Macromolecular Rapid Communications最新文献

Hexaarylbiimidazole (HABI) molecules have awakened a broad interest in photo-processing, super-resolution imaging, photoinduced self-healing materials, and photomechanical hydrogels due to their excellent photosensitivity and photo-induced cleavage properties. In this work, a novel photoswitchable branched polyurethanes (BPU), which are synthesized by copolymerizing HABI with glycerol, isophorone diisocyanate (IPDI), and polyethylene glycol (PEG₄₀₀), is designed. 7-Diethylamino-4-methylcoumarin (DMCO) is introduced as a radical quencher, which can not only avoid the hydroxyl interfering from conventional radical scavengers during the polymerization process but also promote efficient quenching of TPIR radicals. By optimizing the DMCO concentration, and HABI content, high-quality lithographic patterns are achieved with high film retention at low exposure doses. The branched structure exhibits superior photosensitivity and solubility after exposure compared to previous crosslinked systems. This work provides HABI-based branched polyurethane, which acts as one of the potential candidates for UV-positive photoresists.

Residual dipolar coupling (RDC) not only contributes to the dynamic analysis of proteins but also provides a robust route for the structure determination of small organic compounds. An essential prerequisite for this methodology is the availability of alignment media. Herein, a series of novel peptide-based alignment media are generated by introducing D-type or halogen-bearing amino acids for RDC measurements. Compared with a self-assembled peptide liquid crystal (LC) medium containing _D-amino acid, the incorporation of halogen elements improved the electronegativity of peptide LCs, resulting in enhanced alignment strength toward analytes. Meanwhile, halogen-bearing peptide LCs can provide different orientations relative to non-halogenated peptide media, allowing the acquirement of independent sets of RDCs. The presented peptide LCs not only enrich the existing alignment media but also ignite a way of creating multiple alignment media for independent, non-linearly related sets of RDC measurement.

A series of biomass-based linear aliphatic polyesters are synthesized by combining sebacic acid (SA) (C10 diacid) and 1,18-octadecanedioic acid (OA) (C18 diacid) with a series of diols with varied alkyl chain lengths (C2 to C10 diols). SA and OA are obtainable from castor oil and palm oil, respectively. The reaction extent (polymerization extent) is high (≥96%) in all cases, and the number-average molecular weight (M_n) is 10 000-43 000 g mol^-1 after purification. A possible limitation of currently available biomass-derived polyesters is their relatively low melting temperatures (T_m). The polyesters synthesized using OA with a long alkyl chain (C18 chain) in the present work exhibit relatively high T_m values of 78-93 °C, which are rather close to that (105-118 °C) of low-density polyethylene (LDPE), and may serve as biomass-based alternatives to LDPE with respect to thermal properties. Scientifically notably, an odd-even effect is observed in the T_m values. Polyesters with an even total-number of carbon atoms in the repeating unit have higher T_m values than their odd total-number counterparts likely due to their different orientations of dipoles of the polar ester groups along the backbone chain.

The modification of thermoplastic polymers is frequently impeded by the inherent contradiction between their toughness and strength. In this study, an effective strategy to significantly improve the mechanical properties of ductile polymers by simply adding a complimentary rigid polymer is introduced. This work uses a semi-crystalline polymer aliphatic polyketone (POK) as the matrix material and a small quantity of polymethyl methacrylate (PMMA) as the rigid polymer, through establishing molecular chain entanglements at the interface to produce POK/PMMA blends with exceptional mechanical property. The experimental study shows that PMMA as a small island phase is homogeneously dispersed in the POK matrix, while the interfacial adhesion between the POK matrix and PMMA island is enhanced by the high-density molecular chain entanglement between PMMA and the POK matrix. The strong entanglements and high concentration of PMMA domains promote uniform crazes and overall shear yielding. As a result, the POK/PMMA blend exhibits exceptional mechanical properties with notched impact strength, elongation at break, tensile strength, and Young's modulus, of 20 kJ m^-2, 326%, 60 and 2185 MPa, respectively. A universal approach is further suggested for enhancing the toughness and strength of ductile polymers using a complimentary rigid polymer.

Hydrogels are flexible materials characterized by a 3D network structure, which possess high water content and adjustable physicochemical properties. They have found widespread applications in tissue engineering, electronic skin, drug delivery, flexible sensors, and photothermal therapy. However, hydrogel networks often exhibit swelling behavior in aqueous environments, which can result in structural degradation and a loss of gel performance. In this study, polyacrylic acid is utilized as the primary network structure with the incorporation of the natural polymer chitosan. Furthermore, a conductive hydrogel exhibiting good mechanical strength similar to human skin and excellent anti-swelling properties is developed by integrating phytic acid into the hydrogel network. The as-prepared hydrogels exhibited maximum swelling in pure water, achieving an equilibrium swelling rate of 15%. Additionally, a dopamine-grafted polyacrylic acid binder is synthesized through a coupling reaction to enhance the adhesion of the hydrogels to various substrates. The hydrogels demonstrated strong adhesion properties with different substrates. Whether in the air or underwater, the hydrogel sensor effectively monitors human movement behaviors. Furthermore, by utilizing the sensing signals to send Morse code, the hydrogel sensor can facilitate underwater communication. This type of hydrogel sensor is anticipated to play a significant role in wearable sensing applications and underwater communication.

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.

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.

The self-assembly of macromolecular segments promotes the fabrication of polymer microspheres with multiple morphologies. Inspired by the xanthium shells, A dual-driven self-assembly method have defined that enables the construction of multi-dimensional morphologies on the microsphere surface at emulsion-confined interfaces. The two driving forces are derived from the phase separation caused by the immiscibility of macromolecular segments and the different interactions between chain segments of different hydrophilicity and water molecules. The synergistic effects of these two forces, the xanthium shell structure is constructed on the microsphere surface, enabling the development of increasingly complex superstructure. This scalable approach provides extensive potential for the self-assembly technology of block copolymers with opposite properties.

Myocardial infarction (MI) is a leading cause of mortality among cardiovascular diseases. Following MI, the damaged myocardium is progressively being replaced by fibrous scar tissue, which exhibits poor electrical conductivity, ultimately resulting in arrhythmias and adverse cardiac remodeling. Due to their extracellular matrix-like structure and excellent biocompatibility, hydrogels are emerging as a focal point in cardiac tissue engineering. However, traditional hydrogels lack the necessary conductivity to restore electrical signal transmission in the infarcted regions. Imparting conductivity to hydrogels while also enhancing their adhesive properties enables them to adhere closely to myocardial tissue, establish stable electrical connections, and facilitate synchronized contraction and myocardial tissue repair within the infarcted area. This paper reviews the strategies for constructing conductive and adhesive hydrogels, focusing on their application in MI repair. Furthermore, the challenges and future directions in developing adhesive and conductive hydrogels for MI repair are discussed.

As the demand for clean water intensifies, developing effective methods for removing pollutants from contaminated sources becomes increasingly crucial. This work establishes a method for additive manufacturing of functional polymer sorbents with hollow porous features, designed to enhance interactions with organic micropollutants. Specifically, core-shell filaments are used as the starting materials, which contain polypropylene (PP) as the shell and poly(acrylonitrile-co-butadiene-co-styrene) as the core, to fabricate 3-dimensional (3D) structures on-demand via material extrusion. After 3D printing, the cores of the printed roads are removed through solvent extraction, creating hollow structures that increase accessible surface area for adsorption. Subsequently, a sulfonation-induced crosslinking reaction installs sulfonic acid functionalities into the PP backbones, while enhancing their chemical stability. It is found that larger voids, and thinner polymer shells, enable improved structural retention during the sulfonation through limiting reaction-induced stresses. The hollow sulfonated PP sorbents exhibit a strong affinity against cationic pollutants. Specifically, larger voids within these structures not only improve structural integrity but also result in accelerated adsorption kinetics by maximizing accessible surface area, thereby enhancing pollutant removal efficiency. This work provides a promising solution for advanced structured sorbent fabrication with hollow architectures, leading to more effective solutions for water contaminant removal in the future.