Molecular initiating agents, particularly those used for photoinitiation, have dominated hydrogel synthesis for decades. However, their small molecular nature leads to several issues in hydrogels: migration out of the polymer matrix, poor photostability, limited functionality, and relatively poor mechanical properties. In this study, we report macromolecular examples of radical covalent organic frameworks (COFs) as next-generation photoinitiating agents for hydrogel synthesis, along with a proposed dual-initiation mechanism. In situ polymerization in radical COFs enables hydrogels with an ultrahigh tensile strength of 4.3 MPa, outstanding stretchability with a fracture strain improved by 1 order of magnitude (13,382%), an exceptional toughness of 262 MJ/m3, and fully recoverable large deformation (up to 1500% strain). This exceptional performance is attributed to the physical nanoconfined effect of the framework and chemical crosslinking between hydrogels and COF walls. Furthermore, the exceptional strength, toughness, and durability of the hydrogel enable its excellent applicability in wearable sensors, delivering multiangle detection with high sensitivity over prolonged operation.

Transparent ionically conductive self-healing polymeric materials are essential for enabling many next-generation technologies in areas including electronics and robotics. However, many of them lose their self-healing ability when they come into contact with water. Herein, starch-based, conductive, underwater-healable and transparent ionogels for soft electronics (SCUTE) are introduced. SCUTEs consist of starch macromolecules that are partially substituted with cyanoethyl groups, and incorporated with hydrophobic ionic liquid tributyl(methyl)ammonium dicyanamide. The aprotic cyanoethyl groups possess a high polarity, thereby capable of forming dipole-dipole interactions stronger than hydrogen bonding of hydroxyl groups. Despite its high polarity, the cyanoethyl groups possess hydroneutral characteristics that only interact weakly with water. This allows dipole-dipole interactions between cyanoethyl groups to be uninterrupted even in the presence of water. More importantly, the synergistic effect between the hydroneutural cyanoethyl dipole-dipole and hydrophilic hydrogen bond led to SCUTEs' distinct water-accelerated self-healing ability. In particular, healing efficiency in stretchability for SCUTE-20 increased from 37.4% in ambient to 92.0% when exposed to water, for a healing duration of 24 h. To show its potential in soft electronics, SCUTE is demonstrated as electronic skin for robotics control and 3D-printed aquatic electronics.

Covalent organic frameworks (COFs) are versatile materials platforms for precise function integration owing to their high crystallinity, large surface areas, tunable characteristics and diverse and predictable structures. However, the dominant solvothermal method for COF synthesis requires harsh conditions, including high temperatures, toxic organic solvents, sealed and pressurized reactors, and extended reaction times that often exceed several days. Here we present a probe-based sonochemical method for synthesizing COFs in an aqueous environment under ambient atmosphere, offering a safer and faster alternative. By employing sonication in an aqueous acetic acid solution, the protocol avoids harmful organic solvents and high-pressure systems and reduces the reaction times to under 1 h. COFs synthesized through this method have large surface areas and high crystallinity, making them ideal for applications in photocatalysis, gas sorption, food contaminant removal and chemical sensing. The broad applicability of this synthesis method has been demonstrated by successfully preparing 62 COFs with various linkage types, including imine-linked, β-ketoenamine-linked, azine-linked and hydrazone-linked COFs, as well as frameworks with one-dimensional, two-dimensional and three-dimensional topologies. The process (performed at the 50-100 mg scale) involves steps such as preparing monomer solutions, using sonication to induce COF formation and postsynthesis purification. The surface area is characterized using nitrogen sorption, while the crystallinity is assessed by powder X-ray diffraction and transmission electron microscopy. The entire protocol can be completed within 24 h and requires moderate expertise in materials chemistry and access to standard laboratory equipment.

Developing polymer composites that simultaneously achieve high strength, toughness, and impact resistance remains a fundamental challenge due to inherent trade-offs and brittle interfacial failure. Here, we propose a universal toughening strategy that integrates a bone-inspired trabecular interlock architecture with a thermodynamically driven, stress-adaptive interface to enable efficient energy dissipation under mechanical loading. To address multi-objective optimization in composites design, we further develop a data-driven framework combining Pareto Set Learning and Active Learning, which systematically explores the composition-performance landscape to identify balanced, high-performance formulations. The optimized composites exhibit synergistic mechanical properties: strength up to 250 MPa, fracture toughness exceeding 14 MPa·m1/2, and impact resistance of nearly 4.8 J, surpassing most bioinspired and engineered polymer counterparts. The strategy is scalable, chemically versatile, and broadly applicable, offering a programmable route to next-generation lightweight composites for aerospace, transportation, and protection.

Delivering nanocomposites that combine high strength, toughness, and multifunctionality remains a major challenge, as conventional trial-and-error and design-of-experiments approaches cannot efficiently resolve trade-offs in high-dimensional design spaces. We introduce a machine-learning-assisted bio-interfacial design framework integrating Gaussian-process surrogates, Pareto set learning, and active learning to explore composition-processing spaces under calibrated uncertainty. The workflow converges after nearly 60 experiments, reducing experimental count, project duration, and cost by 74%-85% relative to conventional methods, thereby accelerating design cycles and expanding Pareto coverage. Guided by this approach, we realize mycelium-graphene composites with strength >58 MPa, toughness >6 MJ/m3, and levitation >0.14 mm, showing that strength can be maintained while toughness is significantly enhanced and multifunctionality unlocked. Mechanistic analyses reveal nanosheet-pinned, hierarchically entangled interfaces where hydrogen-bonded junctions enable reversible nanosheet sliding, crack deflection, and adaptive stress transfer. These architectures impart levitation control, laser-driven actuation, and self-healing. Extension to MXene systems yields composites with enhanced resilience and electromagnetic interference shielding above 40 dB, confirming the generality of the strategy. Together, these advances define a scalable and sustainable paradigm for the accelerated discovery of robust, multifunctional nanocomposites.

ABSTRACT Polymers prepared by inverse vulcanization have demonstrated overwhelming superiority over traditional organic materials for application as infrared optical materials. It is however still a great challenge to achieve suitable refractive index ( n ) and infrared transparency for all‐organic polymers, in contrast to inorganic optical materials. Herein, poly(S‐TTF) polymers with controlled sulfur feeding ratio were constructed by inverse vulcanizing tetrathiafulvalene (TTF, a very sulfur‐rich monomer). The resulting poly(S‐TTF) possessed large polarizability, multiple reaction sites, and high symmetry that endow the polymers with increased infrared refraction and transmission. Together with remarkable stability, lightweight and good processability in imprint lithography, the poly(S60‐TTF) with 88wt% sulfur content exhibits a competitive and tunable refractive index (∼3.0) and transmittances of >60% in near and mid‐infrared regions by a millimeter‐level optical window. An ideal transmittance of visible light ( T Vis < 2%) and near infrared ( T NIR > 90%) was also realized for poly(S60‐TTF) films with 5µm thickness. Our strategy not only yields organic copolymers with competitive refractive index and exclusive infrared transmittance over inorganic materials for imaging and security applications, but also provides a valuable reference for balancing optical properties of inversed‐vulcanized polymers using sulfur‐ultrarich monomers.

ABSTRACT Hydrogels are widely applied in various fields, including energy storage and flexible electronics. However, their mechanical properties often fail to meet the requirements for long‐term and repeated deformation and full recovery. Achieving simultaneous improvement in the strength, toughness, and elasticity of hydrogels remains a significant challenge. Here, we report a nanoconfined polymerization strategy within the well‐designed, fully delaminated nanoscale covalent organic frameworks (nCOFs) that overcomes these trade‐offs. This approach yields hydrogels with an order increase in strength (from 0.3 to 3.2 MPa), a two orders enhancement in toughness (from 7.5 to 186 MJ/m3) and fracture energy (from 0.8 to 14.7 kJ m−2), and a very low‐hysteresis (∼93% energy recovery) recoverable deformation even after 2000% strain in the 100 cycles. The dense entanglements provide high strength and toughness, and nanochannel‐threaded crosslinking enables large elastic deformation. Furthermore, their robust architecture affords a fivefold improvement in puncture resistance, enabling application as dendrite‐inhibiting and durable quasi‐solid‐state Zn‐ion electrolytes. This bottom‐up toughening strategy based on the nano‐reactor nCOF structural design could guide the development of next‐generation tough hydrogels for applications such as flexible energy devices and related fields.

Simultaneously achieving high visible transparency, high refractive index (n), and a large Abbe number (υD) in organic polymers remains a fundamental challenge. Here, a facile and efficient dual sulfur-mediated Michael addition strategy is reported to synthesize transparent high refractive index polymers (HRIPs) with large υD. By combining main backbone de-conjugation to preserve visible transparency with rational side-chain engineering for n-tuning, the optimal polymer (H4) achieves an ultrahigh n of 1.86 at 589 nm alongside a large υD of 34.93 and robust stability. Moreover, polymer H4 exhibits remarkable performance in nanoimprint lithography, replicating features down to 75 nm with aspect ratios up to 8.5 and a low volumetric shrinkage of only 3.23%. Notably, a nanoimprinted metalens prototype fabricated from H4 delivers a relative focusing efficiency of 49.8% at 550 nm (NA = 0.5), approaching the theoretical design value (52.94%). Therefore, the high refractive index polymer H4 bridges molecular design and manufacturable meta-optics, showing tremendous potential in scalable, flexible, next-generation photonic platforms by translating side-chain polarizability engineering into practical wavefront control.

Water is generally considered a plasticizer that weakens polymer mechanical properties. Here, we show that in polyacrylamide (PAM), water plays distinct roles depending on its state in the polymer matrix: free water plasticizes PAM into a soft gel, whereas bound water forms strong PAM-water-PAM hydrogen-bond networks that surpass direct PAM-PAM interactions, enabling ultra-strong PAM. Confined bound water reinforces the polymer matrix, increasing the tensile modulus from ∼0.6 to 9.2 GPa and the tensile strength from 2.7 to 140 MPa, while also yielding record-high flexural (197 MPa) and compressive (178 MPa) strengths. Molecular dynamics simulations indicate that bound water organizes into linear nanoclusters that dynamically couple polymer chains, maximizing interchain cohesion and enabling efficient energy dissipation under stress. The resulting material surpasses many high-performance polymers, including polyamide-imide (PAI), polyether ether ketone (PEEK), and polyimide (PI), and exhibits exceptional flame resistance (limiting oxygen index ∼46). These findings establish bound water as an intrinsic structural enhancer, redefining its role in polymer reinforcement and providing a new design strategy for high-performance synthetic polymers.

The growing demands of integrated electronic devices for multifunctional materials have driven the development of highly conductive organic composites. Among them, carbon nanotubes (CNTs)/polyaniline (PANI) have attracted extensive attention with significant progress. However, the inferior dispersibility of CNTs remains a critical challenge that hinders further improvement in electrical conductivity. Herein, we successfully develop a highly conductive CNTs/PANI film (6126 ± 166 S cm-1) through the optimization of CNTs dispersibility. The uniformly dispersed CNTs, conductive bridge of PANI, and π-π conjugated interactions between PANI and CNTs facilitate the formation of an interconnected conductive network, which enables efficient carrier transport and endows the composite with remarkable electrical conductivity. As a result, the composite achieves a high electromagnetic interference shielding effectiveness of 60.9 dB at a thickness of 30 μm. Subsequently, a facile alkali treatment is employed to partially dedope the CNTs/PANI films, compromising the trade-off between electrical conductivity and Seebeck coefficient. After 1 min of alkali treatment with 0.01 M NaOH, an optimal power factor of 365.6 ± 26.5 μW m-1 K-2 is achieved. Furthermore, a thermoelectric device comprising of CNTs/PANI composite films demonstrates high output power, prominent sensing capability, and exceptional signal encoding ability. These findings underscore the multifunctional application prospects of CNTs/PANI films in next-generation smart electronics.

Photocatalytic hydrogen peroxide (H2O2) production offers a sustainable route for on-demand generation. Covalent organic frameworks (COFs) are attractive candidates, as their modular architectures can be engineered for optimal light capture and charge separation. However, their practical use has been hindered by the limited chemical stability of imine-linked COFs under prolonged operation. This challenge is further compounded by the narrow selection of building blocks suitable for efficient H2O2 generation, restricting advancements in catalytic performance. Here, we present two polyimide-based COFs (NUS-76 and NUS-77) constructed with a newly designed fused-ring triphenylene building block, enabling efficient photocatalytic H2O2 production. Utilizing a simple water-assisted microwave synthesis, both COFs exhibit remarkable robustness, retaining their crystalline structure even in strongly acidic and alkaline environments, outperforming the established imine-linked COF. Remarkably, NUS-77 integrates triphenylene and oligo(phenylenevinylene) moieties, delivering an impressive photocatalytic H2O2 evolution rate up to 23,284 μmol g-1 h-1. To further showcase their practical potential, we developed a continuous-flow photoreactor incorporating NUS-77, which produces 40.7 mM H2O2 in 9 h and retains activity over four consecutive cycles (36 h) under 1 sun irradiation (P = 100 mW cm-2), a product concentration exceeding that of most reported COF photocatalysts. Theoretical calculations reveal that the imide linkage enhances charge separation and facilitates the formation of ·O2- intermediates during the catalytic redox cycle. Together, these findings illustrate how strategic engineering of linkages and building blocks effectively overcomes the stability limitations of COF-based photocatalysts, providing a viable pathway to durable frameworks for solar-to-chemical energy conversion.

ABSTRACT Ionic thermoelectric (i‐TE) materials have attracted considerable interest due to their abilities to generate high thermovoltage for low‐grade waste heat harvesting. However, challenge still remains to develop high‐performance i‐TE materials, especially at relative low humidity (RH) range <60%. Herein, i‐TE ionogels based on cross‐linked Pluronic block copolymer (PEO x ‐PPO y ‐PEO x ) diacrylate and ionic liquid with simultaneously enhanced ionic conductivity and ionic Seebeck coefficient were developed. Benefiting from the amphiphilic nature of Pluronic block copolymers, self‐assembled micelles spontaneously form in ionogels, leading to a controllable nanophase‐separated micellar structure, while crosslinking suppresses PEO crystallization. This unique structure promotes continuous ion‐transport pathways and leads to high ionic conductivity. In addition, the intermolecular interactions between ions and block copolymer backbones could be tuned by different PO block ratios in Pluronic block copolymers. Consequently, the Pluronic P123DA ionogel exhibited an exceptional σ i of 4.29 S m −1 , S i of 18.2 mV K −1 and corresponding PF of 1422.4 µW m −1 K −2 and ZT i of 1.89 at RH of 55%. This design of amphiphilic Pluronic‐DA ionogels provides a versatile strategy for high‐performance i‐TE ionogels for promising low‐humidity low‐grade heat harvesting applications.

Polyethylene (PE) and polyamide 6 (PA6) are critical liner materials for high-pressure hydrogen storage, yet the coupling between triaxial stress and hydrogen (H2) diffusion and permeability remains poorly quantified. Using molecular dynamics simulations, we investigate microstructural evolution and H2 transport kinetics of amorphous PE and PA6 under anisotropic triaxial loading. Our results reveal a fundamental divergence in material response: under applied stress, PE develops strongly aligned-chain domains, characterized by pronounced backbone orientation and local densification. In contrast, the rigid H-bonding network of PA6 suppresses chain reorganization, maintaining a stable amorphous state. We find that H2 diffusion in PE is inversely correlated with the degree of chain alignment, with highly aligned-chain domains acting as effective barriers that substantially reduce the diffusion coefficient. The primary contribution of this work is the identification of a dynamic tortuous path inhibition, where local phase transitions under service-level stresses actively modulate H2 permeability. These findings provide a theoretical framework for designing smart polymer liners that utilize operational mechanical loads to enhance their own barrier performance.

4D printing of shape memory polymers (SMPs) allows the 3D-printed structures to have adjustable shapes, properties, and functionalities, paving the way for intelligent devices and multifunctional applications. However, 4D-printed SMPs face challenges due to mechanical anisotropy and mediocre shape memory performance hampered by weak interlayer adhesion. This study innovatively integrates shape memory polyamide elastomer with 4D printing technology to develop a multifunctional intelligent orthosis. Here, a dynamic bonds (DBs) reinforced shape memory polyamide elastomer is developed using a twin-screw extruder through reactive extrusion. Dynamic covalent networks are introduced into polyamide elastomer, which enhances interlayer adhesion in 4D-printed objects by utilizing combined effects of multiple dynamic covalent bonds (DCBs) and hierarchical hydrogen bonds (DHBs), leading to the reduction of mechanical anisotropy and improvement of the mechanical and shape memory properties of the 4D printouts. 4D-printed objects demonstrated excellent macroscopic shape memory and reconfiguration, showcasing the versatility of this material, and the application for spinal orthosis is also demonstrated.

Intumescent flame retardants (IFRs) are extensively used to make polymers flame resistant, and their efficacy is dependent on the synergism of the components. For polypropylene (PP), high IFR loading (normally > 25 wt%) is required for good FR performance. This sacrifices mechanical properties, processability and induces high moisture absorption and severe additive migration. Herein, we designed a novel synergist consisting of 10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide segments-grafted nitrogen-rich chains. The synergist was combined with a base FR (ammonium polyphosphate, APP) to create a novel binary IFR. With a synergist/APP ratio of 1/3 similar to 1/4, the IFR achieved UL94 V0 and V2 rating in PP at lower loading of 22 wt% and 18 wt%, respectively. This is due to: (1) improved thermal matching between PP and synergist/APP, (2) efficient synergy between synergist and APP and (3) the additional FR functions of the synergist. Simultaneously, the IFR (22 wt% loading) enhanced the tensile modulus, tensile strength and impact toughness of PP by 62.2 %, 33.8 % and 12.9 %, respectively, enhanced water resistance and reduced additive migration in PP, due to the long chain of the synergist entangling with the PP backbones. This demonstrates the effectiveness of the designed synergist in optimizing the FR performance, mechanical properties and structural stability.

Affordable, easily recycled organics with electroactive centers have drawn attention in the pursuit of highperformance aqueous zinc organic batteries (AZOBs). However, intrinsic barriers such as high solubility, undesirable potential, and inferior conductivity hinder their further development. To this end, we have designed an advanced cathode material for AZOBs, comprising an n-type polymer with a three-dimensional (3D) building block (HAT-TP) formed by polymerizing 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexazepenanthrene (HAT-CN) and 3D 2,3,6,7,14,15-hexaaminotriptycene (THA-NH2). The introduction of a 3D architecture not only bolsters the insolubility but also exposes redox-active sites for cation coordination, while the material's extended conjugated system promotes electronic delocalization to increase the redox potential and conductivity. As a result, a HAT-TP battery exhibits a notable initial discharge voltage of 1.32 V at 0.1 A g-1, followed by a midpoint voltage of 1.17 V. Remarkably, an ultrastable capacity retention ratio of up to 93.4% is achieved, even after 40,000 cycles at 5 A g-1. Theoretical simulations reveal that the elevated discharge potential results from the strong electronic delocalization of HAT-TP, which improves the affinity with cations. Ex situ characterizations and theoretical calculations verify that the reversible Zn2+/H+ co-storage mechanism involves only electroactive C=N sites and the best possible coordination paths between them.

The modification of thermoplastic polymers is frequently impeded by the inherent contradiction between their toughness and strength. In this study, an effective strategy to significantly improve the mechanical properties of ductile polymers by simply adding a complimentary rigid polymer is introduced. This work uses a semi-crystalline polymer aliphatic polyketone (POK) as the matrix material and a small quantity of polymethyl methacrylate (PMMA) as the rigid polymer, through establishing molecular chain entanglements at the interface to produce POK/PMMA blends with exceptional mechanical property. The experimental study shows that PMMA as a small island phase is homogeneously dispersed in the POK matrix, while the interfacial adhesion between the POK matrix and PMMA island is enhanced by the high-density molecular chain entanglement between PMMA and the POK matrix. The strong entanglements and high concentration of PMMA domains promote uniform crazes and overall shear yielding. As a result, the POK/PMMA blend exhibits exceptional mechanical properties with notched impact strength, elongation at break, tensile strength, and Young's modulus, of 20 kJ m-2, 326%, 60 and 2185 MPa, respectively. A universal approach is further suggested for enhancing the toughness and strength of ductile polymers using a complimentary rigid polymer.

Developing a sustainable, in-situ responsive sensing method for continuously monitoring water quality is crucial for water use and quality management globally. Conventional water quality monitoring sensors face challenges in achieving ultrafast response time and are non-recyclable. We present a self-assembly approach for a closed-loop recyclable, autonomous self-healing and transparent dielectric material with nanostructured amphiphobic surfaces (termed 'ReSURF'). Our approach uses tribo-negative small molecules that spontaneously secrete onto the surface of the fluorine dielectric matrix via biomimetic microphase separation within minutes. ReSURF devices achieve millisecond water quality sensing response time (~6 ms), high signal-to-noise ratio (~30.7 dB) and can withstand large mechanical deformations (>760%, maximum of 1000% strain). We show ReSURF can be readily closed-loop recycled for reuse, underscoring its versatility. We further demonstrated its use in a soft stretchable fish-like robot for real-time water contamination (including perfluorooctanoic acid, a member of per- and polyfluoroalkyl substances (PFAS) and oily pollutants) assessments.

Harvesting electricity with high-performance biodegradable thermoelectric (TE) composites is a sustainable and promising approach that addresses the environmental concerns brought from the conventional thermoelectric devices. In this work, a TE composite based on single-walled carbon nanotubes (SWCNT) is reported and biodegradable polycaprolactone (PCL) with significantly improved TE performance, achieving a significant improved power factor of 439 µW m-1 K-2 at 90 wt.% SWCNT loading. The good surface compatibility and interfacial interaction between PCL and SWCNT are conducive to the formation of abundant PCL-SWCNT junctions, enabling an efficient energy filtering effect that significantly enhances the Seebeck coefficient to 40.8 µV K-1 at SWCNT content of 90 wt.%. Meanwhile, minimal charge tunneling hindrance is allowed to across thin PCL layers, thereby maintaining a high electrical conductivity of 2635 S cm-1. Subsequently, a flexible TE device assembled from the SWCNT/PCL composite films exhibits a power density of 1.50 W m-2 at a temperature difference of 30.8 K, demonstrating great potential for high-performance and sustainable thermoelectric energy harvesting.

Hydrogels and elastomers are integral components in biomedical and electronics devices, but their toughness and crack resistance are often unsatisfactory for load-bearing applications. Synthetic polymer networks predominantly rely on solution fabrication, which compromises the ultimate mechanical properties. This work presents a universal melt crosslinking strategy, which densifies entanglements well beyond solvated conditions. When deformed, mutually entangled dissimilar chains stiffen the gels, while sparse crosslinks amplify fracture resistance. At water contents up to 83%, the resultant hydrogels demonstrate over 2 orders increase in mechanical properties, including moduli (1.3-35 MPa), toughness (0.7-24.5 kJ/m2), and fatigue thresholds (1.2-3.3 kJ/m2), tunable in a wide range beyond existing hydrogels. Furthermore, the hydrogels show high optical clarity (>96%), oxygen permeability (Dk/t > 40), and anti-fouling properties (<0.6 µg cm-2). This generalizable strategy could guide the design of tough functional soft materials in fields such as healthcare and smart electronics.