Chinese Journal of Polymer Science最新文献

Knots are discovered in a wide range of systems, from DNA and proteins to catheters and umbilical cords, and have thus attracted much attention from physicists and biophysicists. Langevin dynamics simulations were performed to study the knotting properties of coarsegrained knotted circular semiflexible polyelectrolyte (PE) in solutions of different concentrations of trivalent salt. We find that the length and position of the knotted region can be controlled by tuning the bending rigidity b of the PE and the salt concentration C_S. We find that the knot length varies nonmonotonically with b in the presence of salt, and the knot localizes and is the tightest at b=5. As b>5, the knot swells with b increase. In addition, similar modulations of the knot size and position can be achieved by varying the salt concentration C_S. The knot length varies nonmonotonically with C_S for b>0. The knot localizes and becomes tightest at C_S=1.5×10⁻⁴ mol/L in the range of C_S≤1.5×10⁻⁴ mol/L. As C_S>1.5×10⁻⁴ mol/L, the knot of the circular semiflexible PE swells at the expense of the overall size of the PE. Our results lay the foundation for achieving broader and more precise external adjustability of knotted PE size and knot length.

Poly(vinyl alcohol) (PVA) hydrogels have garnered significant attention for tissue engineering, wound dressing, and electronic skin sensing applications. However, their poor mechanical performance severely restricts their multifunctional application in many scenarios. To address this limitation, PVA/tannic acid (TA)@carbon nanotubes (PVA/TA@CNTs) composite hydrogels with triple crosslinking networks were prepared through freezing-thawing and the solvent-induced shrinkage method, utilizing tannic acid-carbon nanotubes (TA@CNTs) as reinforcing units and a Ca²⁺ crosslinking strategy. The enhanced interfacial networks consisting of PVA crystalline domains, hydrogen bonding, and metal co-ordination endowed the composite hydrogel with a high mechanical strength, excellent flexibility, and fracture toughness, accompanied by a significant increase in crystallinity. The tensile strength and fracture toughness of the composite hydrogel reached up to about 7.0 MPa and 17.0 MJ/m³, which were roughly 8 and 10 times higher than neat PVA hydrogel, respectively. The composite hydrogel demonstrated good cytocompatibility, significantly addressing the challenge of balancing structural reinforcement with biosafety in hydrogels. This methodology establishes a rational design for fabricating mechanically robust yet tough PVA hydrogels for biomedical applications.

Effective antifouling coatings are critical for protecting marine infrastructure from biofouling and environmental degradation; however, achieving long-term antifouling performance along with environmental stability remains a major challenge. In this study, a multifunctional bio-based epoxy coating is developed by integrating a dual-action antifouling system. Cinnamic acid (CA), which is known for its antibacterial and UV-shielding properties, was chemically grafted into ethylene glycol diglycidyl ether (EGDE) to provide intrinsic antifouling and anti-UV functions. Simultaneously, the KH560-modified silica aerogel was incorporated to create a dense hydrophobic surface that repels microorganism adhesion. The resulting coating exhibited a superhydrophobic contact angle of 154.3°, an ultralow surface energy, and exceptional resistance to protein and algal adhesion. Additionally, it achieves 99% bactericidal efficiency against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) while maintaining high transparency and ease of processing. These results highlight a promising strategy for designing durable and ecofriendly antifouling coatings suitable for demanding marine environments.

Polybutene-1 (PB-1) is a semi-crystalline polymer with excellent mechanical properties. However, its practical application is significantly hindered by the slow Form II-I transition, which can take up to several days to complete. While prior research established that long-chain branching (LCB) structures synthesized via ω-alkenylmethyldichlorosilane copolymerization-hydrolysis (ACH) chemistry markedly accelerate this transition, this work demonstrates that H-shaped LCB structures constructed through copolymerization with 1,9-decadiene exhibit the capability to facilitate Form II-I transition in most systems evaluated herein. However, low branching efficiency concurrently generates extended alkyl pendant chains, which impose pronounced steric-hindrance-driven suppression on the transition kinetics, thereby substantially diminishing the net acceleration effect of the LCB structures, even resulting in a net retardation effect in certain systems. Notably, a significant synergistic acceleration effect emerged between the H-shaped LCB structures and propylene comonomer units. These findings confirm that the H-shaped LCB structures play a role in promoting the Form II-I transformation process, which is independent of the synthetic pathways, thereby providing more strategies for addressing the long-standing processing problems of PB-1.

Two- and three-component deep eutectic solvents (DES) based on acrylic acid (AA), acrylamide (AAm), and choline chloride (ChCl) were used to disintegrate bacterial cellulose into cellulose nanofibers (CNF). As a result, polymerizable precursors suitable for 3D printing with CNF as a rheology modifier and reinforcer with formation of interpenetrating double polymer network were obtained after UV curing. Composite hydrogels were formed by replacing ChCl with water. It was found that the introduction of amide groups into the acrylate polymer matrix resulted in an increase in compressive strength. The layered architecture of the 3D printed products provides greater mechanical strength compared to molded products. The structure of the composites was investigated using wide-angle X-ray scattering (WAXS), small-angle X-ray scattering (SAXS), atomic force microscopy (AFM) and polarized light microscopy. These studies suggest that the enhanced mechanical properties of the 3D printed hydrogels are associated with swelling and branching of CNF in the DES, as well as alignment of the filler during extrusion. For comparative analysis, composite hydrogels were also prepared using aqueous solutions of AA and AA/AAm with dispersed CNF. However, the 3D printing process was hampered in this case due to cellulose agglomeration. Mechanical testing revealed the formation of premature microcracks in these samples, which were not observed in composites produced using DES. Cytotoxicity of the composite hydrogels was also tested. The results provide valuable insights into the production of strong (up to 3.4 MPa) homogeneous composite hydrogels using 3D printing with nanocellulose filler.

In recent years, flexible ionic conductors have made remarkable progress in the fields of energy storage devices and flexible sensors. However, most of these materials still face challenges such as the difficult trade-off between stretchability and high mechanical strength, as well as insufficient ionic conductivity. Among them, polymerizable deep eutectic solvents (PDES), which possess both hydrogen bond network construction capabilities and ionic conduction properties, have demonstrated great advantages in the synthesis of flexible ionic conductors. Herein, we report an ionic conductive elastomer (ICE) named PCHS-X based on PDES composed of 2-(methacryloyloxy)-N,N,N-trimethylammonium methyl sulfate (MA-MS), choline chloride (ChCl), and 2-hydroxyethyl acrylate (HEA). The introduction of MA-MS enabled the polymer network to form abundant hydrogen bonds, endowing PCHS-X with excellent mechanical strength, high transparency, favorable ionic conductivity, self-adhesiveness, and self-healing efficiency. When used as a strain sensor, the PCHS-X exhibits highly sensitive strain response, along with good stability and durability, allowing it to accurately monitor the movement of human body parts such as fingers, wrists, elbows, and knees. Additionally, owing to the enhanced ionic mobility at higher temperatures, this material also possesses excellent temperature sensing performance, enabling the fabrication of simple temperature sensors that can sensitively respond to temperature changes. This research provides new strategies for the practical applications of flexible electronic devices in fields such as wearable health monitoring and intelligent human-machine interaction.

Colloidal molecules exhibit unique electronic, optical, and magnetic properties owing to their molecular-like configurations and coupling effects, making them promising building blocks for multifunctional materials. However, achieving precise and controllable assembly of isotropic nanoparticles with high yields remains a great challenge. In this study, we present a synergistic strategy that integrates molecular dynamics simulations with interpretable machine learning to develop a programmable assembly system based on block copolymers and DNA-functionalized nanoparticles. Our simulation results reveal that block copolymer modification facilitates stepwise control over surface phase separation and nanoparticle coassembly, thereby enhancing structural stability and efficiently suppressing disordered aggregation of atom-like nanoparticles. Furthermore, we demonstrated that precise, controllable, and programmable assembly of colloidal molecules can be achieved through rational DNA sequence design. SHapley Additive exPlanations (SHAP) analysis identified key structural descriptors that govern assembly outcomes and elucidated their underlying mechanistic roles. This work not only deepens the understanding of colloidal molecule assembly mechanisms but also lays a theoretical foundation for the rational design of functional colloidal architectures in nanomaterial science.

Bacterial infections are becoming the second most common cause of death globally and have contributed significantly to morbidity and mortality. Cationic antibacterial polymers containing quaternary ammonium salts have been explored; however, it remains a key scientific challenge for current research to synergistically optimize the conformational relationships between structural surface features, active sites, and properties. In this study, a novel cationic copolymer microsphere with nano-multiple humps (CPMs-nMHs) was constructed through emulsion polymerization and self-assembly in EtOH/H₂O, with 3-methacrylamido-N,N,N-trimethylpropan-1-aminium chloride (MPAC) as the protruding functional component. Meanwhile, different hydrophilic monomers were adjusted to synthesize polymers with varying forms, which offered a significant research foundation for delving deeper into the impact of their morphology on performance. After being characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), dynamic light scattering (DLS), and thermogravimetric analysis (TG), the obtained CPMs-nMHs were applied to antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Surprisingly, the synthesized CPMs-nMHs exhibited excellent antibacterial performance, discovering that the antibacterial rates of up to 100%, while the activities of contrast copolymers were low. We considered that the dual cooperation of cationic structures and nano-multiple humps were responsible for the antibacterial capabilities. Taken together, cationic copolymer microspheres with nano-multiple humps provide a promising strategy for enhancing the antibacterial properties of cationic polymers.

The introduction of dynamic covalent bonds into the structure of epoxy resins can improve the degradation performance of the materials. But to a certain extent, it will affect the insulating properties of the resin, and how to balance the insulating properties and degradation performance has become an urgent problem. In this paper, the effects of different catalysts on the thermal-force-electrical properties of sorbitol-based resins were systematically investigated based on the dynamic ester bonding to construct the resin crosslinking network, and the biobased sorbitol glycidyl ether was used as the resin matrix. The experiments show that the resin system catalyzed by triethanolamine (TEOA) exhibits excellent comprehensive performance, which combines good thermal stability and mechanical properties with excellent electrical properties (breakdown field strength of 44.21 kV/mm and dielectric loss factor of 0.29%). In addition, chemical degradation tests were conducted on the resin systems with different catalysts, and the experiments showed that the produced resins could be degraded in benzyl alcohol and exhibited good degradation performance. This study provides a theoretical basis and technical path for the development of new bio-based electrical insulating materials with both high insulation and degradation properties, which is conducive to the popularization and application of bio-based resins in the field of electrical equipment.