This study develops an effective molecular isomerization strategy to enhance photocatalytic hydrogen peroxide (H₂O₂) production by leveraging the structural tunability of benzobisthiazole (BT)―an electron-deficient planar heterocycle with superior optoelectronic properties and chemical stability. Unlike conventional isomeric covalent organic frameworks (COFs) which focus on symmetric or unidirectional conjugation systems, we exploit the two orthogonal π-conjugation pathways (2,6- versus 4,8-substitution) of BT to construct regioisomeric COFs with distinct topological connectivity, a design that remains rarely explored for photocatalytic H₂O₂ generation. Utilizing subsitution-position flexibility of BT, two regioisomeric monomers, namely 2,6-BT-CHO and 4,8-BT-CHO_pro, were designed and polymerized into highly crystalline donor-acceptor (D-A) covalent organic frameworks (COFs): 2,6-BT-COF and 4,8-BT-COF. These COFs exhibit high surface areas, extended π-conjugation, and excellent light-harvesting capabilities, rendering them ideal photocatalysts. Remarkably, under visible-light irradiation in pure water, 2,6-BT-COF achieved a H₂O₂ production rate of 1638 μmol·g^–1·h^–1, outperforming 4,8-BT-COF (1046 μmol·g^–1·h^–1) by about 57%. Structural and photophysical analyses reveal that this pronounced performance difference stems from the critical influence of molecular topology on charge separation, exciton dissociation, and redox kinetics. Specifically, 2,6-BT-COF facilitates more efficient intramolecular charge transfer and suppresses charge recombination losses compared its 4,8-substituted counterpart. This work not only presents two novel, structurally well-defined COF photocatalysts but also establishes a design principle for optimizing photocatalytic efficiency through precise control of molecular connectivity.

Covalent organic frameworks (COFs) are synthesized from organic building blocks through covalent bonds, constituting a class of crystalline organic polymers. They are characterized by well-defined periodic structures, uniform and permanent pores, high porosity, customizable functionalities, high chemical and thermal stability, and tailored topological architectures. The customizable functional groups and tunable pore environments can be integrated into the infinitely extending skeletons of COFs, facilitated by an extensive toolbox of molecular synthesis. This versatility has garnered significant interest across various fields. However, the large-scale production of functional COFs is highly desirable to meet the growing demand for various applications, yet it remains constrained by high costs and the low efficiency of current synthesis methods. Among the synthesis methods for COFs, solvothermal synthesis remains the dominant approach, while, it faces significant challenges such as prolonged reaction times, reliance on organic solvents, high temperature and pressure conditions, complex operational procedures, and environmental unsustainability. The microwave-assisted method for synthesizing COFs can rapidly and uniformly transfer reactive energy at the molecular level due to its unique volumetric heating mechanism. This approach offers a promising solution to the challenges associated with conventional synthesis methods for COFs. This review systematically includes recent research advances in microwave-assisted synthesis (MAS) of COFs, organized by their linkages, topologies, and synthesis methods. It compiles key synthesis parameters and material properties, along with fundamental aspects concerning COFs and microwave interactions. Current challenges and prospects in this field are also discussed.

Porous polymer fibers, which integrate polymer flexibility with high surface area and tunable porosity, represent a burgeoning class of functional materials. Unlike previous reviews that focused on electrospun porous fibers or porous materials used for specific energy/separation functions, this review focuses on fibers and systematically explores their controllable synthesis from a cross-process perspective. These include electrospinning-assisted pore-forming techniques, phase separation, template processing, 3D printing, and key structure-function relationships that determine their properties. Key applications include environmental remediation (filtration and adsorption), energy storage (batteries and supercapacitors), biomedical engineering (tissue scaffolds and drug delivery), and advanced smart textiles. This further highlights emerging trends toward smart/wearable integration and the hybridization of porous fibers with advanced porous frameworks and conductive components. This review is expected to provide a viable research direction for porous polymer fibers.

sp²-Carbon-conjugated organic frameworks (sp²c-COFs) are a class of porous crystalline polymers constructed through the ordered linkage of building blocks via vinylene bonds. Because of their high specific surface area, extended planar π-conjugation, and remarkable stability, sp²c-COFs are regarded as highly promising novel photocatalysts. This review begins by introducing the design principles and synthetic methods for sp²c-COFs. Subsequently, various strategies for enhancing photocatalytic performance have been summarized, including designing donor-acceptor (D-A) structures, crafting charged frameworks, developing heterojunctions, and modifying covalent organic frameworks (COFs) pore channels. We then elaborate on the applications of sp²c-COFs in photocatalytic H₂ production, H₂O₂ production, CO₂ reduction, organic transformation reactions, and uranium extraction from seawater. Finally, the challenges and future prospects of sp²c-COFs for practical applications in photocatalysis were discussed.

The urgent global demand for clean energy has positioned proton exchange membrane fuel cells (PEMFCs) as a pivotal technology owing to their high efficiency and environmental friendliness. Their performance critically relies on the proton exchange membranes (PEMs). Recently, integrating covalent organic frameworks (COFs) into conventional proton-conducting polymers has gained increasing, as this strategy is expected to combine the structural advantages of COFs with polymer flexibility to develop advanced PEMs. This review briefly outlines the current types of PEMs and the COF design for proton conducting. Then the fabrication strategies and evaluation methods are introduced. The design of COF-modified Nafion and sulfonated polyetheretherketone (SPEEK) for low-humidity proton conduction, as well as COF-modified polybenzimidazole (PBI) for high-temperature proton conduction were summarized, with particular emphasis on COFs forming continuous “proton highways” within polymer matrices for enhanced conduction while leveraging molecular sieving to suppress fuel crossover and thus improve cell efficiency and safety. Finally, critical challenges and outlook of COF-modified PEMs are discussed, such as interfacial compatibility, COF agglomeration, and the long-term stability and scalability under harsh conditions, which severely hinder the practical applications. Potential solutions are proposed, including in situ growth, hierarchical pore design, and gradient doping, to improve interfacial compatibility while maintaining excellent mechanical properties, as well as the development of intelligent and multifunctional PEMs.

Crude oil has long been the "black gold" of the global economy, and its fractionation relies on thermal distillation, a highly energy-intensive process. In contrast, crude oil fractionation via membrane separation can operate under mild conditions, avoiding phase transitions, and thereby substantially reducing the energy consumption associated with thermal separation processes. Numerous microporous polymer membranes have been developed to target the fractionation of oil mixtures through precise molecular design and structural modulation for the selective separation of hydrocarbon compounds. However, the intrinsic trade-off between permeance and selectivity remains a core bottleneck limiting their advancement. Herein, we summarize the synthetic strategies for microporous polymer membranes, focusing on tailored pore structures, anti-swelling capabilities, and selective transport of hydrocarbon compounds across these membranes. The performance of representative materials for practical crude oil fractionation was also highlighted. We also outline critical unresolved challenges, including cost-efficient large-scale fabrication, long-term stability under harsh crude oil environments, and further optimization of the permeance-selectivity balance, issues that must be addressed to promote the deployment of microporous polymer membranes.

Dynamic covalent chemistry (DCC) is a type of reversible chemical reactions under the control of thermodynamics. The reversibility of DCC allows the exchange of reaction components to form thermodynamically stable products. This kind of reaction has been widely incorporated in various research directions, holding an important significance in guiding emerging fields, such as two-dimensional macrocycles, two-dimensional materials and three-dimensional molecular cages. Of them, covalent organic frameworks (COFs), as a class of high crystalline porous conjugated polymers linked by dynamic covalent bonds exhibit huge potential application in various fields, such as gas separation, catalysis, sensing, biomedicines, and electronic devices due to their long-range ordered structures, regular pore distribution, high specific surface areas, and excellent molecular material designability. Vinylene-linked COFs feature high chemical stability and outstanding π-electron delocalization, extremely desired for the development of high-performance semiconducting catalysts and device. However, given that the formation reaction of carbon-carbon double bond only exhibited much poorer reversibility than those of the traditional dynamic covalent bonds, it still a big challenge to well-control the preparation of high-quality vinylene-linked COFs. In this review article, we intend to summarize the synthetic strategy approach to 2D vinylene-linked COFs on the basis of the rational design of the key monomers and the optimized reaction conditions for efficiently promoting Knoevenagel/aldol condensation. Then, we exemplified several applications arising from the unique characters of such kinds of COFs. Eventually, the challenges and opportunities of vinylene-linked COFs were also foreseen.

Wounds are a critical issue in human health care. Consequently, clinical management of wounds is crucial for wound care. Significant advancements have emerged in wound-care applications over the past few decades. There are various types of wound-care applications, including wound dressings. Wound dressings have garnered significant interest from researchers in recent years. Wound dressing materials significantly influence the wound-healing process. Numerous varieties of wound dressings, including hydrogels, have been developed. Owing to their exceptional mechanical and biochemical properties, hydrogel wound dressings have demonstrated significant advantages in the domain of wound care. Various polymeric materials, including natural and synthetic polymers, have been extensively utilized in the fabrication of hydrogel wound dressings. Numerous innovative and successful hydrogel wound dressings have been developed. This review focuses on the utilization of polymeric hydrogels in wound dressings and wound healing applications.

This study focuses on the development and optimization of electrode materials composed of covalent organic frameworks (COFs) integrated with carbon nanotubes (CNTs) for lithium-ion battery applications. The findings reveal that incorporating CNTs into COFs markedly enhances their electrochemical performance by reducing charge transfer resistance and accelerating charge transport kinetics. Impressively, the COFs/CNT composites delivered a high specific capacity of 307 mAh·g^–1 at a low current density of 0.05 A·g^–1 and maintained strong capacity retention even at elevated current densities. Furthermore, the composites demonstrated outstanding cycling stability and structural robustness, retaining significant capacity after 1000 charge/discharge cycles.

Conjugated microporous polymers (CMPs) have demonstrated significant potential for gas separation due to their permanent microporosity, high adsorption capacity, and exceptional chemical robustness. However, the scalable, cost-effective and environmentally friendly synthesis of CMPs as an alternative to energy-intensive traditional solvothermal methods remains underexplored. Herein, we present a solvent-free, flux synthesis method for constructing olefin-linked amorphous CMPs (NKCMP-1 and NKCMP-2) through Knoevenagel condensation of 2,3,5,6-tetramethylpyrazine with linear aromatic aldehydes. This method surpasses ionothermal and mechanochemical routes in terms of scalability and product uniformity. Notably, NKCMP-1 can be synthesized on a kilogram scale (0.54 kg) while maintaining structural integrity, high surface area and a uniform microporous architecture. Both NKCMP-1 and NKCMP-2 exhibit outstanding C₂H₂/CO₂ selectivity and cyclic stability under ambient conditions, as confirmed by dynamic breakthrough experiments. These features make the developed CMPs highly promising for real-world industrial gas purification applications.

Efficient detection of nitroaromatic explosives remains a great challenge, and covalent organic frameworks (COFs) incorporating aggregation-induced emission (AIE) units provide a promising platform for high-performance fluorescent sensing. Herein, we designed and synthesized both two-dimensional (2D) and three-dimensional (3D) AIE-active COFs to systematically investigate how dimensional differences (pore architecture, charge transfer efficiency, and AIE behavior) regulate sensing performance. Through a “4+4” imine condensation strategy, a 2D sql topological COF (TPPDA-TPTPE) was obtained from a planar tetraamine (TPPDA), whereas a 3D pts topological COF (JUC-646) was constructed from a twisted tetraamine (BMTA) with T_d geometry—using the same TPTPE linker. Both COFs exhibit high crystallinity, stability, and strong AIE-derived luminescence, but show strikingly different sensing performances. In particular, JUC-646 achieves a quenching constant of 6.99×10⁴ L/mol toward 2,4,6-trinitrophenol (TNP), nearly five times higher than that of TPPDA-TPTPE. This superior performance originates from the 3D open-channel structure (facilitating analyte diffusion), enhanced host-guest interactions, and energetically favorable photoinduced electron transfer—all of which are derived from dimensional differences. This comparative study explicitly establishes a structure-function relationship between framework dimensionality and sensing performance, offering direct guidance for the rational design of AIE-active COFs with tailored dimensionality for efficient explosive detection.

Solar-driven interfacial evaporation provides a sustainable solution to freshwater scarcity. However, its practical use is hindered by salt crystallization, the mechanical fragility of existing evaporators, and the substantial low-grade heat generated during evaporation, which is seldom utilized. Herein, drawing functional inspiration from the efficient mass-transport characteristics of the lotus root, we design a biomimetic polymerized high internal phase emulsion (PolyHIPE)-hydrogel composite (SH@FPCP) featuring an interpenetrating network. The interconnected macropores act as rapid vapor-escape pathways, while hydrogel filaments threaded through the pores continuously replenish water and dissolve accumulating salts. The fluorinated polypyrrole-modified PolyHIPE framework provides a strong photothermal response under solar irradiation. The SH@FPCP evaporator delivers a high evaporation rate of 3.19 kg·m⁻²·h⁻¹ with stable salt-resistant operation for over one week. The compressive strength increases to 1298 kPa at 5% strain, highlighting substantial mechanical reinforcement compared with the unmodified hydrogel. Moreover, the SH@FPCP evaporator enables thermoelectric power generation, delivering a power density of 720 mW·m⁻² and an open-circuit voltage of 110 mV. This study provides a novel material design strategy for developing durable and high-performance solar evaporation systems.

Conjugated covalent organic frameworks (COFs) possess distinct advantages over amorphous organic photocatalysts, including high charge transfer efficiency and effective light utilization. However, their photocatalytic performance often declines under prolonged solar irradiation in air, largely owing to their limited photostability. In this study, we systematically investigated the photobleaching mechanism of vinylene-linked COFs synthesized via aldol condensation between 2,4,6-trimethyl-1,3,5-triazine and aldehydes. When the COF contains phenylene as the linker, oxygen can undergo photoinduced addition across the vinylene bond, leading to cleavage of the vinylene bonds and the formation of terminal aldehydes, thereby causing photobleaching. Mechanistic studies indicated that superoxide anion radicals play a key role in this oxidative degradation process, accompanied by the partial cycloaddition of adjacent vinylene bonds. To enhance photostability, we incorporated naphthyl groups into the framework at the strut, replacing phenylene to modulate the excited-state electronic structure at the vinylene linkages. The newly synthesized COF exhibited notable anti-photobleaching capability in the presence of oxygen. This work not only deepens the understanding of photodegradation mechanisms in conjugated COFs but also offers valuable insights for the design and application of photostable COF-based catalysts.

Two-dimensional covalent organic frameworks (2D COFs), characterized by tunable optoelectronic properties and well-defined porous architectures, have emerged as promising photocatalysts for solar-driven H₂O₂ production. Although network topology exerts a profound impact on the optoelectronic characteristics of 2D materials, achieving precise regulation of their topology remains a significant challenge. In this study, we report two topologically isomeric 2D COFs constructed from the same building blocks, namely ETBA-kgm-COF with a kgm topology and ETBA-sql-COF with a sql topology. Particularly, the isomeric COFs with same chemical compositions provide an ideal platform to isolate and elucidate intrinsic topological effects in 2D COFs. Comprehensive characterizations reveal that the sql topology facilitates efficient charge separation and transfer, thereby enhancing photocatalytic performance. Moreover, without any sacrificial agents, ETBA-sql-COF exhibits a superior photocatalytic H₂O₂ production rate up to 2042 μmol·g^–1·h^–1, which is 1.57 times that of ETBA-kgm-COF (1303 μmol·g^–1·h^–1). This work provides an in-depth investigation into topology-property relationships in COFs and offers a rational strategy for the design and synthesis of high-performance photocatalysts.

With the increasing severity of environmental pollution and the severe threat posed by heavy metal ions, the development of adsorbents with high capacity and selectivity for toxic metal species has attracted increasing attention. Porous organic polymers (POPs) feature large surface areas, diverse building units and linkages, as well as highly tunable structures, making them promising candidates for water purification. In this work, three POPs bearing different substituents were synthesized via a furan-maleimide Diels-Alder reaction. Their adsorption performance toward hexavalent chromium [Cr(VI)] was systematically evaluated. The results show that all three POPs exhibited the highest Cr(VI) uptake at pH=1. Kinetic studies revealed that the adsorption process followed a pseudo-second-order kinetic model, while the equilibrium data were well described by the Langmuir isotherm, indicating monolayer adsorption on homogeneous sites. Among the three POPs, Por-OMe, which incorporated an electron-donating methoxy group, displayed the highest adsorption capacity for Cr(VI), reaching 697.4 mg/g. These results demonstrate that furan-maleimide Diels-Alder chemistry provides an effective strategy to construct functional POPs and that electronic modulation of the framework is a viable approach to enhance Cr(VI) adsorption performance.

Oral ulcers, a prevalent oral mucosal condition, involve epithelial discontinuity, tissue fluid loss, reactive oxygen species accumulation, and bacterial infection. Dynamic saliva flow and physical friction from food residues further aggravate the damage and delay healing. To address this problem, we developed a stable PolyLA-based adhesive patch by combining α-lipoic acid (LA) and betaine (BET) using a simple one-step solvent evaporation method, referred to as PolyLA/BET. The carboxylate and tertiary ammonium groups on BET formed multiple hydrogen bonds with PolyLA, effectively inhibiting the depolymerization of LA. PolyLA/BET firmly adheres to oral tissues via hydrogen bonding mediated by surface carboxyl groups. Moreover, zwitterionic structure of BET enabled the patch to absorb and retain water. Upon hydration, the patch maintains structural stability while acquiring flexibility and adhesiveness, which are essential characteristics for durable sealing and the formation of a stable moist wound healing microenvironment. The patch also sustained the release of LA, providing antioxidant and antibacterial activities. In a rat oral ulcer model, PolyLA/BET outperformed the commercial patch in promoting wound healing.

Dielectric elastomers (DEs) actuated via the space charge mechanism are characterized by low driving electric fields (2−10 V/μm) and geometry-dependent actuation modes. Liquid crystalline dielectric elastomers (LC-DEs) leverage shape changes induced by thermo-responsive order-disorder transitions to alter their actuation mode with temperature. However, such systems are currently limited to thermal responsiveness and exhibit only two actuation modes-a constraint that stands in stark contrast to the flexibility and diverse actuation capabilities of natural muscles. To overcome this limitation, we present an azobenzene-based liquid crystalline dielectric elastomer (A-LC-DE) capable of multimodal actuation, enabled by its dual thermo- and photo-responsive shape-changing properties. The incorporation of azobenzene moieties allows for mesogen alignment via light attenuation during photo-inhibited network formation. This facilitates programmable thermo-responsive shape changes by varying the irradiation conditions during synthesis, thereby enabling two distinct dielectric actuation modes upon heating and cooling. Furthermore, the trans-cis photoisomerization of azobenzene endows the A-LC-DE with dynamic, light-responsive shape-changing behavior. This capability allows for the creation of diverse and reconfigurable actuation modes through spatially localized irradiation. As a result, our A-LC-DE exhibits multimodal electrical actuation that can be selectively guided by external thermal and optical stimuli, promising enhanced adaptability for future soft robotic systems.

Multicolor luminescent materials have attracted considerable attention for their applications in information storage, encryption, and flexible displays. However, these materials often suffer from cumbersome synthesis and poor film-form ability. Herein, we report a facile strategy to fabricate multicolor luminescent films by doping an intramolecular charge transfer (ICT)-active aggregation-induced emission luminogen (AIEgen) into highly polar bifuran-based polyester. In combination with the ICT effect of the AIEgen, the distinct energy transfer efficiency between the polyester and the AIEgen achieves the wide-range emission color change from blue to red in the doped films. Furthermore, the AIEgen exhibits reversible pH-responsiveness and irreversible photocyclization under 365 nm UV light. Accordingly, a nine-grid and “dragon/QR code” patterns are designed using these doped films, demonstrating their potential in advanced information encryption and storage. This work not only provides a new perspective on the fabrication of multicolor luminescent materials, but also paves the way in information storage, data encryption, and other advanced technologies.

Ionic thermoelectric gels based on the Soret effect play an important role in realizing the efficient conversion of thermal and electrical energy, which is crucial for renewable energy utilization and efficient energy management. In this study, chitosan hydrogels were fabricated by complexation of chitosan and various metal ions via a freeze-casting approach for unitization as ionic thermoelectric materials. Various aggregate structures, including loosely fibrous networks, oriented porous structures, and lamellar porous structures, were obtained owing to the different interactions between chitosan and metal ions. As a result of the synergy of both the aggregate structure and intermolecular interaction, the as-prepared chitosan hydrogels demonstrated wide thermoelectric coefficient ranging from +1.6 mV·K⁻¹ to −18.4 mV·K⁻¹, which can be achieved by simply involving different metal ions. The present work not only demonstrates the correlation between gel structure, intermolecular interactions, and thermoelectric performance, but also provides a simple approach for the fabrication and regulation of natural polymer-based thermoelectric materials.

Direct ink writing (DIW) has emerged as one of the most promising approaches for biomedical application, owing to its broad material compatibility, ease of operation, and high-resolution. However, the development of DIW inks with suitable rheological properties and excellent biocompatibility remains a significant challenge. Herein, an acrylate-functionalized liquid poly(4-methyl-ε-caprolactone) (PMCLDA) was synthesized as the precursor of 3D printing ink, accompanied with thiol-functionalized polyethylene glycol (PEGSH) as a rheological modifier. It was indicated from rheology study that the incorporation of PEGSH with PMCLDA precursor afforded the mixt inks shear thinning behavior. Moreover, it was verified by in situ Fourier transform infrared spectroscopy and photo-rheology that the mixed ink could rapidly cure through thiol-acrylate crosslinking under UV light. Various inks formulations were successfully utilized for printing 3D scaffolds via UV-assisted DIW, with the optimized printability for SH75 ink. Moreover, the 3D-printed scaffolds exhibited excellent elasticity and degradability. In vitro cytocompatibility assessments showed that the scaffolds exhibited good cytocompatibility and supported the proliferation of L929 mouse fibroblasts for a duration of 7 days. Therefore, it is demonstrated that the 3D-printed scaffolds crosslinked via thiol-acrylate crosslinking have great potential for applications in tissue engineering.

In this study, the coordination pathways and decomposition behavior of azo-containing dicyano compounds within Fe(acac)₃/AlⁱBu₃/donor ternary catalyst systems were systematically investigated via in situ Raman spectroscopy. Additionally, the modulating effect of conjugated moieties on the coordination interaction between cyanide groups and Fe ions was examined in detail. Experimental results demonstrate that isoprene polymerization catalyzed by azodicyanide mediated Fe-based catalytic systems proceeds via a coordination polymerization mechanism. Notably, the azo group does not directly participate in the coordination process; instead, it exerts a regulatory influence on the coordination capacity of the cyano group. Although thermal decomposition of the azo group occurs at elevated temperatures, it fails to initiate free radical polymerization of the isoprene monomer. Conjugated moieties including azo, vinyl, and benzene rings exert distinct impacts on the cyanide group. As electron-donating species, their Raman spectral characteristics reflect varying influences on cyanide coordination behavior. Density functional theory (DFT) calculations demonstrate that AIBN with azo groups as the conjugated moiety exhibits the most negative Gibbs free energy (ΔG°=–222.71 kcal·mol^–1) for the coordination reaction with Fe²⁺, indicating that the cyano groups in the azo-containing compound possess the strongest coordination capability with Fe²⁺. The coordination effects of conjugated groups on the cyanide center follow the sequence: azo > carbon-carbon double bond > benzene ring, where azo groups show the most significant coordination enhancement. These theoretical findings are consistent with the observed polymerization activity, suggesting that rational design of electron donors can be guided by theoretical calculations.

Membrane-less organelles (MLOs), formed by liquid-liquid phase separation (LLPS) of biomolecules in cells, play crucial roles in cellular function such as gene expression, epigenetics, cellular metabolism, and so on. Moreover, the function of MLOs is closely related to the size of their droplets. Synthetic coacervates, which mimic MLOs, show great potential in cell biomimicry, drug delivery, and functioning as nanoreactors. However, the droplet size regulation of coacervates excluding concentration is challenging. In this work, synthetic coacervates are formed by poly(hydroxypropyl acrylate) (PHPA), which undergoes lower critical solution temperature (LCST)-type coacervation driven by hydrophobic interactions under physiological conditions. The size of the coacervate droplets is regulated by incorporating a more hydrophobic block, poly(di(ethylene glycol) ethyl ether acrylate) (PDEGA); the droplet size decreases from 5 μm to 234 nm as the PDEGA block length increases. Additionally, liquid-to-solid phase transition (LSPT) is observed with further increase in the PDEGA block. Thus, both droplet size and LSPT are controlled by the hydrophobicity of the block copolymers. The LCST-type coacervate shows thermal protection of enzymes such as glucose oxidase, which decreases as the size of coacervate droplets decreases, while the precipitates offer no protection activity. Furthermore, glucose oxidase (GOx) retains over 85% of its activity after 3 h of treatment at 60 °C with PHPA₄₄ coacervate. The hydrophobicity-tuned size control of coacervate droplets and LSPT bring insight into the molecular mechanism of coacervate phase change and facilitates the design of coacervate for biomimicking applications.

Polymer-based piezoelectric films can be assembled into piezoelectric nanogenerators (PENGs), which can simultaneously serve as flexible pressure sensors and energy harvesting devices. However, the low piezoelectric output of PENGs is a major limitation for their practical applications. Herein, we propose a coaxial electrospinning strategy to generate a core-shell structured nanofiber film, which could significantly enhance the piezoelectric output compared to the traditional nanofiber film via conventional single-axial electrospinning. Notably, the as-prepared PENGs based on the core-shell structured CsCuCl₃/poly(vinylidene fluoride) (PVDF) nanofiber composite film (2 wt%) produced via coaxial spinneret exhibit a 60% increase in output voltage (increase from 48 V to 75 V) and a 50% increase in short-circuit current (increase from 0.2 μA to 0.3 μA) compared to those prepared using a single-needle spinneret. More interestingly, this enhancement in piezoelectric performance is a universal phenomenon because the coaxial electrospinning process can induce greater polymer chain alignment in the shell layer and lead to increased crystallinity and a higher proportion of the piezoelectric-active β-phase. Owing to their enhanced piezoelectric output and high sensitivity to subtle pressure variations, the resulting PENGs demonstrate promising potential for human-machine interaction applications. This study offers a novel and broadly applicable approach to boost the piezoelectric performance of polymer-based PENGs.

The long-range order and intrinsic entanglement of polymer play a crucial role in crystallization and the corresponding melting relaxation which, however, are rarely treated as a form of symmetry. In this work, a field model is developed based on a self-avoiding random string with open ends, where time dimension for string vibrations is added and the dynamics of chain vibrations is captured by a $ \phi^4 $ theory with O(N) symmetry. The long-range order triggered by crystallization is referred to the scalar's breaking in grand canonical ensemble, while entanglement is considered as a geometric dynamic effect in absence of closed loops, rather than chain topology. For the entanglement, there are interactions among the replica scalar's components via the gauged O(N) symmetry. The infrared stability at $ d = 3+1 $ requires $ N = 2 $, thus the gauge-scalar theory is reduced to Coleman-Weinberg model in the rest frame. The finite-temperature effect causes the second-order phase transition related to scalar's breaking to become first-order with a metastable region, depending on the gauge coupling g. These modeling results are helpful in understanding the crystallization and melting behavior of polymer, including the difference of the extrapolated temperatures in Gibbs-Thomson equation, and the re-entanglement and the vanishing of long-range order in melt relaxation.

Recent advances in polymer synthesis have enabled the creation of block copolymers with increasingly complex chain architectures, presenting exciting opportunities for novel materials design. However, elucidating and exploring their intricate mesophase behavior calls for highly efficient computational tools. Building upon recent developments in optimizing propagator computations for branched polymers, such as dynamic programming approaches and extensions of comb polymer methods, we introduce a novel topology-driven acceleration algorithm specifically designed for graph-enhanced field-based simulations (FBS) of block copolymers. Unlike prior methods focused on specific redundancies, our approach leverages graph isomorphism for topological decomposition, enabling systematic handling of symmetries in arbitrary architectures. Comprehensive benchmark tests on diverse complex architectures, including miktoarm star polymers and dendrimers, demonstrate significant computational speed-ups across a wide range of ordered phases. The acceleration algorithm not only enables rapid exploration of vast parameter spaces for complex block copolymer systems with self-consistent field theory (SCFT) simulations but also maintains full compatibility with sampling-based field-theoretical simulations (FTS), facilitating broader applicability in computational polymer science.

Predicting stress-strain behavior is key to facilitating the design of polymer materials and their products with tailored mechanical responses. However, polyurethane elastomers (PUE) often exhibit highly nonlinear mechanical responses owing to their tunable molecular structure and the complexity of microphase separation for hard segments, which poses challenges for developing models for predicting stress-strain properties. In this study, four machine learning models were constructed to predict the stress-strain curve of PUE, mainly by investigating the influence of molecular hard segment content and molecular structure characteristics on the mechanical properties of PUE. Based on the Pearson correlation analysis, key variables were screened to effectively capture the evolution law of the mechanical behavior of PUE. The results show that the Transformer model performs the best and can effectively predict the stress-strain behavior of the PUE (coefficient of determination (R²) = 0.79, root mean square error (RMSE) = 5.82). Cross-validation was adopted to evaluate the generalization ability of the model. The experimental data further confirmed that this model can effectively fit the stress-strain curve of PUE. The Shapley additive explanation (SHAP) method was adopted to analyze the contribution of key descriptors to the stress response, and the intrinsic correlation between molecular structure characteristics and macroscopic mechanical behavior was revealed. Among them, descriptors such as SlogP_VSA10 were used as structural proxies for soft segments, whereas descriptors such as RingCount quantified the impact of hard segments. In addition, BCUT2D_CHGHI directly affects intermolecular forces (such as hydrogen bonds), which are crucial for microphase separation and the mechanical properties of elastomers. In conclusion, by using machine-learning algorithms to establish quantitative relationships between these descriptors and mechanical properties, we can adjust the molecular structures related to the descriptors to achieve PUE with customized mechanical responses.