With the rapid advancement of 5G communication and high-end chip technologies, thermal management in electronic devices has become increasingly critical. Highly filled thermally conductive polymer composites are considered promising candidates for efficient heat dissipation, yet their development has long been hindered by challenges such as poor processability due to high filler loading, weak interfacial adhesion, and lack of recyclability. Based on Diels-Alder (DA) reversible covalent chemistry, this study constructed a covalent adaptive composite network featuring a reversibly cross-linked matrix and dynamic interfacial bonding. Using a DA-cross-linked unsaturated polyester as the matrix and maleimide-modified Al2O3 as the filler, DA bonding between the filler and matrix was achieved, thereby improving interfacial compatibility. The results showed that the composite maintained good fluidity even at a high filler loading of 70 wt% (balanced torque=2.77 N & centerdot;m,120 degrees C), which wassignificantly lower than that of the covalently cross-linked control sample. The interfacial DA bonding reducedfiller agglomeration and enhanced stress transfer, resulting in a tensile strength improvement of 38% to 149% compared with reference systems. The composite also exhibited high thermal conductivity (1.50 W & centerdot;m(-1)& centerdot;K-1), self-healing efficiency (93.2%), and recyclability. This research provides a new approach for developing easily processable, recyclable, and highly filled thermal conductive composites

Self-healing represents the next generation of technology, which helps to greatly improve important performance of products, including, but not limited to, reliability and durability. This chapter presents an effort of imparting self-healing capability to woven glass/epoxy composites through embedded healing microcapsules. The healing agent consists of epoxy as the polymerizable component and mercaptan or imidazole as the hardener. Upon damaging of the composite materials, the capsules are broken, releasing healing agent, which is delivered to the cracked portions due to capillary effect and then polymerized to rebond the cracks. The results of compression after impact and other characterization techniques show that the damages inside the composites can thus be self-healed at room temperature or elevated temperature by tuning the recipe of healing agent, depending on the application requirements.

The development of advanced thermal management materials is crucial for next-generation electronics. While liquid crystal epoxy resins (LCERs) can achieve enhanced thermal conductivity through molecular ordering, their performance remains constrained by limited intrinsic conductivity and high interfacial thermal resistance when incorporating conductive fillers. Moreover, conventional thermosetting epoxies lack recyclability, posing environmental concerns. In this work, a series of imine-based LCERs with tailored molecular conformations, including varied bridging groups (ether or ester) and flexible spacer lengths, were synthesized and cured using imidazole to preserve the mesogenic order. The resulting LCERs exhibit highly oriented structures, showing intrinsic in-plane and out-of-plane thermal conductivities up to 2.54 and 0.40 W m- 1 K-1, respectively. When blended with unmodified boron nitride (BN), the composites achieve a remarkable 211.8% increase in out-ofplane thermal conductivity over pure LCERs. Systematic characterization confirms that strong Lewis acid-base interaction between BN and ester-containing LCERs facilitate interfacial phonon transport. Moreover, the linear molecular conformation of ester-bridged liquid crystal monomer promotes dense molecular packing and reduces interfacial layer thickness. Owing to the dynamic reversibility and acid sensitivity of imine bonds, the resulting composites also gain excellent capabilities for recycling and controlled degradation. This work highlights the essential role of molecular architecture in minimizing interfacial thermal resistance and offers a strategic pathway for designing highly thermally conductive polymer composites with excellent recyclability.

Structural adhesives that combine robust adhesion, low modulus, and high damping are highly desired for aerospace, automotive, and electronics applications. However, integrating these three inherently contradictory properties into a single material remains challenging due to their competing underlying mechanisms. Herein, a reversible interlocked macromolecular network (RILN) adhesive is designed through a performance-decoupling strategy: (i) a carboxyl-functionalized polyurethane (BPU) with boronic ester bonds that provides adhesion groups and dense cross-linking, ensuring strong interfacial bonding and cohesive strength; (ii) a low-modulus polyurethane (SPU) containing disulfide bonds, dangling chains, and loose cross-links that acts as an internal plasticizer to regulate modulus; and (iii) an integrated RILN structure in which extensive inter-network chain slippage enables efficient energy dissipation and high damping. The resulting adhesive exhibits high adhesion strength (9.94 MPa), low modulus (<1000 MPa), superior toughness (57.46 MJ m-3) and consistently high damping across multiple dynamic loading modes. It also demonstrates excellent low-temperature tolerance, superior self-healing capability, detachability, and recyclability. This RILN design strategy offers a broadly applicable approach to developing adaptive structural adhesives that reconcile multiple competing properties for advanced engineering applications.

Reversibly crosslinked polymers (RCPs) combine the structural stability of thermosets with the reprocessability of thermoplastics, yet their potential for achieving ordered orientations remains underexplored. This review systematically summarizes recent advances in the alignment of molecular chains, structural units, and functional fillers in RCPs and their composites through stimulus-assisted drawing techniques, focusing on three key effects of orientation: self-reinforcement of mechanical properties, improvement in processability (e.g., spinnability of crosslinked fibers, multidomain-monodomain transformation of liquid crystal elastomers), and assisted orderly arrangement of functional fillers. By elucidating the mechanisms through which dynamic reversible bonds facilitate network reorganization under external stimuli, this review highlight strategies for achieving controlled structural evolution. The findings demonstrate that RCPs offer a versatile platform for designing high-performance materials with tailored anisotropy and functionality. However, challenges such as limited utilization of diverse reversible bonds, insufficient control in composite filler alignment, and a lack of theoretical processing frameworks remain. This review concludes with perspectives on future research directions to overcome these barriers and advance functional RCP-based materials.

To suppress phase separation and improve fluorophore dispersion in physically blended white-light-emitting polymer materials, while also achieving stretchability and repairability, reversibly interlocked macromolecular networks (RILNs) are employed in this work. A stretchable, self-healable, and robust RILNs-based white-light material with adjustable multi-color fluorescence is synthesized from a Schiff base bond crosslinked single network containing red-light-emitting and green-light-emitting groups and a boronic ester bond crosslinked epoxy network carrying blue-light-emitting side chains. The interlocking network's phase separation suppression effect reduces aggregation-induced quenching of the incorporated luminophores, thereby improving white-light regulation convenience and achieving an ultra-high white-light quantum yield of 58.1% for polymer-based materials (photoluminescence luminance = 359 cd m-2 under 420 nm excitation). The resulting materials also show good mechanical properties (tensile strength = 5.5 MPa, elongation at break = 78.5%), stretchability, fatigue resistance, self-healability and recyclability. Benefited from the reversible exchange reactions of built-in reversible covalent bonds at moderate temperature, the mechanical and optical properties of the recycled materials remain nearly unchanged. The design provides a specific strategy for constructing multifunctional polymer white-light materials, with the potential to expand their scope and applications.

To gain a profound understanding of the interfacial heat transport mechanisms in hexagonal boron nitride (hBN)/liquid crystal epoxy (LCE) composites, the theoretical simulation and experimental validation approaches are combined for clarifying the relationship between interfacial microstructure, interfacial thermal resistance (ITR) and macroscopic thermal conductivities of the h-BN/LCE composites. Molecular dynamics simulations (MD) show that LCE molecules can be closely packed on the h-BN surface to lower the ITR by 21 %similar to 42 %, in comparation to that of amorphous epoxy. Afterwards, the interfacial interactions between h-BN and LCE, and the interface phase thickness (2.305 nm) are experimentally confirmed. Meantime, the reduced ITR are examined to be 15 similar to 65 % via laser flash method. The produced h-BN/linear LCE composites containing 95 wt% h-BN platelets exhibit excellent in-plane and through plane thermal conductivities up to 77.01 and 12.67 W m(-1) K-1, which exceed 25.8 % and 55.8 % those of the amorphous epoxy composite. It proves that the mesogens adsorbed on h-BN surface provides a straightforward approach to reduce ITR and enhance thermal conductivities of resultant composites. Besides, non-covalent and covalent modifications of h-BN allow to further diminish the ITR and facilitate heat transfer. The outcomes are believed to promote the application of h-BN/LCE composites in thermal management materials.

With the miniaturization and high-frequency development of electronic devices, polymer-based composites with high thermal conductivity and excellent mechanical properties have become a research priority in thermal management. Hexagonal boron nitride (h-BN), with its layered structure and ultrahigh in-plane thermal conductivity, is considered an ideal filler; however, its agglomeration and poor interface compatibility severely limit its practical applications. This study proposed a synergistic exfoliation-adsorption strategy to fabricate h-BN/LC epoxy composites via in situ ball milling, aiming to enhance the aspect ratio, specific surface area, and interfacial compatibility of h-BN. The experimental results demonstrated that ball-milling exfoliation significantlyenhanced the aspect ratio and specific surface area of h-BN, improving its dispersion and promoting the ordered adsorption of liquid crystal molecules. At 20 wt% h-BN loading, the composites achieved in-plane and through-plane thermal conductivities of 7.30 and 1.64 Wm(-1)K(-1), representing 22.7% and 82.2% improvements over conventional blended samples, respectively. Molecular dynamics simulations and finite element analysis further revealed the enhancement mechanisms: at low filler content, exfoliation amplified interfacial adsorption and constructs thermal pathways by increasing the surface area and aspect ratio, whereas spontaneous h-BN stacking at high content diminished these benefits. Additionally, the strengthened interfacial interactions endowed the ball-milled composites with superior flexural strength and modulus at 20 wt% loading. This study provides theoretical guidance for developing h-BN/LC epoxy composites with high thermal conductivity and mechanical strength

Reversibly interlocked polymer networks (RILNs) have emerged as a versatile platform technology for the development of advanced functional materials. This is achieved by integrating two chemically independent subnetworks through supposition and cooperation principles. However, their physical image and the structure-property relationships remain unclear due to the undisclosed distribution of the subnetworks. In this study, a specially designed RILN system is synthesized, where the two component subnetworks exhibit distinct microstructures in their single network states. Moreover, one subnetwork is labeled with deuterons. The microstructures of the subnetworks in the interlocked state are examined using small-angle neutron scattering experiments based on the contrast-matching method. The deuterated subnetwork, which is homogeneous prior to interlocking, displays a heterogeneous microstructure in the RILNs like the nondeuterated subnetwork. Conversely, the nondeuterated subnetwork, which exhibits segmental aggregation before joining the RILNs, becomes homogenized in the interlocked state. These findings demonstrate the convergence of microstructures of the subnetworks, contributing to a better understanding of the physical image of the RILNs and enhancing our comprehension of their structure-property relationships.

Antifouling coatings, which have important value for submerged marine structures, are faced with the challenge of inherent conflicting property requirements, i.e. the topcoat is desirable to prevent adherence of marine organisms and the basecoat should be able to maximize bonding to the substrate. Besides, the existing antifouling coatings have other tricky problems, like easy depletion of liquid lubricant of slippery liquid-infused porous surface and poor static microbes resistance of hydrophobic surface. Herein, a facile solution is proposed using the newly developed reversibly interlocked polymer networks, which enables temporally and spatially controllable multiple antifouling actions. Aided by dynamic covalent chemistry, the immiscible crosslinked polymers carrying various components with unique functionalities are uniformly interweaved producing a novel non-sticky/sticky antifouling composite coating (NSCC). Consequently, a series of non-contact and contact antifouling strategies based on physical and chemical interactions are seamlessly combined with high cohesion and interfacial adhesion. Either the surface or the subsurface of the NSCC exhibits excellent resistance to protein and bacteria under both static and dynamic conditions. The properties of the NSCC comprehensively outperform those of the analogues reported in the literatures. From a practical perspective, the redundancy design has set up a novel paradigm for preparing long-lasting antifouling coating.

Epoxy resin, traditionally used as the insulating substrate in copper clad laminates, exhibits relatively low thermal conductivity, which has emerged as a critical factor impeding effective heat dissipation. In this work, a two-step silk print approach was employed to fabricate hexagonal boron nitride (h-BN)/liquid crystal epoxy resin (LCER) composites with high thermal conductivity. Firstly, the non-patterned matrix was printed using a coating solution composed of LCER and lower content of (3-aminopropyl)triethoxysilane-modified h-BN sheets (h-BN@KH550, 10 wt%-30 wt%), followed by the filling of patterned regions (dots, lines and grids) with a LCER coating solution containing high content of h-BN@KH550 (60 wt%-80 wt%). By making use of the synergistic interactions among the h-BN@KH550 within patterned array and matrix, efficient through-plane and in-plane heat conduction pathways were successfully constructed. In addition, the influence of patterning parameters on material properties was explored. The resultant h-BN@KH550/LCER patterned composites containing 26.36 wt% h-BN@KH550 exhibited through-plane and in-plane thermal conductivities of 11.5 and 20.5 W/(mK), respectively. Furthermore, the through-plane and in-plane thermal conductivities can even reach 26.0 and 36.6 W/(mK) at a h-BN@KH550 content of 41.52 wt%, which are 10.8 and 11.8 times those of boron nitride/LCER blend composites with identical weight ratio of h-BN@KH550 sheets. [GRAPHICS] .

Customized solid-state lithium metal batteries (SSLMBs) with high safety hold promise for next-generation energy storage systems, yet they suffer from rapid capacity decay due to unstable solid-solid interfaces and uneven Li+ transport. To break the bottleneck, an in situ 3D-printed integrated porous cathode/composite polymer electrolyte (CPE) is developed using reversible Diels-Alder (DA) covalent chemistry. Typically, the reversible crosslinked CPE are produced from a furan-functionalized polyethylene glycol oligomer, tris-(2-maleimidoethyl)amine, and maleimide-modified Li6.4La3Zr1.4Ta0.6O12. During the thermal printing of CPE, its viscosity significantly decreases due to the dissociation of DA bonds in polymeric matrix and the ceramic particle/polymer interfaces, allowing the CPE to diffuse into the pre-printed porous cathode and form a continuous Li+ transport network. Upon cooling, the DA crosslinkages reform to create a robustly adaptive interface layer with low impedance and uniform Li deposition during battery operation. The resulting integrated system achieves remarkable cycling stability in SSLMBs, with 30 000 cycles at 10 C in LiFePO4||Li cells and stable Li plating/stripping over 4150 h in symmetric cells. Moreover, the 3D printing technique enables the fabrication of customized batteries and integrated functional devices that maintain stable operation under mechanical deformation, showing potential for wearable and flexible electronics applications.

Achieving repeatable self-healing without human intervention in metal circuits remains a critical challenge. Here, we repurpose electrochemical migration, typically a reliability hazard, into a controlled mechanism for intrinsic conductive self-healing. By optimizing structure of flexible printed circuit boards (PCBs), directional electrochemical migration is allowed to bridge mechanically damaged traces self-driven by the operational voltage of the PCB itself. The PCBs comprises a healable supramolecular substrate (consists of linear polyurethane and hyperbranched oligomer (LPU/HBO)), Ag circuits, a polyvinyl alcohol isolation layer, gelatin/glycerol/KNO3 colloidal electrolyte, and an LPU/HBO encapsulation layer. Upon damage, capillary action drives the electrolyte infiltration into cracks, and then promote electrochemical migration between severed wires under working voltage, autonomously reconnecting fractures via metallic dendrite growth. The self-healing procedure is repeatable, restoring approximate to 100% current in several hours at room temperature, while metal trace can withstand up to 350,000 bending cycles. This work transforms electrochemical migration from a failure mode into a sustainable self-healing strategy, advancing flexible electronics toward long-term reliability.

To tackle the challenge of producing highly filled polymer composites using the traditional injection molding technique, which is characterized by the fairly high melt viscosity that makes mold filling difficult, the authors propose a solution based on dynamic covalent chemistry. As demonstrated by the proof-of-concept experiments, the 4-arm star-shaped polycaprolactone (PCL) oligomers and microcrystalline cellulose (MCC) are crosslinked by the reversible Diels-Alder (DA) bonds. The flowability of the compounds greatly decreases due to the dissociation of the intercomponent DA bonds at the retro-reaction tempera-ture, and the networked architecture is reconstructed during cooling as a result of the forward DA reac-tion. Consequently, the high-loading MCC fillers are well distributed in the matrix and covalently bonded to the nearby PCL, forming a striking contrast to the control in which linear PCL acts as the matrix. The DA bonds crosslinked biodegradable PCL composites exhibit decent mechanical strength (20.7 MPa) even at the MCC fraction of 65 wt%, which is superior to those (5-12.2 MPa) of the highly filled PCL composites (with filler contents of 50-63.8 wt%) reported so far. The proposed approach has sufficient expansibility for the fabrication of the highly filled polymer composites constructed by other types of matrix and fillers.& COPY; 2023 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

AbstractSunlight‐triggered self‐healing of polymers has attractive advantages, but the same illumination inevitably causes photoaging. The resulting properties deterioration and shortened lifespan run counter to the desire for self‐healing. Herein, the authors propose an innovative solution by introducing carbazolyl‐based dithiocarbamate units. The proof‐of‐concept crosslinked poly(carbazolyl dithiocarbamates‐urethane) shows that the multitasking reactivities of the dynamic bonds stimulated by the sun's ultraviolet rays concurrently implement self‐healing and improve the photoaging resistance. As reflected by the xenon weatherometer measurements, it retains 73.5% of the original strength after 576 h owing to the effects of hydroperoxide intermediates elimination and fluorescence emission. The anti‐photoaging ability is far superior to the control filled with commercial stabilizer. Meantime, networks rearrangement via dynamic exchange reactions among the sunlight‐sensitive dithiocarbamates and long‐range free radicals transfer are allowed in surface layer and the interior, so that the cracks up to 8.5 mm deep are repaired. The work provides a feasible way to break the bottleneck in application of photochemical self‐healing polymers.

光照可以触发光化学自修复高分子所含光敏基团的光化学反应,从而促进大分子链的扩散、渗透和缠结,并在裂纹面间重建新的化学键,实现损伤修复,在智能涂层、光学材料和器件、软体光致动器、可穿戴柔性电子等领域具有广阔的应用前景.光作为一种清洁能源,环境友好且廉价易得,而且具有高时空分辨率,能方便地进行时间和空间维度的控制,有助于远程激活和局部区域自修复.本文从光化学反应的类型出发,即光可逆环加成反应、光致异构化反应、动态可逆交换反应和解离-结合平衡反应,综述了含不同光敏单元自修复高分子的结构特征、修复机制和研究进展,并在此基础上进一步分析了该新兴领域的挑战和发展趋势.

Corrosion of steel in the marine environment greatly reduces their service life. Polymeric coatings are the most popular anticorrosion technology, but seawater penetration cannot be prohibited because of the distinct stacking structure of the macromolecular chains. In this context, a novel anticorrosive hyperbranched polyurethane-based coating with dopamine (DOPA) at the terminals is prepared herein. The built-in DOPA is able to capture the iron ions released from the corroded substrate and form DOPA-Fe3+ complexation, which further cooperates with the surrounding seawater and imparts self-passivation, self-delivery and self-healing capabilities to the coating. Under the joint action of these measures, the corrosion of tinplate (serving as the steel model) is reduced to a record-low level (corrosion current = 1 × 10-9 A cm-2, corrosion rate = 1 × 10-5 mm year-1). Conceptually, the present dynamic active anticorrosion strategy greatly outperforms the traditional static passive approach, and turns the unfavorable but unavoidable seawater into a favorable factor, which paves the way for the development of long-lasting marine coatings.

To simultaneously endow thermal conductivity, high glass transition temperature (Tg) and healing capability to glass fiber/epoxy (GFREP) composite, dynamic crosslinked epoxy resin bearing reversible β-hydroxyl ester bonds was reinforced with boron nitride nanosheets modified glass fiber cloth (GFC@BNNSs). The in-plane heat conduction paths were constructed by electrostatic self-assembly of polyacrylic acid treated GFC and polyethyleneimine decorated BNNSs. Then, the GFC@BNNSs were impregnated with the mixture of lower concentration (3-glycidyloxypropyl) trimethoxysilane grafted BN micron sheets, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate and hexahydro-4-methylphthalic anhydride, which accounted for establishing the through-plane heat transport pathways and avoiding serious deterioration of mechanical performances. The resultant GFREP composite containing less boron nitride particles (17.6 wt

To impart processability and practical serviceability to organic room temperature phosphorescence (RTP) molecules, and address phase separation and rigid confinement environment of conventional RTP polymers, a small amount of Schiff base bonds crosslinked tetraphenylene luminescence networks are pinned to the borate ester bonds crosslinked epoxy networks producing reversible interlocked polymer networks-based halogen-free RTP material. By taking advantage of the conjugation interaction of Schiff base linkages, and phase separation inhibition/molecular confinement effects of the interlocking networks, excellent fluorescence quantum yield (up to 78.9 %), RTP lifetime (660 ms) and quantum yield (16.7 %) are achieved with ultra-low concentration of luminophores (0.05 wt%). Moreover, the resultant acquires decent tensile strength (3.8 MPa) and a high elongation-at-break (365 %) owing to its unique molecular design. The phosphorescence lifetimes (457 similar to 602 ms) are only slightly affected even after cyclic stretching (at 50 % strain for 100 cycles), or soaking in water (for 30 days), or heating (90 degrees C). The built-in reversible covalent bonds and the topological network reorganization further enable injection molding and self-healing of the material. Having been repeatedly crushed/hot-pressed, the recycled material still shows RTP lifetime and quantum yield of 398 ms and 14.6 %, respectively. The present work provides a feasible approach to fabricate multifunctional robust organic phosphorescent materials with application prospects.

For breaking through the limitation of metal patterning in constructing conductive pathways of electronic devices, which is proposed to be an upgrade of traditional etching technique, a photo-reversible, transparent and soluble polyimide carrying spiropyran side chains is synthesized. The merocyanine isomers produced from the spiropyran moieties under digitalized ultraviolet irradiation bind the silver−histidine complexes in water, while the absorbed silver ions are in-situ reduced into metal silver seeds by the photo-generated radicals from histidine molecules, catalyzing copper deposition and yielding the desired copper patterns. Accordingly, the conventional time-consuming steps (like surface modification, immobilization of catalytic ions and (photo)chemical reduction) are simplified to a single one, and the environmentally unfriendly solvent and costly/toxic palladium reagent are excluded. The Cu patterns deposited on the polyimide show high resolution, electrical conductivity (1.785 × 10−6 Ω‧cm), adhesion strength (18.14 MPa) and fatigue resistance (> 2.6 million cycles of bending). Due to the absence of invasive surface treatments (e.g., surface hydrolysis and laser direct structuring), extremely low surface roughness of 7.83 nm is achieved. Besides, the developed strategy can be easily expanded to stretchable elastomer and other organic/inorganic substrates with irregular surfaces, showing promising application prospects. The solubility of the polyimide and ultraviolet/visible light triggered reversibility of the included spiropyran groups further enable repeated recycling, erasing and re-patterning.