, and the initial high molecular weight polymer chains can be cropped into fragment chains with designed molecular weight in a well-defined way. This work presents a new strategy to manipulate polymer molecular weight and will also provide a unique platform for further study of polymer mechanochemistry.

Spatial control over supramolecular self-assembly prevails in living system, yet remains difficult to replicate in synthetic scenarios. Here, on the basis of a hydrazone formation-mediated supramolecular hydrogelation system, access to patterning of supramolecular hydrogels is demonstrated via a light-triggered catalysis strategy. A photoacid generator that can produce protons in aqueous solutions upon irradiation is employed. The generated protons lead to a drop in pH of around three units (initial pH 7.0), effectively accelerating the formation and self-assembly of the hydrazone gelators. Because of the light-triggered catalysis, the hydrogelation samples in the presence of photoacid generator show lower critical gelation concentration, higher stiffness, and denser networks. Importantly, by performing selective irradiation using differently shaped masks, various spatially resolved supramolecular hydrogels following the shapes of the masks are fabricated. The concept of using light-triggered catalysis to realize spatial control over supramolecular self-assembly provides an alternative approach toward bottom-up fabrication of structured soft materials for various applications such as tissue engineering, single cell manipulation, and biosensing.

The all-solid-state single ion conducting polymer electrolyte has a bottleneck in ionic conductivity even though it can prevent concentration polarization. Here, lithium 3,3'-(diallylammonio)bis(propane-1-sulfonyl(trifluoromethyl sulfonyl)imide) (LiDAA(PSI)₂) with a symmetrical "one positive, two negative" structure and unsaturated double bonds for propagation, is synthesized. LiDAA(PSI)₂ is copolymerized with 1,2-ethanedithiol and poly(ethylene glycol) diacrylate via photoinitiated thiol-ene click polymerization and forms a random copolymer, SPZ for short. For comparison, lithium 3-(diallylamino)propane-1-sulfonyl(trifluoromethyl sulfonyl)imide) (LiDAAPSI) and corresponding copolymer SP are synthesized. The ⁷Li resonance peak position of LiDAA(PSI)₂ shifts to a low-field compared to that of LiDAAPSI, indicating a weaker electrostatic attraction. The symmetrical "one positive, two negative" structure is responsible for the low-field shift, taking effect of charge conjugation. Unsurprisingly, the ionic conductivity of SPZ is 1.69e-5 S cm^-1 at 60 °C, which is 1.9 times that of SP. Lithium electroplating and stripping at 0.0125 mA cm^-2@0.05 mAh cm^-2 at 60 °C are performed. An all-solid-state single ion conducting lithium metal secondary battery is demonstrated. Zwitterion coupled LiDAA(PSI)₂ possesses a symmetrical "one positive, two negative" structure, charge conjugation to weaken electrostatic interaction, and unsaturated double bonds for propagation, which inspires the design and synthesis of single ion conducting polymer electrolytes with zwitterion effect.