Chinese Journal of Polymer Science最新文献

As a type of bi-functional device, electrochromic supercapacitors (EC-SCs) have attracted extensive attention in diverse applications such as flexible electronics. However, despite recent encouraging progress, rational design and development of high-performance EC-SC materials with desirable stability remain challenging for practical applications. Here, we propose a fluorination strategy to develop high-performance EC-SC materials with tough hydrogen bonding cross-linked intermolecular polymer network by one-step electrosynthesis of 3-fluorothiophene. The electrosynthesized free-standing poly(3-fluorothiophene) (PFT) films simultaneously achieve high electrochromic performance (optical contrast 42% at 560 nm with reversible color changes between purple and blue), and good capacitance property (290 F·g⁻¹, 1 A·g⁻¹), as well as outstanding cyclic stability (<2% reduction after 20000 cycles). We further demonstrate the fabrication of PFT-based flexible electrochromic supercapacitor devices (FESDs), and the resultant devices can be used to visually monitor the energy storage state in real-time and maintain outstanding stability under mechanical distortion like bending. Such a tough fluorination hydrogen bonding cross-linking strategy may provide a new design concept for high-performance EC-SC materials and reliable FESDs toward practical applications.

This study utilizes molecular dynamics simulation to investigate the complex dynamics of entangled semi-flexible polymer melts. The investigation reveals a significant stress overshoot phenomenon in the systems, demonstrating the intricate interplay between shear rates, chain orientation, and chain stretching dynamics. Additionally, the identification of metastable states, characterized by a dual-plateau phenomenon in the shear stress-strain curve at specific Rouse-Weissenberg number Wi_R, showcases the system’s responsiveness to external perturbations and its transition to stable shear banding states. Moreover, the analysis of flow field deviations uncovers a progression of shear bands with increasing Wi_R, displaying distinct behaviors in the system’s dynamics under different shear rates and chain lengths. These findings challenge established theoretical frameworks and advocate for refined modelling approaches in polymer rheology research.

Polyethyleneimine (PEI), as a widely used polymer material in the field of gene delivery, has been extensively studied for modification and shielding to reduce its cytotoxicity. However, research aimed at preparing degradable PEI is scarce. In this work, the hydrogen peroxide (H₂O₂) oxidation method was used to introduce degradable amide groups in the PEI and a series of oxidized PEI22k (oxPEI22k) with different degrees of oxidation were synthesized by regulating the dosage of H₂O₂. The relationship between the oxidation degree of oxPEI22k and the gene transfection efficiency of oxPEI22k was studied in detail, confirming that the oxPEI22k with oxidation degrees of 16.7% and 28.6% achieved improved transfection efficiency compared to unmodified PEI. These oxPEI22k also proved reduced cytotoxicity and improved degradability. Further, this strategy was extended to the synthesis of low-molecular-weight oxPEI1.8k. The oxPEI1.8k with suitable oxidation degree also achieved improved transfection efficiency and reduced cytotoxicity. In brief, this work provided high-efficiency and low-cytotoxicity degradable gene delivery carriers by regulating the oxidation degree of PEI, which was of great significance for promoting clinical applications of PEI.

Amyloidosis is characterized by the deposition of fibrillar aggregates, with a specific peptide or protein as the primary component, in affected tissues or organs. Excessive proliferation and deposition of amyloid fibrils can cause organismal dysfunction and lethal pathological outcomes associated with amyloidosis. In this study, a nanochaperone (nChap-NA) was developed to inhibit protein misfolding and fibrillation by simulating the function of natural molecular chaperones. The nanochaperone was prepared by self-assembly of two block copolymers PEG-b-PCL and PCL-b-P(NIPAM-co-AANTA), which had a phase-separated surface consisting of hydrophobic PNIPAM microdomains with coordinative NTA(Zn) moieties and hydrophilic PEG chains. The hydrophobic interaction of the PNIPAM microdomain and the coordination of NTA(Zn) synergistically work together to effectively trap the amyloid monomer and block its fibrillation site. Insulin and human islet amyloid polypeptide (hIAPP) were used as model proteins to investigate the nanochaperone’s inhibition of amyloid misfolding and fibrillation. It was proved that the nanochaperone could stabilize the natural conformation of the trapped insulin and hIAPP, and effectively inhibit their fibrillation. In vivo study demonstrated that the nanochaperone could effectively preserve the bioactivity of insulin and reduce the cytotoxicity caused by hIAPP aggregation. This study may provide a promising strategy for the prophylactic treatment of amyloidosis.

Supramolecular polymer networks (SPNs) are celebrated for their dynamic nature, yet they often exhibit inadequate mechanical properties. Thus far, the quest to bolster the mechanical resilience of SPNs while preserving their dynamic character presents a formidable challenge. Herein, we introduce [2]rotaxane into SPN to serve as another cross-link, which could effectively enhance the mechanical robustness of the polymer network without losing the dynamic properties. Compared with SPN, the dually cross-linked network (DPN) demonstrates superior breaking strength, Young’s modulus, puncture force and toughness, underscoring its superior robustness. Furthermore, the cyclic tensile tests reveal that the energy dissipation capacity of DPN rivals, and in some cases surpasses, that of SPN, owing to the efficient energy dissipation pathway facilitated by [2]rotaxane. In addition, benefiting from stable topological structure of [2]rotaxane, DPN exhibits accelerated recovery from deformation, indicating superior elasticity compared to SPN. This strategy elevates the performance of SPNs across multiple metrics, presenting a promising avenue for the development of high-performance dynamic materials.

Thermochromic polymers with tunable thermochromism, high stretchability and mechanical strength are of interests for optical information storage and encryption. In this work, we demonstrate a new design of thermo-fluorochromic carboxylated nitrile butadiene rubber (XNBR) elastomer cross-linked by Eu³⁺-COOH dynamic coordination with deprotonated imidazole (DPIm) as the ancillary ligand. The presence of DPIm not only improves the mechanical strength and stretchability, but also dramatically intensifies the fluorescence emission and lifetime of the Eu-containing elastomer. The elastomer behaves reversible thermo-fluorochromism with easily tunable transition temperature and emission intensity by the simple change of the deprotonation degree of imidazole. The facile tunable thermo-fluorochromism, exceptional mechanical strength, and high stretchability (up to about 5000%) enable the Eu-containing XNBR elastomer with potential applications in soft electronics where optical information storage and encryption are required.

The incorporation of dynamic covalent bonds into thermosets facilitates the reprocessing of polymer networks, thereby meeting the sustainable requirements for polymer recycling. However, the mechanical properties of many materials often decline significantly upon reprocessing due to side reactions caused by harsh processing conditions. In this work, we find that the aromatic dithiocarbamate bond can undergo dissociation under mild conditions without the need for a catalyst, enabling the efficient reprocessing of the corresponding polydithiourethane. As a consequence, the mechanical properties of the polydithiourethane can be largely preserved after reprocessing. The discovery of this dynamic chemistry is anticipated to broaden the potential for material design in dynamic covalent polymer networks.

Titanium dioxide (TiO₂) hollow nanoparticles present significant potential for photocatalytic applications while their straightforward preparation with precise structure control is still challenging. This work reports the approach to preparing tunable hollow TiO₂ nanospheres by utilization of spherical polyelectrolyte brushes (SPB) as nanoreactors and templates. During the preparation, the evolution of the structure was characterized by small angle X-ray scattering (SAXS), and in combination with dynamic light scattering and transmission electron microscopy. The formation of TiO₂ shell within the brush (SPB@TiO₂) is confirmed by the significant increase of the electron density, and its internal structure has been analyzed by fitting SAXS data, which can be influenced by Titanium precursors and ammonia concentration. After calcining SPB@TiO₂ in a muffle furnace, hollow TiO₂ nanospheres are produced, and their transition to the anatase crystal form is triggered, as confirmed by X-ray diffraction analysis. Utilizing the advantages of their hollow structure, these TiO₂ nanospheres exhibit exceptional catalytic degradation efficiency of methylene blue (MB), tetracycline (TC), and 2,4-dichlorophenoxyacetic acid (2,4-D), and also demonstrate excellent recyclability.

Polymer density-functional theories (PDFTs) have distinct advantages in the study of polyelectrolyte (PE) systems over experiments and molecular simulations. Here we give an introductory review of some PDFTs recently developed for PE systems. We start with a general formalism of PDFTs and its relation to the widely used polymer self-consistent field theory (SCFT), then explain the various correlations that are neglected in SCFT but can be accounted for in PDFTs, including those due to the excluded-volume interaction and chain connectivity of uncharged polymers, the electrostatic correlations of small ions, and the chain correlations in PEs. We also list some applications of PDFTs for PE systems, and finally give some perspectives on future work. We hope that our review can attract more researchers to apply and further develop PDFTs as a promising class of theoretical and computational tools.

To realize single-stimulus-induced simultaneous multi-behaviors in hydrogels is still quite challenging nowadays. Herein, an intelligent pH-responsive hydrogel (BP4VA/PAS) with rapid and high contrast changes in color, fluorescence, and shape simultaneously is reported. The BP4VA/PAS hydrogel is fabricated by incorporating styryl anthracene derivative (BP4VA) into copolymer networks (PAS) of acrylamide and sodium 4-styrene sulfonate. Under acid conditions, the protonation of BP4VA generates a rapid change with high color contrast from yellow to red and a fluorescence switch between bright green and weak red emission. At the same time, the electrostatic interactions between 2H-BP4VA²⁺ and sulfonate anions suspended on PAS trigger BP4VA/PAS hydrogels to shrink. Upon alkaline treatment, the 2H-BP4VA²⁺/PAS hydrogel deprotonates and recovers to its original color, fluorescence, and shape. Furthermore, utilizing rapid and remarkable pH-responsive properties of BP4VA/PAS hydrogels, we successfully demonstrated its applications in biomimicry, camouflage, and multistage information encryption. Collectively, this work provided an elegant strategy to develop intelligent hydrogels in applications of biomimetic smart materials and information encryption.