With growing global focus on plastic circular recycling and sustainable development, chemical upcycling is gaining importance. It converts waste plastics into high-value products, avoiding the performance degradation and downcycling associated with conventional physical recycling processes. Polyimide (PI) is a high-performance polymer material, particularly valued in the field of lithium-ion batteries as a separator due to its high-temperature resistance, favorable mechanical strength, and good electrolyte wettability. However, its broader application has been limited by the high cost of its monomers and the energy consumption of its preparation process compared to conventional lithium-ion battery separators such as polyethylene/polypropylene. Here, we propose an effective strategy for the high-value application of recycled polyimide (PMDA/ODA-type) films through chemical catalysis: using lithium hydroxide to catalyze the partial ring-opening of the imide rings in recycled polyimide, transforming the insoluble and infusible recycled polyimide into a soluble poly(amic acid)-polyimide system (PAA-PI). This system is further processed via electrospinning to fabricate polyimide nanofiber membranes, which are applied as separators in lithium-ion batteries. They exhibit similar structural, thermal properties, and mechanical properties to the PI separators prepared by the traditional method, while also possessing good porosity, electrolyte wettability, and electrolyte uptake. Furthermore, batteries prepared using this recovered PI separator (RPI) exhibit excellent high-rate performance (135.55 mAh·g−1 at 5 C current) and long-term cycle stability (118.01 mAh·g−1 after 100 cycles at 0.5 C current, and 87.10 mAh·g−1 after 100 cycles at 2.0 C current), showing no significant difference compared to batteries prepared with conventional PI separators, while outperforming batteries prepared with commercial Celgard 2500 separators, essentially meeting the performance requirements of next-generation lithium-ion batteries. This work presents a strategy for the low-cost production of high-safety polyimide-based separators in lithium-ion batteries, enabling the high-value reuse of polyimide waste and thereby establishing a process consistent with green chemistry and sustainable development.
Phase equilibria were investigated in uncured mixtures composed of an epoxy oligomer, polysulfone, and tetraethoxysilane. Pairwise interaction parameters were calculated and binodal curves were constructed. The mutual diffusion coefficients of the components were determined and the influence of tetraethoxysilane on the diffusion processes in both binary and ternary systems was examined. Phase diagrams of the binary and ternary systems were established using optical microscopy and dynamic light scattering, and the boundary compositions corresponding to the single-phase region were identified.
Regulating donor–acceptor (D/A) and acceptor–acceptor (A/A) interactions is crucial for optimizing the morphology and charge dynamics of organic solar cells (OSCs). Herein, a tetraphenylethylene (TPE)-containing Y-series acceptor, TPE-HD, was developed through phenylalkyl side-chain engineering to manipulate the intermolecular interactions and crystallization behavior. The introduced TPE unit enhanced A/A self-aggregation and molecular ordering, leading to increased crystallinity and accelerated crystallization kinetics during film formation. The binary D18:TPE-HD blend exhibited pronounced aggregation characteristics and delivered a power conversion efficiency (PCE) of 17.5
Conductive hydrogels with high mechanical strength, good adhesion, and high sensitivity are highly demanded for wearable electronics. A multifunctional hydrogel based on 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and acrylic acid (AA) was synthesized via free-radical polymerization. The system incorporates dynamic hydrogen bonds from guanine–cytosine (G–C) base pairs and homogeneously dispersed carbon nanotubes (CNTs) modified using a dual-ionic liquid strategy. Short-chain (C4) and long-chain (C12) imidazole-based ionic liquids act synergistically to exfoliate and stabilize CNTs, facilitating uniform dispersion and strong interfacial bonding. Owing to the continuous conductive pathways formed by the CNTs, the hydrogel exhibited enhanced electrical conductivity with a gauge factor of 5.61, together with excellent short-term cyclic stability and responsiveness for monitoring dynamic human motions. The combination of covalent cross-linking, reversible hydrogen bonding, and reinforced nanofillers endows the hydrogel with high stretchability, good adhesion (5.5 kPa), and superior fatigue resistance, showing great potential for use in flexible wearable bioelectronics.
Self-healing polyurethane (PU) elastomers will greatly extend the service life of key components, reduce maintenance costs, and promote sustainability. However, dense hydrogen bonds cannot quickly recover after stretching, causing permanent deformation, while high-temperature and long-duration curing are required for their crosslinking. Therefore, dual crosslinked networks are designed herein to achieve self-healable, high-resilience and UV-curable polyurethane-urea elastomers (PUU-SS-Zn), using polycarbonate diol (PCDL) as the soft segment for entropic elasticity, cystamine (Cy) as a chain extender for disulfide bonds and urea-linked hydrogen bonds, 2-hydroxyethyl acrylate (HEA) as end-capping groups for rapid UV-curing, ZnCl2 for metal coordination bonds. The resultant elastomers are UV-cured within 100 s, exhibit a transmittance >92
Polypropylene (PP) can be toughened by adding elastomers or constructing core-shell structures, although the toughening efficiency of both approaches is limited. Herein, a synergistic dual-phase toughening method is proposed by introducing high-density polyethylene (HDPE) into ethylene-propylene rubber (EPR) and isoprene rubber (IR) composite systems. This resulted in an HDPE@EPR core-shell particle structure alongside finely dispersed IR particles. Interfacial tension promotes adhesion between the EPR shell and IR, concurrently reducing the size of the IR domains and interparticle spacing of the rubber phase. By optimizing the HDPE content, a loading of 15 phr resulted in a well-defined core-shell morphology with minimized IR domains. This enables the fabrication of a PP alloy exhibiting exceptional low-temperature impact toughness (35.8 kJ/m2 at −20 °C) and an optimal strength-toughness balance. However, surpassing the optimal HDPE content triggers IR particle aggregation, because the thinned EPR shell fails to fully encapsulate the HDPE core, while interfacial tension-driven repulsion facilitates this process. Finite-element simulation results demonstrated a significant synergistic toughening effect between the HDPE@EPR core-shell particles and IR particles. Under low-temperature impact loading, stress and strain are concentrated at the core-shell interface and around the IR particles, which effectively inhibits rapid crack propagation, thereby significantly enhancing the low-temperature toughness of the material. This dual-dispersed phase design strategy offers a promising pathway for the development of high-performance PP composites for demanding low-temperature applications.
The precise microstructural origin of cavitation in semicrystalline polymers remains a subject of persistent controversial. Consequently, the exact spatial initiation of voids within a single spherulite remains under debate. Resolving this ambiguity has long been hindered by the spatial resolution limits of the conventional characterization techniques. To overcome this limitation, we employ an integrated approach of in situ synchrotron microfocus X-ray scattering and ultrasmall-angle X-ray scattering to investigate the cavitation behavior within individual isotactic polybutene-1 spherulite during uniaxial stretching. It turns out that early-stage voiding exhibits a distinct spatial sequence. Structural damage preferentially initiates at the spherulitic center, subsequently emerges in the equatorial region, and ultimately propagates to polar regions. By reconstructing the three-dimensional lamellar orientation within the undeformed spherulite, we revealed that lamellae oriented parallel to the stretching direction are extensively distributed across all spherulitic regions. Based on these findings, we propose a micro-mechanical cavitation model. In this framework, parallel lamellae undergo direct mechanical fragmentation under stress, with microvoids nucleating within the interstitial gaps between adjacent crystalline blocks.
As energy storage technologies move toward safer and mechanically adaptive formats, flexible solid-state batteries have become an important platform for powering next generation deformable systems. Solid polymer electrolytes (SPEs) are promising candidates for flexible solid-state batteries because their polymer-chain flexibility, film forming capability, and interfacial adaptability enable stable solid-solid electrode-electrolyte contact under low pressure or pressure free conditions. This review summarizes recent advances in SPEs for flexible solid-state batteries, covering linear polymers, topological polymer architectures, composite and multifunctional electrolytes, and representative fabrication strategies. Application oriented SPE designs are further discussed with a focus on material and device strategies for deformation adaptability, safety enhancement, and environmental adaptability. Finally, remaining challenges and future directions are outlined to guide the rational design of high performance SPEs for flexible energy storage.
In this study, a phthalonitrile monomer containing a maleimide group (MPN) with a melting point of 106.8 °C was successfully synthesized. Differential scanning calorimetry (DSC) showed that the MPN resin can act as an autocatalyzed resin without any curing agent. The monomer was then cured using diallyl bisphenol A (DABA) as the curing agent. Based on the results of FTIR analysis, a suitable curing cycle was established. Given the dual-stage curing behavior of the monomer, three composite samples were fabricated using three different curing cycles to investigate the relationship between the polymer structure and final properties. Interlaminar shear strength (ILSS) tests showed that samples with approximately 95
Magnesium alloys suffer from severe corrosion in chloride-containing environments, which significantly restricts their structural application. In this study, a core-shell smart nanocontainer (PHIO@ZIF-8/PST, denoted as PZS) was constructed by integrating a pH-responsive metal–organic framework reservoir with an in situ assembled poly(sodium thioctate) (PST) functional shell, and further incorporated into an epoxy matrix to develop an intelligent anticorrosion coating. The ZIF-8 core serves as an efficient loading platform for a chelating corrosion inhibitor (PHIO) and provides pH-triggered release capability, whereas the PST shell simultaneously enhances interfacial compatibility and introduces additional chemical protection. Structural analyses confirmed the successful construction of the core-shell architecture and the preservation of crystallinity after functional modification. Electrochemical and ion-release studies demonstrated that PZS nanocontainers exhibited pronounced pH-responsive behavior, enabling accelerated inhibitor release under acidic or alkaline conditions. When incorporated into the epoxy (EP) coating, PZS significantly improved the interfacial densification, reduced the defect density, and prolonged the diffusion pathways for aggressive species. Long-term electrochemical impedance spectroscopy and salt spray tests revealed that the PZS/EP coating maintained impedance values three orders of magnitude higher than that of the pristine epoxy after 28 days of immersion, indicating outstanding corrosion resistance. The enhanced performance arises from the synergistic coupling of the physical barrier reinforcement, inhibitor chelation, and in situ formation of protective Mg–PST complexes at active corrosion sites. This study provides a generalizable strategy for constructing multifunctional smart coatings for the durable protection of lightweight metal substrates.
Vascular closure devices (VCDs) play a critical role in preventing bleeding and hematoma formation after percutaneous interventions. Despite effective mechanical hemostasis, the current collagen-based VCDs lack anti-inflammatory and regenerative capabilities. Herein, we report the development of a polydopamine (PDA)-modified collagen sponge (Col@PDA) to enhance the anti-inflammatory and pro-regenerative potential of collagen-based materials. PDA modification not only preserved the sponges’ inherent porosity and swelling behavior but also endowed them with immunomodulatory functions. In vitro, the modified sponges exhibited superior anti-inflammatory and antioxidant activities in RAW 264.7 macrophages and L929 fibroblasts. In a rat subcutaneous implantation model, Col@PDA attenuated local inflammation, promoted dermal regeneration, and enhanced collagen deposition and angiogenic factor expression. Collectively, PDA modification enables collagen sponges to actively modulate the healing microenvironment, resulting in faster tissue repair than unmodified collagen sponges.
Hydrogel actuators with intrinsic softness, biocompatibility and large deformability hold great promise for extensive applications in intelligent autonomous soft robotics. However, achieving directionally controllable autonomous motion under constant stimulation remains a key challenge, primarily due to the isotropic and densely crosslinked nature of conventional hydrogel networks, which limits both directional driving forces and efficient mass transport pathways. Here, we report a simple method for the fabrication of curved cylindrical hydrogels with aligned porous channels that enable autonomous rolling under constant light irradiation via directional freezing assembly-assisted in situ photopolymerization. Benefiting from the oriented open-cell network, the hydrogel exhibited fast light-responsive deformation with bending and recovery speeds of 16.5 (°)·s−1 and 24 (°)·s−1, respectively. Notably, the hydrogel achieved self-sustained rolling under constant light irradiation at a speed of 0.77 mm·s−1, arising from the synergy of structural anisotropy and geometric curvature. By spatially modulating the irradiation region, the photo-guided direction-steerable rolling could be realized. Additionally, the hydrogel implemented multiple tasks including obstacle crossing, stair climbing and cargo transport, highlighting its potential in biomimetic soft robotic systems.
Advanced aerospace technologies demand polymer-based wave-transparent materials with low dielectric constant (Dk), low dissipation factor (Df), and high heat resistance for hypersonic vehicles. Thermosetting polyimides (PIs) from phenylethynyl-terminated imide (PETI) oligomers are promising candidates due to their excellent thermal stability; however, their application is limited by high Dk and Df at high frequencies and processing difficulties. Here, a series of PETI oligomers were designed and synthesized by polycondensation of 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride containing a Cardo structure, and six diamine monomers, respectively. The diamines were divided into three pairs by backbone flexibility, with each pair comprising a non-fluorinated diamine and its trifluoromethyl (—CF3) substituted analog. The effects of chain segment flexibility and — CF3 substitution on the processability of the oligomers and the properties of the cured PIs were systematically investigated. Results show that oligomers with — CF3 groups exhibit enhanced solubility and improved viscosity stability at 270 °C compared to their non-fluorinated counterparts. Moreover, the corresponding cured resins show lower Dk and Df values while maintaining good thermal stability and mechanical properties. Notably, the BPAF-FA system exhibits favorable properties: an oligomer solubility of 40 wt
Hydrogen peroxide (H2O2) is a green chemical with extensive applications in chemical synthesis and environmental remediation. While the industrial anthraquinone process remains the dominant production method, solar-driven photocatalytic H2O2 production has emerged as a promising strategy to complement or optimize current production models, particularly for on-site applications. Among various porous organic polymers (POPs), covalent organic frameworks (COFs), and covalent triazine frameworks (CTFs) have attracted significant attention as a premier platform due to their modular construction and precise molecular-level tunability. Here, we systematically summarize recent progress in POPs-based photocatalysts, with a primary focus on the structural and functional modification of COFs and CTFs. We first elucidate the fundamental principles and existing challenges of photocatalytic H2O2 production. Subsequently, the research landscape of various POPs materials in photocatalysis is discussed. Taking COFs and CTFs as representative examples, we then highlight advanced modification strategies, including the design of donor-acceptor (D-A) structures, functional group engineering, and the construction of heterostructures. These strategies effectively facilitate efficient charge separation, extend carrier lifetimes, and improve mass transport, thereby enhancing solar-to-chemical conversion efficiency. Finally, we summarize the current state of the field and offer perspectives on future research directions for POPs-based photocatalytic H2O2 production.
Conventional chemotherapy and radiotherapy damage normal tissues due to off-target toxicity, impairing patient prognosis. Chemoradiotherapy (CRT)—the concurrent use of chemotherapy and radiotherapy—has gained considerable attention, as it suppresses primary tumors and reduces metastasis. However, dose-limiting drug toxicity remains a major barrier to clinical CRT. To mitigate adverse effects and improve drug bioavailability, nano-sensitizer (NS)-mediated CRT has become a research focus. Nonetheless, unique tumor microenvironmental features, including hypoxia, abnormal vasculature, elevated reactive oxygen species, mild acidity, dense extracellular matrix, and immunosuppression, severely compromise NS efficacy. Accordingly, smart NS designed to surmount these microenvironmental barriers represent a key direction in drug development. This review summarizes recent advances in tumor microenvironment-targeted NS and their preclinical and clinical applications, aiming to deepen understanding of microenvironmental challenges in CRT and facilitate the development of potent NS.
Intrinsically emissive helical poly(phenylacetylene)s (PPAs) are attractive circularly polarized luminescence (CPL) materials, yet their color tunability and light-harvesting capability remain limited because the emission mainly originates from the backbone excited states. Herein, we construct side-chain/backbone bichromophoric PPA systems to investigate Förster resonance energy transfer (FRET) and its effect on CPL performance. Using a pentafluorophenyl ester-functionalized PPA-PFP as a common precursor, planar aromatic donors, pyrene (Py) and naphthalene (Nap), and a non-coplanar donor, triphenylamine (TPA), were systematically introduced through activated-ester amidation. Py-PPA and Nap-PPA both underwent efficient donor-to-backbone energy transfer to the emissive cis-cisoid helical backbone, while Py-PPA showed a higher FRET efficiency and a much more pronounced solid-state CPL enhancement, with a ∣glum∣ value of 7×10−2 in the film. In contrast, TPA-PPA exhibited conformation-coupled FRET attenuation and emission color switching because the bulky twisted donor destabilized the cis-cisoid back-bone. Further spectroscopic and diffraction studies revealed that the superior CPL performance of Py-PPA originated from the synergistic combination of stronger pendant chiral ordering and more efficient side-chain-to-backbone energy transfer during solution aging and film formation. These results show that donor-pendant modification is an effective way to regulate FRET and CPL in intrinsically emissive PPA systems.
Biodegradable polymeric nanocarriers demonstrate significant potential for the controlled release of pesticides, offering a sustainable and efficient approach for agriculture. This study involves the synthesis of novel pH-responsive L-cysteine-conjugated polydopamine (PDC) nanospheres for the controlled release of emamectin benzoate (EMB). Using sustainable in situ polymerization, hydrophobic EMB was encapsulated within biodegradable polydopamine (PDA), which was further conjugated with L-cysteine. The functionalized and encapsulated carriers were characterized using UV-visible spectroscopy, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), zeta potential, field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), and X-ray photoelectron spectroscopy (XPS). Both EMB@PDA and EMB@PDC nanospheres were assessed for their encapsulation efficiency and pH-responsive release of EMB. Under varying pH and temperature conditions, the maximum cumulative release of EMB was achieved at pH=3 and was further enhanced by temperature. Various kinetic models have shown that Fick’s diffusion controls the release process. EMB@PDC nanospheres exhibited excellent adhesion to plant surfaces and effectively protected against UV radiation, which reduced EMB loss through rainfall washout and photolytic degradation. In addition, EMB@PDC exhibited high insecticidal potency against Pieris brassicae. Hence, this integrative platform exemplifies an effective pesticide delivery system for promoting agricultural sustainability.
Metal-backboned polymers have been proposed as a new class of materials with remarkable physical and chemical properties for applications in optoelectronics, magnetism, and energy. However, the number of metal atoms in their backbones is limited to less than 30 to date. This has prevented the systematic investigation of their properties. Herein, we report the synthesis of metal-backboned polymers with a polymerization degree of 169. Using gold as a model system, we identified that the controlled release of Ag+, an electron-donating imidazole co-ligand, ligand steric/electronic effects, and elevated reaction temperature are key to achieving such long chains. The resulting metal-backboned polymers display hallmark polymer behaviors such as glass transition, together with a unique electronic structure featuring pronounced electron de-localization along the Au backbone and efficient room-temperature phosphorescence. This work provides an effective route to long-chain metal-backboned polymers and deepens the understanding of the electronic structures in one-dimensional metal backbones.
The helical structures found in biological systems, such as DNA, have inspired significant research interest in artificial helical polymers, owing to their strong potential for applications including chiral recognition and resolution, asymmetric catalysis, and other related areas. However, the preparation of single-handed helices from achiral starting materials, as well as the exploration of their chiral resolution behavior, continues to represent a considerable challenge. In this work, we present the rational design and synthesis of optically active helical poly(phenyl isocyanide)s through helix-sense selective polymerization (HSSP) of achiral phenyl isocyanide monomers, catalyzed by enantiopure Pd(II) complexes bearing S- or R-configured ligands (Pd(II)/LS or LR). The polymerization exhibits living and controlled characteristics, allowing for the precise modulation of molecular weights (Mn) with exceptionally narrow distributions (Mw/Mn). The resulting polymers exhibit intense optical activity and demonstrate outstanding performance in chiral recognition. Specifically, these chiral materials are utilized as a chiral stationary phase (CSP), which can separate various racemates including α-methylbenzylamine, cobaltic acetylacetonate, and 2-hydroxy-2-phenylacetophenone. Additionally, when applied as a chiral crystallization agent, the polymer enabled the resolution of racemic Z-Alanine via enantioselective crystallization, yielding an enantiomeric excess (ee) as high as 81
The development of conductive hydrogels with stretchability, adhesiveness, self-healing, antibacterial and ionic conductivity is crucial for wearable electronic devices such as motion and health monitoring sensors and flexible generators. In this study, a novel multifunctional conductive hydrogel with high conductivity, excellent stretchability, antibacterial property, antifreeze and moisture retention, as well as self-healing and self-adhesive capabilities was successfully prepared by introducing the dynamic redox reaction between phenolic hydroxyl groups and Fe3+ through the addition of tannic acid (TA) to the acrylic acid (AA)-based hydrogel system, and the addition of LiTFSI. This material not only has good mechanical flexibility (tensile strength of 0.3048 MPa and elongation at break of 1657
