Search

This study investigated the mechanical responses and self-healing capability of incorporating superabsorbent polymer (SAP) particles in Fibre-Reinforced Ultra-High-Performance Concrete (UHPC) mixes under repetitive flexural and sustained tensile loadings. UHPC with SAP addition of 0.3% and 0.4% of the binder ratio were studied along with a control UHPC mix. The methodology included investigating the mechanical properties of these mixes under ambient, water, and 100% of relative humidity (RH) curing conditions. In addition, the mechanical performance of ambient-, water-, and 100% RH-cured prismatic specimens (100 mm × 100 mm × 500 mm) under repeated load was studied under the same curing conditions. Prismatic specimens (75 mm × 75 mm × 500 mm) were kept under cure conditions of wet and dry cycles with applied tensile load for 28 days for the sustained tensile load. The results showed that incorporating SAP into UHPC enhances the elastic modulus, flexural strength, and tensile strength. Also, mixes with SAP have exhibited compressive strength above 120 MPa after 90 days. Furthermore, the load recovery of the prisms under repetitive flexural load and prisms under sustained tensile loading demonstrated the self-healing efficiency of SAP incorporated into the UHPC mixes higher than the control mix specimens. [ABSTRACT FROM AUTHOR]

This study developed hydrogels containing different ratios of TA using polyvinyl alcohol (PVA) and polyethyleneimine (PEI) polymers crosslinked with tannic acid (TA) for the treatment of burn wounds. Various tests, such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), swelling, moisture retention, contact angle, tensile strength, the scratch test, antibacterial activity and the in vitro drug-release test, were applied to characterize the developed hydrogels. Additionally, the hydrogels were examined for cytotoxic properties and cell viability with the WST-1 test. TA improved both the self-healing properties of the hydrogels and showed antibacterial activity, while the added gentamicin (GEN) further increased the antibacterial activities of the hydrogels. The hydrogels exhibited good hydrophilic properties and high swelling capacity, moisture retention, and excellent antibacterial activity, especially to S. aureus. In addition, the swelling and drug-release kinetics of hydrogels were investigated, and while swelling of hydrogels obeyed the pseudo-second-order modeling, the drug release occurred in a diffusion-controlled manner according to the Higuchi and Korsmeyer–Peppas models. These results show that PVA/PEI-based hydrogels have promising potential for wound dressings with increased mechanical strength, swelling, moisture retention, self-healing, and antibacterial properties. [ABSTRACT FROM AUTHOR]

Flexible perovskite photodetectors (FPDs) are promising for novel wearable devices in bionics, robotics and health care. However, their performance degradation and instability during operations remain a grand challenge. Superior flexibility and spontaneous functional repair of devices without the need for any external drive or intervention are ideal goals for FPDs. Herein, by using phenyl disulfide instead of alkyl disulfide as a crosslinking agent, disulfide bonds with lower bond energy are introduced, thus endowing the polyurethane network (SCPU) with the ability of self‐healing at room temperature. SCPU is filled to the grain boundary of perovskite film, which not only improves the crystal quality of perovskite and mechanical stability of FPD but also enables FPD to self‐heal at room temperature. As a result, the as‐prepared FPD exhibits a superior responsivity of 0.4 A W−1, a high specific detectivity of 2.5 × 1011 Jones and 2 μs fast response time in a self‐powered mode. More importantly, the FPD still retained 91% of the initial photo responsivity after 9000 times of bending upon cyclic healing. This polymer doping strategy provides an effective solution for stable operation and room‐temperature self‐healing for FPDs. [ABSTRACT FROM AUTHOR]

Given the significant role of asphaltic pavement in surface transportation systems, even minor enhancements in asphalt materials hold the potential for cost savings and reduced environmental impacts. The healing properties of asphalt have drawn interest for sustainability, yet much remains unknown about the causes and influencing factors. To leverage self‐healing for extending pavement life, understanding the mechanisms and conditions that stimulate microcrack healing is essential. This study aims to investigate the dynamic progress of microcrack closure in asphalt mastics. The time‐series evolution of crack closure led by self‐healing is tracked by neutron computed tomography, with image processing facilitating volumetric analysis over a 7 h period. The study examines the healing process in mastic samples with three different sand filler contents (10, 20, and 30%). Results show that for all the investigated samples, the healing rate declines exponentially over time, with 100% recovery not achieved after 7 h at room temperature. Filler content‐influenced healing speed and 20% sand demonstrate the best performance. Meanwhile, the healing performance varies within the 10% and 30% groups, depending on initial crack size. Additionally, the study finds that initial crack size influences healing behavior in the samples. [ABSTRACT FROM AUTHOR]

Advanced filamentary devices are crucial for developing low‐power devices to implement high‐speed logic and neuromorphic devices. Among these, HfO2‐based filamentary devices have attracted attention as viable options due to their threshold‐switching characteristics and compatibility with complementary metal‐oxide‐semiconductor (CMOS) technology. However, the unpredictability of conventional filament formation/rupture driven by an electric field challenges consistency and reliability. A paradigm shift from conventional stochastic electric field‐driven ion migration to controllable ion‐based transportation is essential to devise functional low‐power devices capable of controlling the filament process. This work introduces a magnetic field‐assisted threshold switching (MA‐TS) device, which integrates a neodymium magnet and a nickel (Ni) barrier layer to enable controlled dual field‐driven ion transportation. The dual field‐driven process combining the conventional vertical electric field‐driven ion migration with lateral magnetic field‐driven ion transportation, reveals a distinctive aspect of ion movement. The MA‐TS device achieves superior performances characterized by an ultra‐low threshold voltage (≈0 V), minimized leakage current in the off‐state, a variation‐immune hysteresis‐free characteristic, enhanced yield, and revival‐ability (i.e., self‐healing) after a failed TS operation. By overcoming the limitations of conventional filamentary devices, the MA‐TS device opens up a promising avenue for efficient and stable low‐power applications. [ABSTRACT FROM AUTHOR]

In recent years, self-healing, ultra-thin overlay has been recognized as an advanced technology and gradually applied in asphalt pavement maintenance, but its sustainability has not been well addressed quantitatively regarding practical maintenance projects. This study utilizes steel fiber as a media-induction material for self-healing, ultra-thin overlay and verifies its integrative benefits in terms of carbon emissions and economic costs from a six-year life-cycle perspective. The system framework and research boundary were developed to include the material extraction, on-site construction, later maintenance, and demolition phases. Meanwhile, carbon emissions and economic cost inventories were established through investigations of the test section of a maintenance project. The results indicated that self-healing, ultra-thin overlay could have benefits, with a reduction of 59.43% carbon emissions and 73.15% economic costs in the six-year life cycle, during which the material extraction phase generated over 50% of the carbon emissions and economic costs in self-healing, ultra-thin overlay due to the addition of steel fiber. Comparatively, the later maintenance phase caused the most environmental and financial impacts, with over half of the carbon emissions and costs. The obtained results could act as significant reference material for the sustainable maintenance implementation of asphalt pavement. [ABSTRACT FROM AUTHOR]

The development of multifunctional supramolecular nanocomposite hydrogels remains challenging. Here, the dynamic host–guest interactions involving the host molecule CB[8] and guest units were utilized to prepare Fe3O4 hybrid supramolecular nanocomposite hydrogels. The results showed that the hydrogels obtained possessed a porous structure. The CB[8]‐modified Fe3O4 (Fe3O4@CB[8]) nanoparticles served as cross‐linkers in forming the network of hydrogels. By adjusting the Fe3O4@CB[8] content, the mechanical properties of the hydrogels could be controlled. The tensile stress was measured at 160 kPa with a fracture strain of 1380%, while the compression stress was 230 kPa at 70% compression strain. The self‐healing efficiency of the hydrogels at room temperature reached 95% after 24 h. The as‐obtained hydrogels show strain sensitivity and have the potential for applications in detecting elbow and finger movements. Our supramolecular nanocomposite hydrogels exhibit multiple functions, including self‐healing, injectability, photothermal responsiveness, and conductivity, making them suitable for integration into flexible electronics. Highlights: Fe3O4@CB[8] nanoparticles serve as cross‐linkers for the nanocomposite hydrogels.CB[8] based host–guest interactions enable hydrogels to self‐heal.Fe3O4@CB[8] endow hydrogels with stretchability and photothermal responsiveness.Hydrogels exhibit injectability, NIR responsiveness, and conductive ability. [ABSTRACT FROM AUTHOR]

This study investigates the microbially induced calcium carbonate precipitation (MICP) in repair mortar, focusing on the impact of calcium precursor dosage and bacterial strain selection. C6H10CaO6·xH2O and (CH3COO)2Ca·xH2O were used as calcium precursors at dosages of 0.1, 0.25, and 0.4 M with Bacillus subtilis VEB4, Priestia megaterium TSB16, and Halobacillus halophilus MCC2188 microbes. Quantitative assessment of precipitate and optimization of precursor dosages were conducted before making mortar cube specimens of size 70.6 × 70.6 × 70.6 mm with bacterial spores and nutrients immobilized in Modified Expanded Perlite. Cracked cube specimens underwent automated wet-dry cycles of 12 h daily for 60 days to induce healing. Comparative analysis of biomortar specimens showed P. megaterium as the most effective in compressive strength recovery (up to 89.33%) and crack healing with a maximum healed crack width of 0.64 mm, followed by B. subtilis with significant CSR improvements. H. halophilus, less efficient in non-saline conditions, healed cracks up to 0.48 mm. Calcium lactate was considered the better calcium source choice for B. subtilis and P. megaterium strains, whereas calcium acetate improved MICP by H. halophilus. Microstructural analysis of healed precipitates collected from cracked cubes identified distinct morphology of MICP and the presence of polymorphs viz, calcite, aragonite, and vaterite. Tailored selection and dosage of calcium precursors for each strain significantly enhanced MICP and improved the quality of healing products in cracks, advancing the understanding of self-healing construction biomaterials. [ABSTRACT FROM AUTHOR]

Summary: Ensuring the seamless operation of cloud computing services is paramount for meeting user demands and ensuring business continuity. Fault‐tolerant self‐healing techniques play a crucial role in enhancing the reliability and availability of cloud platforms, minimizing downtime and ensuring uninterrupted service delivery. This article systematically categorizes and analyzes existing research on fault‐tolerant self‐healing techniques published between 2005 and 2024. We provide a comprehensive technical taxonomy organizing self‐healing techniques based on fault tolerance processes, encompassing considerations for both reliability and availability. Additionally, we evaluate applications of proactive self‐healing techniques, highlighting their achievements, and limitations in enhancing service continuity. Strategies to address identified weaknesses are discussed, alongside future research challenges and open issues in the domain of cloud resilience. Through this analysis, the article contributes to understanding self‐healing techniques in cloud computing, offering insights into their effectiveness in ensuring service continuity. The findings aim to guide future research efforts in developing more robust and resilient cloud infrastructures, ultimately enhancing overall service reliability and availability. By emphasizing the importance of fault tolerance and self‐healing techniques, this article lays the foundation for advancing the state‐of‐the‐art in cloud computing. [ABSTRACT FROM AUTHOR]

AbstractThis study comprehensively investigates the literature on using bacteria to confer self-repair abilities on concrete and mortar. Although crack-healing is the main objective, calcite-precipitating bacteria affect concrete’s durability and mechanical properties. This article reviews the research on bacteria-based self-healing concrete and its developments from 1984 to 2023. This systematic review was developed by adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. R studio and Vosviewer were used to perform bibliometric analysis and visualization of the 295 documents by 874 authors affiliated with 97 sources acquired from Scopus (NY). It is vital to emphasise that the document selection was carried out by two impartial reviewers to prevent any bias. In addition to repairing cracks in the material, the data indicate that applying various self-healing bacteria improves concrete’s mechanical and durability properties. A meta-analysis evaluated the summary effect size of the most cited articles. It was concluded with the statistical evidence from the meta-analysis that bacteria incorporated concrete, which shows self-healing efficiency of 5.07 and 7.29 times than that of control concrete. [ABSTRACT FROM AUTHOR]

Hydrogel electrolytes are an integral part of flexible solid-state supercapacitors. To further improve the low ionic conductivity, large interfacial resistance and poor cycling stability for hydrogel electrolytes, the V4C3Tx MXene-enhanced polyvinyl alcohol hydrogel electrolyte was fabricated to enhance its mechanical and electrochemical performance. The high-conductivity V4C3Tx MXene (16,465.3 S m−1) bonding transport network was embedded into the PVA-H2SO4 hydrogel electrolyte (PVA- H2SO4-V4C3Tx MXene). Results indicate that compared to the pure PVA-H2SO4 hydrogel electrolyte (105.3 mS cm−1, 48.4%@2,800 cycles), the optimal PVA-H2SO4-V4C3Tx MXene hydrogel electrolyte demonstrates high ionic conductivity (133.3 mS cm−1) and commendable long-cycle stability for the flexible solid-state supercapacitors (99.4%@5,500 cycles), as well as favorable mechanical flexibility and self-healing capability. Besides, the electrode of the flexible solid-state supercapacitor with the optimal PVA-H2SO4-V4C3Tx MXene hydrogel as the solid-state electrolyte has a capacitance of 370 F g−1 with almost no degradation in capacitance even under bending from 0° to 180°. The corresponding energy density for flexible device is 4.6 Wh kg−1, which is twice for that of PVA-H2SO4 hydrogel as the solid-state electrolyte. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) are prized for their selective dissolution of carbon dioxide (CO2), leading to their widespread use in ionogel membranes for gas separation. Despite their advantages, creating sustainable ionogel membranes with high IL contents poses challenges due to limited mechanical strength, leakage risks, and poor recyclability. Herein, we leverage copolymerized and supramolecularly bound ILs to develop ionogel membranes with high mechanical strength, zero leakage, and excellent self‐healing and recycling capabilities. These membranes exhibit superior ideal selectivity for gas separation compared to other reported ionogel membranes, achieving a CO2/nitrogen selectivity of 61.7 and a CO2/methane selectivity of 24.6, coupled with an acceptable CO2 permeability of 186.4 Barrer. Additionally, these gas separation ionogel membranes can be upcycled into ionic skins for sensing applications, further enhancing their utility. This research outlines a strategic approach to molecularly engineer ionogel membranes, offering a promising pathway for developing sustainable, high‐performance materials for advanced gas separation technologies. [ABSTRACT FROM AUTHOR]

Self‐healing research based on commercial polymeric materials (such as polyurethane) is beneficial to sustainable development by prolonging the life of materials. However, developing polymeric materials that integrate robust mechanical properties with self‐healing ability at ambient temperature remains a formidable challenge. The formation of polymeric materials by physically and chemically dual crosslinking structures is a powerful method to improve mechanical properties. Herein, a series of dual crosslinking self‐healing polyurethane have been designed and successfully synthesized by incorporating 2‐ureido‐4[1H]‐pyrimidinone (UPy) units and triethanolamine (TEOA) into the polymer networks. Relying on the reinforcement of chemical crosslinking which is induced by TEOA, the resulting polyurethane exhibited robust strength of 10.3 MPa and elongation at break of 569.4%, which are quite prominent compared with previous reports. At the same time, the recombination of hydrogen bonds makes the polyurethane with UPy structure achieve rapid self‐healing after 24 h at 40°C and the strength recovered to 4.98 MPa. This work provided a novel way to fabricate sustainable polyurethane with robust mechanical properties. [ABSTRACT FROM AUTHOR]

Limestone calcined clay cement (LC3), enhanced through reactions with volcanic ash and the interaction between limestone and clay, significantly improves the performance of cementitious materials. It has the potential to cut CO2 emissions by up to 30% and energy consumption in cement manufacture by 15% to 20%, providing a promising prospect for the large-scale production of low-carbon cement with a lower environmental effect. To effectively manufacture LC3 concrete, this study utilized limestone (15%), calcined clay (30%), and gypsum (5%) as supplementary cementitious materials (SCMs), replacing 50% of ordinary Portland cement (OPC). However, in regions abundant in sulfate, sulfate attack can cause interior cracking of concrete, reducing the longevity of the building. To address this issue, microcapsules containing microcrystalline wax, ceresine wax, and nano-CaCO3 encapsulated in epoxy resin were prepared and successfully incorporated into LC3 concrete. Sulfate resistance tests were conducted through sulfate dry–wet cycles, comparing samples with and without microcapsules. The findings revealed that the initial mechanical and permeability properties of LC3 concrete did not significantly differ from OPC concrete. LC3 concrete with added microcapsules (SP4) exhibited enhanced resistance to sulfate attack, reducing mass loss and compressive strength degradation. SEM images displayed a mesh-like structure of repair products in SP4. After 14 days of self-repair, SP4 exhibited a 44.2% harmful pore ratio, 98.1% compressive strength retention, 88.7% chloride ion diffusion coefficient retention, 91.12 mV maximum amplitude, and 9.14 mV maximum frequency amplitude. The experimental results indicate that the presence of microcapsules enhances the sulfate attack self-healing performance of LC3 concrete. [ABSTRACT FROM AUTHOR]

Variable stiffness materials have shown considerable application in soft robotics. However, previously reported materials often struggle to reconcile high stiffness, stretchability, toughness, and self‐healing ability, because of the inherently conflicting requisite of these properties in molecular design. Herein, we propose a novel strategy that involves incorporating acid‐base ionic pairs capable of from strong crosslinking sites into a dense and robust hydrogen‐bonding network to construct rigid self‐healing polymers with tunable stiffness and excellent toughness. To demonstrate these distinct features, the polymer was employed to serve as the strain‐regulation layers within a fiber‐reinforced pneumatic actuator (FPA). The exceptional synergy between the configuration versatility of FPA and the dynamic molecular behavior of the supramolecular polymers equips the actuator with simultaneous improvement in motion dexterity, multimodality, loading capacity, robustness, and durability. Additionally, the concept of integrating high dexterity at both macro‐ and micro‐scale is prospective to inspire the design of intelligent yet robust devices across various domains. [ABSTRACT FROM AUTHOR]

Hierarchical design was applied to core-shell B 2 O 3 @SiO 2 microcapsule, followed by fabrication of the SiC–B 2 O 3 @SiO 2 coating by a combination of entrapping and hot dip processes. Among the C/C-SiC-BS2, C/C-SiC-BS4 and C/C-SiC-BS6 samples, the C/C-SiC-BS4 composite exhibits long-term antioxidant capabilities, with only a 2.30 % mass loss as oxidized at 973 K for 1500 h, and 2.35 % at 1073 K for 2600 h. Furthermore, after enduring 150 thermal shocks between 293 K and 1173 K, its mass loss is only 2.07 %. The XRD patterns detected the existence of B 2 O 3 and SiO 2 phases, and the SEM and EDS analysis proved the borosilicate glass, indicating the excellent performances came from the synergistic self-healing effects of the B 2 O 3 , SiO 2 phases, and borosilicate glass. Thus, within the temperature ranges from 873 K to 1273 K, the oxygen penetration shifts from osmotic state to defect diffusion in coating. This research emphasizes the significance of hierarchical designs for core-shell sacrificial phase in silicate coatings, thereby enhancing their long-term applicability. • Hierarchical design was applied to the B 2 O 3 @SiO 2 microcapsule by a simple sol-gel technique. • Core-shell microcapsule successively activated the SiO 2 , B 2 O 3 phases and borosilicate glass in self-healing. • The composite yielded excellent combinations of long-term antioxidant and thermal shock resistances. • This study highlights the hierarchical designs for core-shell sacrificial phase in silicate coatings. [ABSTRACT FROM AUTHOR]

Self-healing composites are smart materials that can self-detect and prevent micro crack propagation and any catastrophic failure in the composite structure. In this study, dicyclopentadiene (DCPD) monomer was encapsulated with urea formaldehyde (UF) by in situ polymerization. These microcapsules were mixed with epoxy, chopped carbon fiber (CF), and multi-walled carbon nanotubes (CNT) to make self-healing composite. Both microcapsules and the composite specimens were extensively tested for their physical, thermal, and mechanical properties. The average diameter and shell thickness of the microcapsules were 268 µm and 805 nm, respectively. DMA analysis suggested that the microcapsules have a glass transition temperature (Tg) of 85°C. FTIR analysis confirmed the presence of CF, multi-walled carbon nanotubes (MWCNT), and other constituents in the composite. The tensile strength of the self-healing composites was tested as per ASTM standards. The incorporation of MWCNT in the composites has significantly improved the tensile strength of the composite without compromising on the self-healing efficiency (90%) compared the unmodified samples (72%). The encouraging results of higher glass transition temperature (85°C) combined with an improved healing efficiency (90%), can be considered as the novelties of this work. As the test results of microcapsules and composite specimens were encouraging, they can find applications in making composite structures for aerospace, windmills, and marine applications. The experimental observations and test results are discussed in detail. [ABSTRACT FROM AUTHOR]

Self-healing, stretchable, and moldable hydrogels have a great potential application in tissue engineering and soft robotics. Despite great success in reported hydrogels, it is still a great challenge to construct the moldable hydrogels with an ultrafast self-healing performance. Herein, the composite hydrogels (PBLH) with ultrafast self-healing, stretchable, and moldable properties were successfully constructed by poly (vinyl alcohol) (PVA), borate (B), ε-poly-l-lysine (EPL), and hyaluronic acid (HA) based on an efficient one-pot method. Fourier transform infrared spectroscopy, X-ray diffraction, and rheological measurements confirmed the formation of a dynamic network among PVA, B, EPL, and HA through the cross-linking of dynamic borate bonds, electrostatic interaction, and hydrogen bonding. Having fabricated the dynamic network structure, the damage gap of the composite hydrogels can heal within 1 min, presenting an excellent self-healing ability. Simultaneously, the composite hydrogels can be molded into various shapes, and the length of the composite hydrogels can be stretched to 15 times their original length. In addition, the composite hydrogels exhibited an excellent antibacterial property against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Our results illustrated that the composite hydrogels not only retain the advantages of traditional hydrogels but also possess ultrafast self-healing, outstanding stretchable and antibacterial properties, presenting a prospective candidate for constructing biomedical materials. [ABSTRACT FROM AUTHOR]

A study combining multiscale numerical simulation and low-velocity impact (LVI) experiments was performed to explore the comprehensive effects on the impact-resistance of EMAA filaments incorporated as thermoplastic healing agents into a plain woven composite. A multiscale micro–meso–macro modeling framework was established, sequentially propagating mechanical performance parameters among micro–meso–macro models. The equivalent mechanical parameters of the carbon fiber bundles were predicted based on the microscopic model. The mesoscopic representative volume element (RVE) model was crafted by extracting the actual architecture of the monolayer EMAA filaments encompassing the plain woven composite. Subsequently, the fiber and matrix of the mesoscopic model were transformed into a monolayer-equivalent cross-panel model containing monolayers aligned at 0° and 90° by local homogenization, which was extended into a macroscopic equivalent model to study the impact-resistance behavior. The predicted force–time curves, energy–time curves, and damage profile align closely with experimental measurements, confirming the reliability of the proposed multiscale modeling approach. The multiscale analysis reveals that the EMAA stitching network can effectively improve the impact-resistance of plain woven composite laminates. Furthermore, there exist positive correlations between EMAA content and both impact-resistance and self-healing efficiency, achieving a self-healing efficiency of up to 98.28%. [ABSTRACT FROM AUTHOR]

In order to prevent structural damage or high repair costs caused by concrete crack propagation, the use of microbial-induced CaCO3 precipitation to repair concrete cracks has been a hot topic in recent years. However, due to environmental constraints such as oxygen concentration, the width and depth of repaired cracks are seriously insufficient, which affects the further development of microbial self-healing agents. In this paper, a ternary microbial self-healing agent composed of different proportions of Bacillus pasteurii, Saccharomyces cerevisiae, and Bacillus mucilaginosus was designed, and its crack repair ability was evaluated. When the mixing ratio was 7:1:2, the cell concentration was the highest, the precipitation amount of CaCO3 was the highest, and the crystallinity of calcite crystal was the highest. Compared to the single microorganism, the mortar specimens with ternary microorganisms had the largest repair area (up to 100%) and the deepest repair depth (CaCO3 presents at 9–12 mm from the crack surface). This is because when the concrete breaks, all three microorganisms are activated by water, O2, and CO2. Saccharomyces cerevisiae and Bacillus mucilaginosus accelerated the growth of Bacillus pasteurii and more mineralized products; CaCO3 was rapidly formed and quickly filled on the crack surface. When CaCO3 seals the surface of the crack, the internal Saccharomyces cerevisiae and Bacillus mucilaginosus continue to play a role. Bacillus mucilaginosus can accelerate the dissolution of CO2 produced by the anaerobic fermentation of Saccharomyces cerevisiae and the hydrolysis of CO32−, thereby improving the repair of the crack depth direction. [ABSTRACT FROM AUTHOR]

Polymeric composites are prone to undergoing damage, such as microcracks, during their operation, which can ultimately lead to catastrophic failure. To contradict such a problem, efforts have been carried out, by the scientific community, towards developing self-healing composites that, by mimicking biological systems, can autonomously and prematurely repair flaws, extending the durability and improving the security of materials. The present review explores the progress made in this area, focusing on extrinsic self-healing methods, as these can be employed to a variety of materials. Reservoir-based techniques, which resort to capsules, hollow fibers or microvascular networks, and thermoplastic-based ones are overviewed, prioritizing innovative approaches made in recent years. At last, promising practical applications for self-healing composites are highlighted and future challenges and opportunities are pointed out. [ABSTRACT FROM AUTHOR]

Poly(thiourethane)‐based covalent adaptable networks are synthesized by reacting a trimer of hexamethylene diisocyanate (Desmodur N3300) containing isocyanurate groups in its structure with 1,6‐hexanedithiol. The catalysts evaluated for this process include dibutyltin dilaurate (DBTDL), lanthanum triflate (La(OTf)3), and a thermal precursor of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (BGDBU). The use of DBTDL results in the initiation of curing upon mixing, while the other two catalysts exhibit a latency period in the reactive mixture, with curing starting at about 90 °C. Notably, the use of the lanthanum salt produces an additional minor exothermic reaction at 80 °C. This phenomenon corresponds to the trimerization of isocyanates rending isocyanurates, leaving a portion of unreacted thiols. Materials prepared with BGDBU or La(OTf)3 present shorter relaxation times than those prepared with DBTDL. Nevertheless, the materials containing the lanthanum salt do not reach complete relaxation, likely due to the reinforcement of the permanent network through increased isocyanurate content. The formation of isocyanurates produces a stoichiometric imbalance, leaving unreacted thiols. This transforms the exchange process into a dual mechanism involving a dissociative process of thiourethanes to isocyanate and thiol, along with an interchange through thiol attacking the thiourethane group. The materials exhibit good recyclability and self‐healing characteristics. [ABSTRACT FROM AUTHOR]

Flexible membrane with good anti‐wettability under giant deformation and fast healing will largely extend its adaptability and life span in anti‐/deicing application. A flexible membrane with significant dynamic water repellency and photo‐/electro‐responsive healing capability is reported, fabricated by combining the covalent grafting of fluorosilane to carbon black (F‐CB) with the optimized ablation difference between thermoplastic polyurethane (TPU) matrix and F‐CB. A rolling angle of below 5° is remained after either being stretching to 1000% strain or 2000 cycles of tensile tests at 400% strain. More importantly, multi‐scale cracks on the membrane can be diagnosed and repaired in real‐time; the healing efficiency reaches above 99% within 90 s even if completely fractured under the effect of both solar irradiation of 0.1 W cm−2 and applied voltage of 20 V; and all‐weather anti‐/deicing has the performance of an icing delay time of 323 s and an ice adhesion strength of <40 kPa, a sharp contrast to the 18 s and 1090 kPa, respectively, for bare metal surface. This work endows anti‐icing membrane with the ability of damage detection and cyclic healing, highly demanded in outdoor anti‐/deicing application that involve inevitable mechanical damages. [ABSTRACT FROM AUTHOR]

Fiber‐based multimodal sensors with electrical/optical signals are highly desired for next‐generation wearable electronics. Despite the remarkable progress in this area, achieving large‐scale knittable, washable, and self‐healing performance in fiber‐based multimodal sensors simultaneously remains a great challenge. Here, a smart fiber capable of exhibiting piezoresistive/luminescent properties based on an H‐bonding connected multilayered core–shell nanostructure is developed. The core principle of this design involves constructing strong interfacial interactions between the fiber layers, which results in a sensor with high sensitivity (gauge factor = 12383500), exceptional water resistance, and robust self‐healing properties (tensile strength 30.9 MPa, healing efficiency 72.9%). Unlike traditional fiber‐based sensors where elaborate nanostructures are prone to shedding during knitting, this strategy enables the fiber sensors with excellent knittability to be patterned in the fabric, improving both optical and electrical sensitivities. This work is anticipated to make a significant contribution to the further development of wearable electronic products and visual human–computer interaction electronic devices. [ABSTRACT FROM AUTHOR]

This study investigates a neoteric approach in manufacturing lunar regolith-filled shape memory vitrimer (SMV) composites for extraterrestrial applications. A SMV with robust mechanical properties was combined with locally available lunar regolith to form a composite material. Fourier Transfer Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), Thermogravimetric Analysis (TGA), and X-ray fluorescence (XRF) were used to characterize the resin, the regolith simulant, and the prepared SMV-regolith composites. We explored conventional synthesis as well as 3D printing methods for manufacturing the composite. Glass fabric-reinforced laminated composites were also prepared to evaluate the impact tolerance and damage healing efficiency. Compressive strength, flexural strength, and impact resistance of the composite were tested at both room and elevated temperatures. A compressive strength of 96.0 MPa and 5.4 MPa were recorded for composite with 40 wt% regolith ratio at room and elevated temperatures, respectively. The glass fabric reinforced SMV-regolith laminate exhibited a bending strength of 232.7 MPa, good impact tolerance under low-velocity impact test, and good healing efficiency up to two damage healing cycles. The 3D printed SMV-regolith composite using a liquid crystal display (LCD)-based printer exhibited a good thermomechanical property with a compressive and tensile strength of 139.16 MPa and 13.99 MPa, respectively, and a good shape memory effect. However, the LCD-based printing using vat-photopolymerization limits the size of the printed samples. Nonetheless, this study shows that utilization of regolith to form advanced composite is possible. SMV regolith composite is a promising material for lunar base applications due to its simple manufacturing process, excellent mechanical properties, and low energy consumption. [ABSTRACT FROM AUTHOR]

Elastomers with high mechanical toughness can guarantee their durability during service life. Self-healing ability, as well as recyclability, can also extend the life of materials and save the consuming cost of the materials. Many efforts have been dedicated to promoting the mechanical toughness as well as the self-healing capability of elastomers at the same time, while it remains a challenge to balance the trade-off between the above properties in one system. Herein we proposed a molecular design driven by dual interactions of acylsemicarbazide hydrogen bonding and Cu2+-neocuproine coordination simultaneously. By introducing the reversible multiple hydrogen bonds and strong coordination bonds, we successfully fabricated an extremely tough and self-healing elastomer. The elastomer can achieve an impressive top-notch toughness of 491 MJ/m3. Furthermore, it boasted rapid elastic restorability within 10 min and outstanding crack tolerance with high fracture energy (152.6 kJ/m2). Benefiting from the combination of dynamic interactions, the material was able to self-repair under 80 °C conveniently and could be reprocessed to restore the exceptional mechanical properties. [ABSTRACT FROM AUTHOR]

Conventional epoxy anhydride curing systems typically require large amounts of catalyst to ensure a high ester exchange rate, and the resulting cured epoxy vitrimer has renewable and self-repairing properties, but is limited by the amount of catalyst loading. In this study, a diol (VT) containing imine bonds was synthesized from vanillin (VAN) and tyramine (TA) to catalyze the epoxy-anhydride curing process, and glycerol triglycidyl ether (GTE) was co-cured with VT and methylhexahydrophthalic anhydride (MHHPA), which constructed a bio-based regenerative and repairable epoxy vitrimer with dual dynamic covalent bonds (GMV), the free hydroxyl groups in the crosslinked network could rapidly promote the ester exchange rate. The thermal, mechanical, solvent resistance, self-repairing, renewable and shape memory properties of GMV were systematically investigated by adjusting the ratio of anhydride and hydroxyl groups. It exhibits a better thermal stability property Td5% (281.27℃) and a shorter relaxation time τ (12.15 s) at 140 °C. In addition, the scratches of GMV could be almost completely healed at 120 °C for 60 min, and this test demonstrated that GMV has better self-healing and renewable tests. The present work promotes the epoxy vitrimer species and expands the esterification scheme performed without catalyst. [ABSTRACT FROM AUTHOR]

Copyright of Paint & Coatings Industry (0253-4312) is the property of Paint & Coatings Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Paint & Coatings Industry (0253-4312) is the property of Paint & Coatings Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Paint & Coatings Industry (0253-4312) is the property of Paint & Coatings Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The increased demand for high energy‐density batteries led to using lithium metal (Li) anode. However, safety issues associated with Li anode encouraged the researchers to use less reactive and safer electrolytes with higher electrochemical stability. High ionic conductivity (σ), wider electrochemical stability window, and higher mechanical strength alongside the ability to self‐heal possible structural damages were at the center of focus for developing efficient solid electrolytes. In this regard, we developed a group of solid polymer electrolytes (SPEs) with high σ and electrochemical stability. In this regard, bottle brush polyethylene glycol (bbPEG) was synthesized using a chain transfer reaction. Polynipaam (PNIPAAM) blocks were also incorporated into the structure to prepare a block copolymer based on PNIPAM‐bbPEG‐PNIMAM represented by the ABA structure. The block copolymer was then blended with polyvinylidene fluoride (PVDF) with the block copolymer to PVDF weight ratio of 7:2% and 25% bis(trifluoromethane) sulfonamide (TFSI) salt was added and the final mixture was UV‐cured. The results indicated that the final SPE possessed high ionic conductivity with a relatively high lithium‐ion transference number (tLi+$$ {t}_{Li+} $$) of 0.416 and the σ of 1.265 × 10−5 S/cm at 25°C. [ABSTRACT FROM AUTHOR]

The serious environmental threat caused by petroleum-based plastics has spurred more researches in developing substitutes from renewable sources. Starch is desirable for fabricating bioplastic due to its abundance and renewable nature. However, limitations such as brittleness, hydrophilicity, and thermal properties restrict its widespread application. To overcome these issues, covalent adaptable network was constructed to fabricate a fully bio-based starch plastic with multiple advantages via Schiff base reactions. This strategy endowed starch plastic with excellent thermal processability, as evidenced by a low glass transition temperature (Tg = 20.15 °C). Through introducing Priamine with long carbon chains, the starch plastic demonstrated superior flexibility (elongation at break = 45.2%) and waterproof capability (water contact angle = 109.2°). Besides, it possessed a good thermal stability and self-adaptability, as well as solvent resistance and chemical degradability. This work provides a promising method to fabricate fully bio-based plastics as alternative to petroleum-based plastics. [ABSTRACT FROM AUTHOR]

Material extrusion‐based additive manufacturing (AM) process builds the objects/structures through a precise feedstock deposition in a layer‐by‐layer manner. Polylactic acid (PLA) is a popular biodegradable feedstock in AM, while octyl methoxycinnamate (OMC) is known for its eco‐friendliness and ultraviolet (UV) protection properties. The present study focuses on the novel infusion methodology of OMC‐based microcapsules into PLA to develop self‐healing composite filaments. Post‐composition iterations, the optimum compositions for the filler and plasticizer were determined, and the filaments were extruded. Microcapsule‐infused PLA and the neat PLA samples were printed as per the American Society for Testing and Materials (ASTM) standard. The uniaxial tensile test results showed that the failure strain endured by the microcapsule‐infused samples was about 10 times more than the neat PLA counterparts. It is attributed to the effective load distribution and the complex polymerization reaction (due to the interaction of OMC with the matrix). Fracture surface morphology of the samples via optical microscopy (OM) and field emission scanning electron microscope (FESEM) affirmed the strong PLA‐OMC interface. A depreciation in the Brinell Hardness for the microcapsule‐based samples was due to the localized indenter force, causing greater damage in a narrow area than microcapsule ruptures' healing ability. Highlights: The optimized composition of PLA: plasticizer:microcapsule is 1:0.04:0.05.Microcapsule‐infused PLA has improved Young's modulus and failure strain.Interaction with microcapsules improves elastic behavior and self‐healing.FESEM reveals close bonding of microcapsule with the PLA matrix. [ABSTRACT FROM AUTHOR]

Polymeric materials have penetrated all aspects of society and play an irreplaceable role. However, there is an inherent contradiction between their mechanical properties and processing behavior. Here, inspired by cement, a crucial construction material renowned for its excellent fabricating behavior and self-strengthening properties, we have developed dynamic cross-linked poly(oxime-urethane) (CPOU). The synthesized CPOU showed good self-healing ability and 3D printability owing to the dynamic dissociation and re-association of oxime-carbamate bonds. Simple objects printed through the fused deposition modeling technique were able to be readily assembled into complex architectures through intrinsic self-healing. Furthermore, the self-strengthening of CPOU was successfully realized through multiple-step tandem reactions. The dissociation of dynamic oxime-carbamate bonds produced–NCO groups, which reacted with the surrounding water to form polar urea bonds in the polymer network, leading to an increase in the tensile strength of CPOU from 11.95 to 19.37 MPa. This work not only develops the polymers with combined self-healing, facile fabricating, and self-strengthening properties but also provides a new molecular strategy to modulate the properties of polymers, which could be potentially applied in diverse areas. [ABSTRACT FROM AUTHOR]

The mechanical properties of concrete structures change under repeated sulfate salt erosion, a transformation observable through the evolving energy characteristics during compression. This study conducts uniaxial compression tests on ordinary concrete under repeated sulfate solution and pure water erosion, referencing uniaxial compression tests on concrete with admixtures under sulfate solution erosion, comparing and analyzing their mechanical properties and energy conversion characteristics. Findings indicate: (1) Repeated sulfate erosion increases the nonlinearity of the concrete’s stress-strain curve, especially during the initial compaction phase. Regardless of peak strength, both the energy dissipation curve and damage variables defined by dissipated energy show consistent trends. This suggests that sulfate salts react within the concrete, generating new substances that fill pores, temporarily increasing the elastic modulus while degrading the original structure, ultimately leading to brittle failure. (2) Considering repair effectiveness, protection of repair products, and the evolution of dissipated energy, peak strength variations, and SEM images of internal microcracks, the optimal timing for self-healing in ordinary concrete is suggested to be after 14 wet-dry cycles. (3) Under repeated sulfate salt erosion, the stress-strain relationship of ordinary concrete significantly deviates from traditional damage constitutive models, especially during initial compaction phase. Constitutive models based on damage variable evolution and dissipated energy show better agreement with experimental results in this phase.

Abstract Dental restorative resin composites are widely used to repair tooth decay owing to attractive esthetics, adequate mechanical properties and minimally invasive tooth structure preparations. Nevertheless, dental restorative resin composites still face challenges because of their relatively high failure rate and short lifespan caused by secondary caries and bulk fracture. Thus, attempts have been carried out to explore a new generation of dental restorative resin composites with antibacterial, remineralizing, and self-healing capabilities to inhibit bacteria and lengthen the lifetime of the restorations. Such novel restorative composites can inhibit bacterial activity, reduce acid production, promote mineral regeneration and present a renewable advantage to achieve a higher performance, which are inspiring and provide support for further basic and clinical research. In this review, antibacterial dental restorative resin composites are first introduced, followed by remineralizing, self-healing, and multifunctional dental resin composites with two or more of the functions mentioned above. Meanwhile, we explain the mechanism of the corresponding dental restorative resin composites and describe their characteristics. Finally, we conclude and put forward prospects. This review will attract both researchers and clinicians in this field and help to provide innovative ideas to design new restorative resin composites for biomedical applications. Graphical abstract

This study introduces a pioneering design concept termed the “dual-feedback healing mechanism”, which investigates the relationship between oxidation products and protective coatings. Specifically, it focuses on channeling oxidation products generated at exposed cracks in the substrate to interact with the antioxidant coatings, enabling a self-repair mechanism for cracks. BNf/SiBN was chosen as the ceramic matrix, while the Si‒O‒Al system served as the antioxidant coating. The dynamic process of obtaining Si–O–Al (SOAC) coating involving the pyrolysis of organic precursors and the dual-feedback healing mechanism were systematically investigated. These findings indicate that when the temperature surpasses 1150 °C, the exposed BN fibers at the cracks are oxidized, transforming into B2O3(g). Subsequently, B2O3(g) reacts with SiO2, forming a SiBO mixture. The mixture effectively diminishes the viscosity of the coating, enabling it to flow and form a fresh protective layer that effectively blocks O2 infiltration. Consequently, after oxidation at 1500 °C, the coated samples experience a mere 3% weight loss. This technology emphasizes the interconnectivity during material transformation, utilizing matrix oxidation products as a driving force for self-healing of the coating. This approach achieves intelligent-like, targeted closure of oxygen pathways, thereby pioneering a novel concept and direction for the advancement of antioxidant coatings. Consequently, this approach not only enhances our understanding of the fundamental nature of “self-healing” but also holds significant potential in the development of reparable antioxidant coatings.

Abstract Earthquakes present formidable challenges to structural stability, driving the need for ongoing advancements in construction methodologies. This review highlights the crucial role of Geopolymer Concrete (GPC) in enhancing earthquake resistance and addresses the need for innovative solutions. The review begins with an overview of the importance of earthquake-resistant construction practices, emphasizing that the next generation of GPC can increase flexural strength by up to 30% compared to conventional GPC concrete when incorporating nanomaterials such as nano-Al2O3, nano clays, and nano-SiO2. A detailed survey of current earthquake-resistant strategies reveals that while traditional concrete is susceptible to chloride attacks, GPC demonstrates a 37% lower vulnerability and significantly improved durability under harsh environmental conditions. The paper presents real-world case studies where GPC has been successfully implemented in seismic applications, illustrating effective enhancements in structural resilience metrics. The review then explores various emerging strategies for earthquake-resistant GPC, elucidating their unique features and advantages for seismic applications. Real-world case studies and examples illustrate the practical success and effectiveness of these next-generation strategies in improving structural resilience. The paper also outlines performance evaluation criteria for seismic structures, showing how these new approaches offer notable improvements over traditional methods. Challenges associated with implementing these advanced strategies are discussed, along with innovative solutions and recent advancements in the field. A comparative analysis of traditional and next-generation approaches highlights their respective benefits and potential drawbacks. The review concludes with an outline of future research directions and prospects for further enhancing GPC structures against seismic forces. This review consolidates key findings and underscores the transformative potential of next-generation strategies in earthquake-resistant construction.

Microwave absorption (MA) materials are essential for protecting against harmful electromagnetic radiation. In this study, highly efficient and ultrawide-band microwave-absorbing fabrics with superhydrophobic surface features were developed using a facile dip-coating method involving in situ graphene oxide (GO) reduction, deposition of TiO2 nanoparticles, and subsequent coating of a mixture of polydimethylsiloxane (PDMS) and octadecylamine (ODA) on polyester fabrics. Owing to the presence of hierarchically structured surfaces and low-surface-energy materials, the resultant reduced GO (rGO)/TiO2-ODA/PDMS-coated fabrics demonstrate superhydrophobicity with a water contact angle of 159° and sliding angle of 5°. Under the synergistic effects of conduction loss, interface polarization loss, and surface roughness topography, the optimized fabrics show excellent microwave absorbing performances with a minimum reflection loss (RLmin) of −47.4 dB and a maximum effective absorption bandwidth (EABmax) of 7.7 GHz at a small rGO loading of 6.9 wt%. In addition, the rGO/TiO2-ODA/PDMS coating was robust, and the coated fabrics could withstand repeated washing, soiling, long-term ultraviolet irradiation, and chemical attacks without losing their superhydrophobicity and MA properties. Moreover, the coating imparts self-healing properties to the fabrics. This study provides a promising and effective route for the development of robust and flexible materials with microwave-absorbing properties.

Dynamic cross-linked networks (DCNs) endow thermoset rubber with self-healability and recyclability to extend its lifetime and alleviate environmental pollution. However, the contradiction between high self-healing and mechanical properties in DCNs rubber is always difficult to be resolved. Herein, we used boronic ester (BO) and Diels-Alder dynamic covalent bonds (DA) to synthesize polybutadiene-based dual networks rubber (PB-BO-DA) via thiol-ene reaction. This approach achieved a tensile strength of 16.46 MPa and 99% self-healing efficiency, facilitated by extensive intermolecular interactions (π-π packing and N-B coordination) and fully dynamic cross-linking. In addition, multiple dynamic cross-linked networks (MDCNs) polybutadiene-based rubber also show excellent shape memory ability and recyclability. This strategy might open a helpful pathway to fabricate intelligent multifunctional polymers with high strength and high self-healing efficiency.

[Display omitted] Traditional kinesiology tape (KT) is an elastic fabric tape that clinicians and sports trainers widely use for managing ankle sprains. However, inadequate mechanical properties, adhesive strength, water resistance, and micro-damage generation could affect the longevity of the tape on the skin during physical activity and sweating. Therefore, autonomous room-temperature self-healing elastomers with robust mechanical properties and adequate adhesion to the skin are highly desirable to replace traditional KT. Ionic aggregates were introduced into the polymer matrix via electrostatic attraction between polymer colloid and polyelectrolyte to achieve such elastic tape. These ionic aggregates act as physical crosslink points to enhance mechanical properties and dissociate at room temperature to provide self-healing functions. The obtained elastic tape possesses a tensile strength of 3.7 MPa, elongation of 940 %, toughness of 16.6 MJ∙m−3, and self-healing efficiency of 90 % for 2 h at room temperature. It also exhibits adequate reversible adhesion on the skin via van der Waals force and electrostatic interaction in both dry and wet conditions. The new elastic tapes have great potential in biomedical engineering for preventing and rehabilitating ankle sprain. [ABSTRACT FROM AUTHOR]

A new silane coupling agent is designed to fabricate a self-healing composite electrolyte with dynamic disulfide bonds and hydrogen bonds, which exhibits superior Li compatibility, excellent electrochemical performance in full cells, and great application potential in flexible all-solid-state Li metal batteries. [Display omitted] Composite solid electrolytes (CSEs), which combine the advantages of solid polymer electrolytes and inorganic solid electrolytes, are considered to be promising electrolytes for all-solid-state lithium metal batteries. However, the current CSEs suffer from defects such as poor inorganic/organic interface compatibility, lithium dendrite growth, and easy damage of electrolyte membrane, which hinder the practical application of CSEs. Herein, a CSE (PBHL@LLZTO@DDB) with polyurethane (PBHL) as the polymer matrix and Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO) modified by silane coupling agent (DDB) as inorganic fillers (LLZTO@DDB) has been prepared. Disulfide bond exchange reactions between PBHL and LLZTO@DDB enable PBHL@LLZTO@DDB to form a dynamic three-dimensional (3D) inorganic/organic hybrid network, which promotes the uniform dispersion of LLZTO in PBHL@LLZTO@DDB, improves the Li+ conductivity (1.24 ± 0.08 × 10−4 S cm−1 at 30 ℃), and broadens the electrochemical stability window (5.16 V vs. Li+/Li). Moreover, a combination of hydrogen bonds and disulfide bonds endows PBHL@LLZTO@DDB with excellent self-healing properties. As such, both all-solid-state symmetric and full cells exhibit excellent cycle performance at ambient temperature. More importantly, the healed PBHL@LLZTO@DDB can almost completely restore its original electrochemical properties, indicating its application potential in flexible electronic products. [ABSTRACT FROM AUTHOR]

[Display omitted] Flexible electronics have introduced new challenges for efficient human–machine interactions. Hydrogels have emerged as prominent materials for electronic wearable applications due to their exceptional mechanical deformability and lightweight characteristics combined in some cases with conductive properties, and softness. Additionally, bio-interphases require multisensory response to stress, strain, temperature, and self-healing capacity. To mimic these properties, this work developed interpenetrated hydrogel networks composed of chitosan (CHI) and polyacrylic acid (PAA), combined with Fe (III) ions and varying amounts of NMBA (0–0.25 %), to achieve tailored conductivity (0.8–2.5 mS/cm), self-healing, self-standing and mechanical properties (E = 11.7–110 Pa and fracture strain = 64.9–1923 %) suitable for strain sensor applications. The results revealed a significant influence of the restrictive effect on the mobility of uncrosslinked chain segments, caused by Fe ions and NMBA, on the piezoresistance (GF 2.1–1.3) and self-healing capability of the gels. Interestingly, a transparent/turbid transition, driven by microphase separation that is characteristic of systems with high dynamic interactions, was encountered for the first time in these hydrogels. This transition was analyzed in relation to external temperature, water content, pH, and the influence of Fe ions and NMBA. The simultaneous sensitivity of these materials to temperature and pH, along with their piezoresistive and self-healing behaviour, can be highly valuable for multifunctional sensors in a wide range of applications. [ABSTRACT FROM AUTHOR]

[Display omitted] 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. [ABSTRACT FROM AUTHOR]

Microcapsule technology is a promising approach for enhancing the self-healing ability of asphalt pavements. In this study, the self-healing behavior of melamine-urea-formaldehyde (MUF) microcapsules was investigated. The microcapsules were synthesized using an in situ polymerization method. The proposed healing indicators, combined with fluorescence tracing technology, were used to evaluate the release behavior and sustained repair effect of the microcapsules at different damage levels, healing intervals, aging degrees, and healing temperatures. The results showed that most microcapsules survived at low damage levels, whereas larger microcapsules were more likely to rupture and release the rejuvenators. The sustained self-healing effect of the microcapsules could effectively repair internal damage within the asphalt pavement over an extended service life. Aged asphalt was particularly susceptible to the activation of microcapsules, leading to increased self-healing and the provision of additional rejuvenators for damaged asphalt mastic. Additionally, the self-healing of asphalt mastic with microcapsules had a critical temperature threshold. Microcapsules could enhance the fatigue and self-healing performance of asphalt mastic only when the healing temperature was below a certain value; otherwise, they may lead to adverse effects. The critical healing temperature threshold for thin-film oven testing (TFOT)-aged asphalt increased from approximately 30°C to about 45°C after PAV aging. This study provides a better understanding of the self-healing behavior of microcapsule asphalt, as well as the factors affecting the release behavior and sustained repair effects of the microcapsules. These results can be used to optimize the design and implementation of microcapsule technology to enhance the durability and sustainability of asphalt pavements. [ABSTRACT FROM AUTHOR]

Pavement researchers have sought to develop more environmentally friendly asphalt that effectively mitigates the consumption of natural resources and maintenance costs. They have noted that using durable asphalt with improved self-healing can achieve these goals. Technologies like warm-mix asphalt or calcium capsules can help the economy and substantially reduce environmental impact. These aims can be attained with technologies such as warm-mix asphalt (WMA) and calcium alginate capsules. This study evaluates the effect of Sasobit, which is utilized as a typical modifier for WMA, long-term aging (LTA) and calcium alginate capsules on the self-healing performance and mechanical properties of asphalt mixture by using different tests such as resilient modulus, indirect tensile strength (ITS), fracture test on semicircular bending (SCB) specimens and edge notched disk bend (ENDB) specimens. According to Findings, long–term aging and Sasobit negatively affect the self-healing performance of mixtures, although capsules improve it. Also, ENDB specimens have lower healing values than SCB specimens; however, due to longer crack length, ENDB specimens have more capsules incorporated in healing performance compared to SCB specimens. As a result, this paper notes that the properties of asphalt binder not only have a great effect on the self-healing performance of the mix but also have a significant impact on the action of capsules on healing cracks. [ABSTRACT FROM AUTHOR]

Itaconic acid-based epoxy vitrimers with dual-dynamic covalent bonds （boronic ester bond and ester bond） were fabricated by epoxy-carboxylic acid reaction， itaconic acid derivative as an epoxy monomer， synthesized tricarboxylic acid compound as crosslinker. The structures of the itaconic acid-based epoxy vitrimer and tricarboxylic acid compound were characterized by fourier transform infrared （FT-IR） spectra and proton nuclear magnetic resonance （1H NMR） spectroscopy， and the results show that all of them are successfully prepared. Meanwhile， the mechanical properties， thermal stability， thermo-mechanical properties and stress relaxation testing of the EIA-HBN were examined by tensile testing， thermogravimetric analysis （TG）， and dynamic mechanical analysis （DMA）， and the effects of HBN content on the network properties were studied. Furthermore， the effects of HBN content on self-healing and chemical recycling performances of all the itaconic acid-based epoxy vitrimer networks were researched； the results displayed that the EIA-HBN-6 network possess the excellent self-healing and chemical recycling capabilities.