Strong polyelectrolyte brushes (SPBs) play an important role in enabling material surface functionalization due to their unique stimuli-responsive properties. Although the unexpected pH responsiveness of SPBs has been revealed in the past ten years, it is still unclear if the pH-responsive properties of SPBs are affected by the brush thickness. In this study, we employed the positively charged poly[2-(methacryloyloxy)ethyl] trimethylammonium chloride (PMETAC) and negatively charged sodium poly(styrenesulfonate) (NaPSS) brushes as model systems to explore the effect of thickness on the pH-responsive properties of SPBs. The results demonstrate that the pH-responsive properties of SPBs manifest different dependences on the brush thickness. Specifically, for both PMETAC and NaPSS brushes, the pH-responsive hydration and stiffness are influenced by the thickness, and the pH-responsive wettability and adhesion are almost unaffected by the thickness. This work not only provides a clear understanding of the relationship between the brush thickness and the pH responsiveness of SPBs, but also offers a new method to control the pH-responsive properties of SPBs.

Thermophilic proteins maintain their structure and function at high temperatures, making them widely useful in industrial applications. Due to the complexity of experimental measurements, predicting the melting temperature (T_m) of proteins has become a research hotspot. Previous methods rely on amino acid composition, physicochemical properties of proteins, and the optimal growth temperature (OGT) of hosts for T_m prediction. However, their performance in predicting T_m values for thermophilic proteins (T_m>60 °C) are generally unsatisfactory due to data scarcity. Herein, we introduce TmPred, a T_m prediction model for thermophilic proteins, that combines protein language model, graph convolutional network and Graphormer module. For performance evaluation, TmPred achieves a root mean square error (RMSE) of 5.48 °C, a pearson correlation coefficient (P) of 0.784, and a coefficient of determination (R²) of 0.613, representing improvements of 19%, 15%, and 32%, respectively, compared to the state-of-the-art predictive models like DeepTM. Furthermore, TmPred demonstrated strong generalization capability on independent blind test datasets. Overall, TmPred provides an effective tool for the mining and modification of thermophilic proteins by leveraging deep learning.

Polymers often exhibit multi-state conformational transitions with multiple pathways as temperature varies. However, characterizing the inherent features of these pathways is hindered by the lack of physical characterizations that can distinguish various transition pathways between complex and disordered states. In this work, we introduced a machine-learning framework based on spatiotemporal point-cloud neural networks to identify and analyze conformational transition pathways in polymer chains. As a case study, we applied this framework to the temperature-induced unfolding of a single semi-flexible polymer chain, simulated via coarse-grained molecular dynamics. We first combined spatiotemporal point cloud neural networks and contrastive learning to extract features of conformational evolution, and then we employed unsupervised learning methods to cluster distinct transition pathways and unfolding trajectories. Our results reveal that, with increasing temperature, semi-flexible polymer chains exhibit five distinct unfolding pathways: rigid rod $ \to $ random coil; small toroid $ \to $ large toroid $ \to $ hairpin $ \to $ random coil; rod bundle $ \to $ hairpin $ \to $ random coil; hairpin $ \to $ random coil; and tailed structure $ \to $ random coil. We further calculated the structural order parameters of those typical conformations with distinct transition pathways, we distincted five transition mechanisms, including the straightening of rigid rods, tightening of small rings, expansion of hairpin ends, symmetrization of rod bundles, and retraction of tailed structures. These findings demonstrate that our framework presents a promising data-driven approach for analyzing complex conformational transitions in disordered polymers, which might be potentially extendable to other heterogeneous systems like intrinsically disordered proteins.

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.

An efficient, simple, and convenient method for Suzuki polycondensation using a diaminocarbene palladium(II) catalyst under aerobic conditions was developed. Reactions between aromatic diboronic acid bis(pinacol) ester and different aromatic dibromides, both with electron-donating and electron-withdrawing fragments in the structure, were carried out. Various reaction conditions, such as the effect of catalyst concentration and solvent, were investigated. The molecular weight characteristics, photo- and electroluminescence properties of the synthesized polymers were studied.

The low-voltage plateau capacity, which is highly related to the internal closed pores in hard carbon (HC), is the main contributor to the total capacity in sodium-ion batteries. However, the formation mechanism of closed pores and modification strategies at the molecular level in HC polymer precursors remain poorly understood. Furthermore, the practical applications of HCs are significantly impeded by their low initial coulombic efficiency (ICE). In this study, the intramolecular heteroatom doping (IHP) effect was proposed to facilitate the formation of closed pores in polymer-derived HC for the first time by grafting sulfonyl, ether, and carbonyl groups between benzene rings. As a result, the optimized HC sample showed an increased closed pore volume and low Na⁺ adsorption energy, which delivered a reversible capacity of 307.9 mAh·g⁻¹ and superior rate capability. Through further optimized presodiation, the formed presodiated HC featuring a thin, smooth, and dense solid electrolyte interface film exhibited a remarkably enhanced ICE of 94.4% and enhanced cycling stability (93.6% over 3000 cycles). This study provides an in-depth understanding of the formation mechanisms of closed pores via IHP engineering and develops a new synergistic strategy involving presodiation to prepare highly stable HC anodes.

Poly(vinyl chloride) (PVC) materials are produced with high smoke and toxic gases during combustion, when commercial flame-retardant additives are incorporated. Here, rare-earth yttrium stannate (Y₂Sn₂O₇), which is superior to commercial flame retardants, was designed to enhance the smoke suppression and toxicity reduction performance of PVC materials without damaging their mechanical properties. After the addition of 15 wt% Y₂Sn₂O₇ (PVC/Y₂Sn₂O₇), the PVC composites achieved a V-0 rating, whereas the pure PVC material achieved a V-2 rating. The peak heat release rate of PVC/Y₂Sn₂O₇ composite was reduced from 282.7 kW/m² (pure PVC) to 243.6 kW/m². In addition, the maximum smoke density (Ds-max) of PVC/Y₂Sn₂O₇ was 263 m²/m², a decrease of 48.5% compared to pure PVC materials (511 m²/m²), indicating its outstanding ability for smoke suppression. Compared to Sb₂O₃, Y₂Sn₂O₇ can effectively reduce the release of the toxic gas CO (decreasing by 37.5%). Furthermore, the tensile strength of PVC can reach as high as 16.1 MPa. Compared with five widely used commercial flame retardants, Y₂Sn₂O₇ demonstrates superior performance, positioning it as a promising alternative to prospective candidates. Therefore, this study developed a rare-earth flame retardant and offers a promising design to improve the fire safety of PVC composites.

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 eco-friendly antifouling coatings suitable for demanding marine environments.

The poor degradability and limited recyclability of epoxy resins are key challenges hindering the efficient recycling of ex-service wind turbine blades (EWTBs). Herein, we proposed a selective degradation strategy for direct recycling and high-value recovery of epoxy resins by introducing degradable Schiff base groups into the molecular structure and utilizing the resulting oligomers as curing agents. To realize this strategy, a series of Schiff base compounds were synthesized using bio-based vanillin and diamines and subsequently functionalized with epichlorohydrin to yield bio-based epoxy resins. The cured epoxy resins demonstrated remarkable improvements in the mechanical properties of diglycidyl ether of bisphenol-A (DGEBA), with an increases of 44.49% in the tensile strength of 38.55%, bending strength, and impact strength of 71.20%. The introduction of dynamic Schiff base bonds enabled the selective degradation of the vanillin-2,2-bis[4-(4-aminophenoxy)phenyl]propane-based epoxy resin (VBEP)/DGEBA copolymer, producing 84.20% oligomers that can be directly recycled and reused. Replacing 30 wt% of the curing agent with the oligomer increased the tensile strength of the cured sample to 75.40 MPa, surpassing that of the cured DGEBA. Under simulated acid rain and seawater exposure, the copolymer exhibited a service life of 27 years at 40 °C, significantly exceeding the currently reported service life of 20 years. This study presents a sustainable strategy for the direct recycling and high-value reuse of epoxy resin, offering a promising solution for EWTBs.

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.

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.

A series of imido-vanadium(V) complexes bearing bidentate phenoxy-phosphine ligands were synthesized and characterized by NMR, elemental analysis, and single-crystal X-ray diffraction. These complexes demonstrated excellent catalytic performance in ethylene/1-hexene copolymerization, achieving high activities of 12.0×10⁶–49.0×10⁶ g_polymer ·(mol_V)^–1·h^–1 and affording random copolymers with tunable 1-hexene incorporations. These catalysts also exhibited ultrahigh activity, up to 112.2×10⁶ g_polymer ·(mol_V)^–1·h^–1, in ethylene/norbornene (NB) copolymerization, yielding cyclic olefin copolymers with adjustable NB incorporations. Remarkably, these catalysts demonstrated exceptional tolerance toward polar functional groups, enabling efficient copolymerization of ethylene with both 10-undecen-1-ol (U-OH) and 5-norbornene-2-methanol (NB-OH), incorporating about 2 mol% polar comonomers with high efficiency. Different with the catalytic behaviors in copolymerization of ethylene with nonpolar comonomers, the catalytic activities in E/U-OH copolymerization (25.7×10⁶ g_polymer ·(mol_V)^–1·h^–1) were much higher than those in E/NB-OH copolymerization (8.6×10⁶ g_polymer ·(mol_V)^–1·h^–1). DFT calculations revealed that the catalytic performance is governed by synergistic electronic and steric effects. For E/NB copolymerization, strong preference for cyclic olefins was attributed to favorable transition state stabilization. In polar comonomer systems, steric effects were predominant, with NB-OH exhibiting a larger buried volume around vanadium center upon coordination compared to U-OH. Overall, this work provides fundamental insights into vanadium-catalyzed (co)polymerization and offers new strategies for tailored polyolefin design.

Polymers that exhibit both biodegradability and chemical recyclability offer a promising solution to environmental pollution and resource scarcity. Poly(glycolic acid) (PGA) is a promising chemically recyclable polymer, characterized by its seawater degradability and high mechanical strength. In this study, aliphatic polycarbonates were synthesized through melt polycondensation and subsequently copolymerized with glycolide (GL) to produce chemically recyclable PGA based triblock copolymers with well-defined structures. The properties of these copolymers, including their thermal properties, crystallization behavior, and mechanical performance, can be effectively adjusted by modifying the structure and content of the middle block. Furthermore, an in-depth investigation reveals that the pyrolysis process involves ester exchange, radical, and back-biting reactions. In addition, the high-efficiency "Monomer↔Copolymer" chemical recycling loop has been established, achieving a remarkable yield exceeding 88% along with a purity greater than 99%.

The aim of this study is to develop magnetopolymer composites suitable for fabricating soft magnetoactive robots via extrusion-based 3D printing. Polysiloxane copolymers with urea fragments were synthesized and characterized, and their thermophysical and rheological properties were investigated. This study provides an assessment of the potential for their further use in additive manufacturing. The obtained materials were utilized as matrices for creating magnetically active polymer composites by incorporating microparticles of carbonyl iron. Samples of complex geometries were printed using both neat and filled filaments, demonstrating the feasibility of employing these materials in extrusion-based 3D printing.

Adjusting the structure of the hard segment (HS) represents a key method for manipulating the mechanical properties of thermoplastic polyurethane (TPU). This study developed a novel molecular design strategy to tailor TPU’s mechanical performance through altering the terminal diisocyanate structure of HS. The typical HDI-BDO based TPU was chosen as a model. Replacing HS’s terminal HDI residues with aromatic PPDI, TODI, and MDI (the corresponding TPUs are named as 2P, 2TO, and 2M, respectively) enabled broad tuning of TPU’s Young's modulus while maintaining high tensile strength and elongation. Compared with linear PPDI and TODI, the bent and unsymmetrical MDI exhibits greater deviation from the central axis of the middle HDI-BDO segment, which reduces HS’s capability of three-dimensionally ordered packing. Therefore, 2P and 2TO show higher hydrogen bond content and crystallinity, stronger physical crosslinking network, and thus much higher Young's modulus than 2M (75.6 MPa). Besides geometric structure, π–π stacking between HS’s terminal aromatic diisocyanates critically governs TPU’s physical crosslinking network. In 2P, π–π stacking induces torsion of the middle HDI-BDO segment and disrupts the neighboring hydrogen bonds, leading to a dense network with fine hard blocks. In contrast, the lateral methyl groups in TODI hinder π–π stacking, resulting in a sparse network with large hard blocks. Accordingly, 2TO exhibits a higher Young's modulus (146.2 MPa) than 2P (124.0 MPa), but greater strain-rate sensitivity.

Herein, we reported a Tb-carboxyl-imidazole coordination-crosslinked carboxylated nitrile butadiene rubber (XNBR) elastomer design that exhibits high mechanical robustness, fluorochromism, and white-light emission. Imidazole (Im), a toughening, sensitizing, and self-emissive ligand, highly intensified the fluorescence emission, remarkably toughened the elastomer, and imparted multistimuli responsiveness to the elastomer. The Tb³⁺ ions acted as cross-linking centers and provided high-temperature sensitivity of fluorescence emission (more sensitive than Eu³⁺ ions). The as-prepared XNBR/Tb/Im elastomer, with excellent puncture resistance, exhibited an ultimate extensibility of about 3100% and the highest tensile strength of 22 MPa. Experimental and theoretical investigations have demonstrated that Tb³⁺ ions are more likely to interact with Im ligands with increasing amounts of Im. The number of coordination cross-links with higher cross-linking functionalities showed an increasing trend during stretching. The elastomer exhibited an excitation wavelength and temperature-dependent green emission. By introducing red-emissive Eu³⁺ into the elastomer, a white-light-emitting XNBR/Tb/Eu/Im elastomer with chemo-fluorochromism was fabricated. The XNBR/Tb/Eu/Im elastomer exhibited stable white-light emission during both heating and stretching. Changing the temperature only resulted in a variation in the intensity of the white light. We demonstrated the potential applications of these elastomers in patterning and information anti-counterfeiting/encryption. This coordination crosslinked tough elastomer with fluorochromism and white-light emission paves a new way to fabricate soft devices and sensors, where optical information displays and optical signal responses are required.

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.

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.

Anion exchange membrane water electrolysis (AEMWE) synergize the kinetic merits of alkaline systems, zero-gap configurations and compatibility with non-noble metal catalysts, offering a promising pathway toward green hydrogen production. Nevertheless, practical exploitation was hindered by critical challenges: inferior alkaline stability, insufficient mechanical integrity, and detrimental hydrogen crossover of anion exchange membranes (AEMs), which compromise both device durability and operational safety. Here, we engineered a porous expanded polytetrafluoroethylene (e-PTFE)-reinforced poly(arylene quinuclidinium) membrane that enhances AEM mechanical robustness, prevents stress-induced rupture, and suppresses hydrogen crossover during electrolyzer operation. Specifically, the reinforced poly(arylene quinuclidinium) membrane (R-PTPQui) exhibited a tensile strength of 56 MPa and an elongation at break of 55%. Moreover, it effectively reduced hydrogen permeation in the electrolyzer, achieving an extremely low H₂-to-O₂ (HTO) value of 0.44 vol% at 0.1 A·cm⁻². The R-PTPQui-based electrolyzer achieved a high current density of 4.9 A·cm⁻² at 2.0 V and a Faradaic efficiency of 98.6% using a non-precious anode catalyst. These advances significantly strength the compatibility of poly(arylene quinuclidinium)-based AEMs for industrial-scale green hydrogen generation.

An efficient strategy has been developed to reconstruct chain folding and traversing of poly(L-lactide) (PLLA) during melt crystallization based on the selective hydrolysis of its amorphous regions. The molecular weights of the pristine PLLA (crystalline part), single stem, and single cluster were determined by gel permeation chromatography (GPC) according to their evolution during alkali hydrolysis. The maximum-folding-number (in a single cluster) and minimum-cluster-number (in one polymer chain) were obtained using these molecular weights. With the help of two numbers, the chain folding and traversing during the melt crystallization process (at 120 °C) of PLLA can be described as follows. Statistically, in a single polymer chain, there are at least 2 clusters consisting of up to 6.5 stems in each of them, while the rest of the polymer chain contributes to amorphous regions. Our results provide a new strategy for the investigation and fundamental understanding of the melt crystallization of PLLA.

Polycaprolactam (PA6) is an important engineering plastic known for its excellent strength and processability, making it widely applicable in the automotive and transportation industries. Previous studies have demonstrated that incorporating a small amount of organic-modified montmorillonite (OMMT) can significantly enhance the gas barrier properties of PA6. Based on PA6/OMMT, this study further introduced maleic anhydride-grafted ethylene-octyl copolymer (mPOE) and polytetrafluoroethylene (PTFE). Morphological characterization revealed the successful manipulation of the microstructure within this toughening system, revealing a distinctive tassel bundle morphology in the ternary blend of PA6/mPOE/PTFE. in the quaternary PA6/OMMT/mPOE/PTFE system, scanning electron microscopy (SEM) analysis demonstrated that the special “tassel bundle (TB)” morphology could induce an ordered arrangement of OMMT nanosheets, leading to synergistic improvements in both toughness and gas barrier performance. These findings offer promising potential for applications requiring simultaneously high gas barrier properties and enhanced toughness, particularly in hydrogen storage tanks and related industrial fields.

Due to environmental concerns and the oil crisis, biodegradable polymer foams have garnered increasing attention. Among all biodegradable materials, Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(HB-co-HV)) distinguishes itself with the advantage of being biodegradable in all natural environments. However, preparing P(HB-co-HV) foam with a fine cellular structure remains challenging. Herein, P(HB-co-HV) foams with a double melting peak structure were developed. P(HB-co-HV) samples were first heated briefly near the melting temperature to melt most of the crystals, followed by saturation and foaming at a lower temperature (foaming temperature). P(HB-co-HV) foams with cell sizes of 7.1−30.0 μm and relative densities ranging from 0.3 to 0.9 were prepared, and the foaming temperature window was as wide as 16 °C. The effect of heat treatment temperature and foaming temperature on the crystallization and cell structure was investigated through DSC and SEM. It was found that the high-melting temperature crystals generated during the saturation step significantly improved the cell structure of P(HB-co-HV), since these crystals can enhance the heterogeneous cell nucleation and hinder the cell growth during foaming. The low-melting temperature crystals were formed during foaming. In situ WAXD analysis during heating showed that the high- and low-melting peaks corresponded to HV-unit-excluded and HV-unit-included PHB crystals, respectively.

This study reports the fabrication of polypropylene (PP)-based microfiber webs (<1 µm) using a hybrid melt electrospinning/blown process with the aim of establishing a scalable and solvent-free platform for advanced lithium-ion battery separators. The primary objective was to address the inherent limitations of conventional melt electrospinning particularly the difficulty of achieving fiber thinning due to the high viscosity of polymer melts by incorporating auxiliary hot air flow and reducing the nozzle diameter from 1.0 mm to 0.3 mm. This modified configuration enables enhanced jet elongation and fiber diameter control under processing conditions relevant to industrial applications. The effects of nozzle temperature, hot air temperature, and applied voltage on fiber formation and jet behavior were systematically examined using high-speed charge-coupled device (CCD) imaging techniques. The results demonstrated that increasing both the hot air temperature and applied voltage significantly improved fiber thinning and uniformity, yielding an average fiber diameter of approximately 0.86 µm without evidence of thermal degradation. In contrast, elevated nozzle temperatures, while enhancing melt flowability, resulted in increased discharge rates and hindered fiber refinement when applied alone. These findings identify hot-air temperature as the most robust and controllable parameter for producing submicron fibers while maintaining the polymer integrity. Although the present study primarily focuses on morphological optimization and jet dynamics, future research will investigate the functional performance of fabricated microfiber webs as battery separators. Overall, the proposed hybrid process offers a technically feasible and environmentally sustainable route for the continuous production of fine PP-based fibers tailored for high-performance energy-storage applications.

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 coordination 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 those of 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.

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 coarse-grained 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.