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Dehydration has been a key limiting factor for the operation of conductive hydrogels in practical application. Here, we report self-healable ionic skins that can self-regulate their internal moisture level by capturing extenral moistures via hygroscopic ion-coordinated polymer backbones through antipolyelectrolyte effect. Results show the ionic skin can maintain its mechanical and electrical functions over 16 months in the ambient environment with high stretchability (fracture stretch ∼2216 %) and conductivity (23.5 mS/cm). The moisture self-regulating capability is further demonstrated by repeated exposures to harsh environments such as 200°C heating, freezing, and vacuum drying with recovered conductivity and stretchability. Their reversible ionic and hydrogen bonds also enable self-healing feature as a sample with the fully cut-through damage can restore its conductivity after 24 h at 40 % relative humidity. Utilizing the ionic skin as a building block, self-healing flexible piezoelecret sensors have been constructed to monitor physiological signals. Together with a facile transfer-printing process, a self-powered sensing system with a self-healable supercapacitor and humidity sensor has been successfully demonstrated. These results illustrate broad-ranging possibilities for the ionic skins in applications such as energy storage, wearable sensors, and human-machine interfaces.

Highlights This research aims to investigate the low‐velocity impact (LVI) response and self‐healing performance of carbon fiber composite laminates (NL) containing staggered hybrid polyamide nanofiber veils. Carbon fiber‐reinforced polymer (CFRP) composites are widely used in many industries, but they are sensitive to LVI damage and there is a lack of research on repair, which restricts their development. In the research, NL samples were prepared, and four impact energies of 6.6, 9.4, 12.2, and 15.0 joules were selected. Ultrasonic C‐scan detection, microscopic observation and mechanical property tests were carried out. The results show that the NL samples have smaller damage areas and degrees, indicating that the veils enhance the impact resistance; the damage repair efficiencies of the NL samples at different energies are 48.3%, 36.2%, 29.7% and 16.8% respectively; when the impact energy is lower than 13.9 J, the flexural strength of the repaired NL samples can be restored to more than 80% of the original strength. These results are of great significance. The improvement of the impact resistance of composites by hybrid polyamide nanofibers can solve the problem of CFRP's sensitivity to LVI damage, and the self‐healing ability provides a new approach to damage treatment, having broad application prospects in aerospace, shipbuilding and other industries. Hybrid veils enhance impact toughness, reducing damage area and severity. Veils enable self‐healing, repair impact damage, and enhance reusability. Repair efficiency is higher at lower impact energy levels. [ABSTRACT FROM AUTHOR]

Flexible luminescent materials are usually in the form of gels and films. Solid‐state films have advantages in practical applications due to their long‐term stability. However, the fabrication process by conventional methods remains laborious and unsustainable. Here, a facile and green route is reported for fabricating flexible luminescent films via an elegant solid‐phase molecular self‐assembly design. First, Eu3+/Tb3+‐based metallosupramolecular coordination polyelectrolytes (MEPEs) and tetraphenylethylene (TPE)‐based MEPEs are designed with an antenna bis‐ligands to get individual R, G, and B emission. Then, by repeatedly pressing the MEPEs‐cetyltrimethylammonium bromide (CTAB) precipitates, obtained from their mixing aqueous solutions, R, G, and B emission films are obtained at room temperature, respectively. The emission color can be simply tuned by adjusting molar ratio of Eu3+: Tb3+: TPE. Notably, humidity‐responsive white emission film is obtained when Eu3+: Tb3+: TPE = 3:1:2.5. Owing to the dynamic coordination and electrostatic interaction, which can be activated by hydrating water, these films can be facilely reprocessed and self‐healed with the aid of water at room temperature. It is hoped that this approach to fabricate flexible supramolecular luminescent films can be applied to design various advanced functional soft materials. [ABSTRACT FROM AUTHOR]

Highlights Ice accretion is a huge concern for many wind blades installed in colder regions. The approach of active de‐icing systems based on coatings has been recently quite explored. Nevertheless, the concern about an external electrically conductive layer leads to the need to develop multilayer insulating/conductive coatings. For this purpose, a novel multilayer coating consisting of a 3D printed carbon nanotube (CNT) and graphene nanoplatelet (GNP) reinforced nanocomposite is proposed, covered by a top coating consisting of a PCL‐based epoxy blend. Here, the CNT/GNP layer presents outstanding Joule heating capabilities due to the enhanced electrical conductivity, which increases significantly when increasing the filler content without drastically affecting the quality of the printed ribbons. More specifically, the temperature reached was about 140°C when applying 30 V for the 4 wt.%CNT and 6 wt.%GNP reinforced specimens. In this regard, this resistive heating can promote the thermal stimulus needed to activate de‐icing and self‐healing mechanisms on the epoxy/PCL top layer. Healing efficiencies obtained by the Joule effect reached up to 90% efficiency in comparison to convective heating, which showed a 68%, explained by the improved heating transfer from the CNT/GNP layer when applying the resistive heating. Finally, a proof‐of‐concept test as a de‐icing system showed a complete ice removal within 2.9 min when applying the resistive heating in the intermediate CNT/GNP layer, proving the multifunctionality of the proposed multilayer coating for self‐heating and self‐healing applications. A multilayer coating with self‐healing and de‐icing capabilities was successfully developed. Great combination of 3 min de‐icing time and 90% self‐healing efficiency. Novel inner 3D printed layer allows higher CNT/GNP contents than traditional ones. A multilayer approach with optimized nanoreinforced area required. [ABSTRACT FROM AUTHOR]

[Display omitted] Stone-built cultural heritage faces threats from natural forces and anthropogenic pollutants, including local climate, acid rain, and outdoor conditions like temperature fluctuations and wind exposure, all of which impact their structural integrity and lead to their degradation. The development of a water-based, environmentally-friendly protective coatings that meet a combination of requirements posed by the diversity of the substrates, different environmental conditions, and structures with complex geometries remains a formidable challenge, given the numerous obstacles faced by current conservation strategies. Here we report the structural, electrical, and mechanical characterization, along with performance testing, of a nanostructured hydrophilic and self-healing hybrid coating based on hydroxyapatite (HAp) nanocrystals and polyelectrolyte multilayers (PEM), formed in-situ on Greek marble through a simple spray layer-by-layer surface functionalization technique. The polyelectrolyte-hydroxyapatite multilayer (PHM) structure resembled the design of naturally forming trabecular bone, attained at a short procedural time. It exhibited chemical affinity, aesthetical compatibility and resistance to weathering while offering reversibility. The proposed method is able to generate micron-sized coatings with controlled properties, such as adhesion and self-healing, leading to less weathered surfaces. Our results show that the PHM is a highly effective protective material that can be applied for stone protection and other similar applications. [ABSTRACT FROM AUTHOR]

The rapid advancement in attractive platforms such as biomedicine and human‐machine interaction has generated urgent demands for intelligent materials with high strength, flexibility, and self‐healing capabilities. However, existing self‐healing ability materials are challenged by a trade‐off between high strength, low elastic modulus, and healing ability due to the inherent low strength of noncovalent bonding. Here, drawing inspiration from human fibroblasts, a monomer trapping synthesis strategy is presented based on the dissociation and reconfiguration in amphiphilic ionic restrictors (7000‐times volume monomer trapping) to develop a eutectogel. Benefiting from the nanoconfinement and dynamic interfacial interactions, the molecular chain backbone of the formed confined domains is mechanically reinforced while preserving soft movement capabilities. The resulting eutectogels demonstrate superior mechanical properties (1799% and 2753% higher tensile strength and toughness than pure polymerized deep eutectic solvent), excellent self‐healing efficiency (>90%), low tangential modulus (0.367 MPa during the working stage), and the ability to sensitively monitor human activities. This strategy is poised to offer a new perspective for developing high strength, low modulus, and self‐healing wearable electronics tailored to human body motion. [ABSTRACT FROM AUTHOR]

Highlights Wind turbines are subjected to extreme weather and load conditions; hence, high strength and impact resistance are required. Furthermore, wind turbine blades can be subjected to impact loads such as bird strikes, resulting in the formation of microcracks. Self‐healing capsules can be used to mend turbine blades for microscale damage. The incorporation of self‐healing capsules may cause a decrease in the mechanical characteristics of the composites prior to impact resistance, which can be compensated for with efficient fillers such as silicon carbide whiskers (SiCw). Thus, a novel hybrid composite structure is examined with the advantage of using a self‐healing mechanism and SiCw reinforcement. Tensile, tribological, and Charpy impact tests were performed to characterize the mechanical and tribological properties, which were supported with microscopic observations. Multiple experimental characterizations were performed to investigate the impact, and the ultimate tensile strength (UTS) and energy absorption capacity of the structure were shown to increase by 32% and 45%, respectively, with the addition of SiCw. The presence of self‐healing agents provides a 5% rise in UTS after enough time for healing following the collision. The structure's tribological performance is improved by 10% in wear resistance and 20% in friction coefficient. Hybrid laminated composite structure with silicon carbide whisker and self‐healing capsules. Tensile and Charpy impact tests conducted with microscopic observations Increased ultimate tensile strength and energy absorption capacity by 32% and 45%. Tribological improvement by 10% in wear resistance and 20% in friction coefficient. [ABSTRACT FROM AUTHOR]

Epoxy asphalt, a thermosetting polymer, is characterized by stable, irreversible internal chemical bonds that prevent recovery and spontaneous micro‐crack healing, unlike conventional asphalt. This study introduces a renewable nano‐modifier synthesized via esterification of carboxyl‐functionalized carbon nanotubes (CNTs‐COOH) and furfuryl alcohol (FA), termed CNTs‐FA. The successful synthesis of CNTs‐FA was confirmed through various microscopic techniques. Integrating CNTs‐FA into epoxy asphalt materials, the optimal dosage was identified as 0.05% of the total epoxy asphalt mass using tensile tests and fluorescence microscopy. Thermal reversible effects and mechanisms were further analyzed through multiple regeneration cycles using tensile properties, fluorescence microscopy, and infrared spectroscopy. The study elucidates that the thermal reversibility in epoxy asphalt is facilitated by the Diels‐Alder (DA) reaction between the conjugated diene structure in FA and the curing agent oleylamine. This research provides an effective solution to the non‐recoverability and unrepairable micro‐cracks of traditional epoxy asphalt mixtures. Highlights: CNTs‐FA was successfully prepared by esterification reaction.Using nano modification methods, introduce DA reaction into curing system.Renewable function of epoxy asphalt by DA reversible reaction. [ABSTRACT FROM AUTHOR]

In order to overcome the commercialized silicone‐based thermal interface materials' issues such as oil leakage and mechanical damage, we developed a thermoset silicone rubber matrix (SR) achieved through the condensation reaction of hydroxyl silicone oil and tetraethyl silicate. Additionally, we constructed a self‐healing and recyclable silicone rubber matrix (SCNR) by incorporating heat reversible ionic and hydrogen bonds between carboxyl and amino functionalized polydimethylsiloxane. Finally, the flexible, low oil leakage, self‐healing, and recyclable composites Al2O3/BN@SR/SCNR was prepared by adjusting the ratio of SR/SCNR and the spherical alumina and boron nitride (BN) fillers. The results indicated that with SR/SCNR mass ratio of 1/0.075 and filler content of 70 wt%, the thermal conductivity of the composite reaches 1.866 W m−1 K−1, 646% increasing over the SR/SCNR matrix. The self‐healing efficiency reaches 97% and the thermal conductivity remains essentially unchanged after being recycled for three times. The composites can be bent and twisted multiple times and still return to their original shape. Notably, the oil leakage of the Al2O3/BN@SR/SCNR composites is significantly lower than that of additive silicone composites. Therefore, the recyclable thermal conductivity composite developed in this study provides a promising solution for improving the durability of heat dissipation materials in electronic devices. [ABSTRACT FROM AUTHOR]

Lithium‐ion cells encompassing LiPF6 as the lithium salt and high‐voltage (LiNi0.5Mn1.5O4, LNMO) or high‐capacity (LiNi0.8Mn0.1Co0.1O2, NMC811) cathode materials are prone to transition metal (TM) dissolution caused by HF, whose formation is catalyzed by H2O traces. TM ions can shuttle to the anodic compartment, increasing the cell degradation rate. Accordingly, specific self‐healing strategies are helpful to develop scavengers able to eliminate HF and absorb TM ions so avoiding their shuttling. In this work, the fabrication and test of a bi‐functional, autonomous scavenging agent made of Al2O3 particles decorated is reported with chitosan. The nanometric Al2O3 core is a trap for HF by chemical bonding. The chitosan coating is acid‐sensitive, and the opening of such a capping layer is triggered in the presence of even small amounts of HF, leading to an efficient TM ion‐trapping. In addition, chitosan is biocompatible, biodegradable, and abundant, which is relevant for design‐for‐recycling scopes. With ≈200 ppm of water in the electrolyte, 12 wt% of scavenger causes, after 200 cycles at 1C, an increase of capacity retention from 73% to 88% for LNMO, and, impressively, from 46% to 84% for NMC811. This autonomous self‐healing mechanism is promising for application in next‐generation smart cells without requiring any external sensing. [ABSTRACT FROM AUTHOR]

Smart persistent organic room‐temperature phosphorescence (RTP) materials, capable of responding to microenvironmental changes, are critically important in various optoelectronic applications. However, conventional persistent RTP materials usually have not stretchability and flexibility, limiting some practical applications. This study reports a facile and one‐pot photo‐initiated copolymerization method to prepare photoactivated persistent RTP polymers with multicolored afterglow, excellent stretchability, self‐healable and recyclable properties. Impressively, the polymers can be stretched up to 500% without significant loss in RTP intensity and lifetime, and they possess a self‐healing ability with a healing efficiency of 69.6%. Utilizing these photoactivated and stretchable persistent RTP polymers, dual encryption can be achieved under UV irradiation and stretching conditions, thereby enhancing the security levels of the stored confidential information. Overall, this study represents the first example of self‐healable and recyclable stimuli‐responsive RTP materials, demonstrating their bright future for the flexible and wearable optoelectronics. [ABSTRACT FROM AUTHOR]

Oral biofilms, including pathogens such as Porphyromonas gingivalis , are involved in the initiation and progression of various periodontal diseases. However, the treatment of these diseases is hindered by the limited efficacy of many antimicrobial materials in removing biofilms under the harsh conditions of the oral cavity. Our objective is to develop a gel-type antimicrobial agent with optimal physicochemical properties, strong tissue adhesion, prolonged antimicrobial activity, and biocompatibility to serve as an adjunctive treatment for periodontal diseases. Phenylboronic acid-conjugated alginate (Alg–PBA) was synthesized using a carbodiimide coupling agent. Alg–PBA was then combined with tannic acid (TA) to create an Alg–PBA/TA hydrogel. The composition of the hydrogel was optimized to enhance its mechanical strength and tissue adhesiveness. Additionally, the hydrogel's self-healing ability, erosion and release profile, biocompatibility, and antimicrobial activity against P. gingivalis were thoroughly characterized. The Alg–PBA/TA hydrogels, with a final concentration of 5 wt% TA, exhibited both mechanical properties comparable to conventional Minocycline gel and strong tissue adhesiveness. In contrast, the Minocycline gel demonstrated negligible tissue adhesion. The Alg–PBA/TA hydrogel also retained its rheological properties under repeated 5 kPa stress owing to its self-healing capability, whereas the Minocycline gel showed irreversible changes in rheology after just one stress cycle. Additionally, Alg–PBA/TA hydrogels displayed a sustained erosion and TA release profile with minimal impact on the surrounding pH. Additionally, the hydrogels exhibited potent antimicrobial activity against P. gingivalis , effectively eliminating its biofilm without compromising the viability of MG-63 cells. The Alg–PBA/TA hydrogel demonstrates an optimal combination of mechanical strength, self-healing ability, tissue adhesiveness, excellent biocompatibility, and sustained antimicrobial activity against P. gingivalis. These attributes make it superior to conventional Minocycline gel. Thus, the Alg–PBA/TA hydrogel is a promising antiseptic candidate for adjunctive treatment of various periodontal diseases. [Display omitted] • Phenylboronic acid-conjugated alginate are synthesized and mixed with tannic acid to form hydrogel (Alg-PBA/TA). • Alg-PBA/TA hydrogel exhibits self-healing property and tissue-adhesiveness. • Alg-PBA/TA hydrogel effectively removes Porphyromonas gingivalis biofilms. • Alg-PBA/TA exhibits no notable cytotoxicity on MG-63 cells. [ABSTRACT FROM AUTHOR]

Stiff structures are generally considered detrimental to the materials' self-healing efficiency because of the rigid conformation and restricted motion of the molecular chains. However, in this study, an unexpected acceleration in self-healing was observed in a urethane network when lignosulfonate, a bio-based stiff structure with stiff benzene rings, was introduced into the polyurethane matrix. An extraordinary increase in mechanical properties was achieved with just 3 wt% lignosulfonate added to the pristine sample, including a strength increase from 16.24 MPa to 42.89 MPa and elongation at break from 390% to 602%. Importantly, this significant enhancement in mechanical properties was accompanied by a notable acceleration in healing time efficiency, which increased by up to 44% compared to the pristine sample. This unique behavior can be attributed to the mediation of lignosulfonate on the ionic bonds between lignosulfonate and the urethane segment, as well as the hydrogen bonds formed within the urethane segments. This mediation ensures ultra-high strength without compromising the self-healing capacity and opens a way for accelerating elastomers self-healing efficiency through lignosulfonate, a readily available biomass-derived material. In addition, the addition of lignosulfonates gives the elastomer some Anti-UV performance. [ABSTRACT FROM AUTHOR]

Crosslinking natural rubber (NR) and styrene butadiene rubber (SBR) composites with carbon black (CB) have been utilized in the tire tread industry. A sulfur-based lightly crosslinker can potentially enhance the self-healing capabilities of rubber. Moreover, the rubber composites were studied for non-covalent interactions between the benzene rings of SBR and CB. In this research, rubber samples were prepared, and their structure was investigated using Fourier transform infrared (FTIR), and Raman spectroscopy. The red shift in Raman spectroscopy confirmed non-covalent interaction or hydrophobic interaction between SBR and CB in NR/SBR composites exposed to CB due to environmental change. The differential scanning calorimetry (DSC) thermograms showed that NR and SBR were incompatible. Additionally, the mechanical properties of these rubber blends were enhanced as the proportion of NR increased. The maximum self-healing performance reached 40% for the formulation containing 25 phr NR and 75 phr SBR, which also saved energy with low chain end movements. Therefore, these composites could be utilized as a semi-empirical model for studying crosslinked rubber blends, specifically in the rubber tire industry. [ABSTRACT FROM AUTHOR]

Polymer‐metal complexes (PMCs) based on poly(2,2′‐bipyridine‐4,4′‐dicarboxamide‐co‐polydimethylsiloxanes) with cyclometalated di(2‐phenylpyridinato‐C2,N')iridium(III) fragments and cross‐linked by Zn2+ (Zn[Ir]‐BipyPDMSs) or Ir3+ (Ir[Ir]‐BipyPDMSs) represent flexible, stretchable, phosphorescent, and self‐healing molecular oxygen sensors. PMCs provide strong phosphorescence at λem = 595–605 nm. Zn[Ir]‐BipyPDMS with PDMS chain length of Mn = 5000 has the highest quantum yield of 9.3% and is a molecular oxygen sensor at different O2 concentrations (0–100 vol%) compared to Ir[Ir]‐BipyPDMSs. A Stern−Volmer constant is determined for Zn[Ir]‐BipyPDMS as KSV = 0.014%−1, which is similar to the reported oxygen‐sensitive iridium(III) complexes. All synthesized PMCs exhibit high elongation at break (up to 1100%) and self‐healing efficiency (up to 99%). [ABSTRACT FROM AUTHOR]

In this study, a flexible sensor is successfully fabricated using self‐healing nanocomposite hydrogels for monitoring human movement. The eco‐friendly cellulose nanocrystals (CNCs) are used as nano‐reinforcing materials, and the mechanical properties and self‐healing efficiency of the materials are improved. The self‐healing efficiency of hydrogels are realized by introducing a variety of reversible non‐covalent interactions such as hydrogen bonding, borax chelation, and metal coordination. Notably, the mechanical strength and self‐healing efficiency of these nanocomposite hydrogels can reach 2.8 MPa and 89.9%, respectively. Importantly, these self‐healing nanocomposite hydrogels have been widely used in wearable flexible sensors to achieve high sensitivity to large‐scale human movement. It is of great significance to design functional materials with good biocompatibility, sensitivity, and mechanical strength for wearable sensors. [ABSTRACT FROM AUTHOR]

Polyurethane (PU) plays a critical role in elastomers, adhesives, and self-healing materials. We selected the most commonly used aromatic isocyanates, 4,4′-methylene diphenyl diisocyanate (MDI) and tolylene-2,4-diisocyanate (TDI), and the most commonly used aliphatic isocyanates, hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), and dicyclohexylmethane-4,4′-diisocyanate (HMDI), as raw materials, combined with polytetramethylene ether glycol (PTMG) and 1,4-butanediol (BDO) to successfully synthesize five PU materials. The effects of isocyanate structure on polymerization rate, hydrogen bonding, thermal properties, phase separation, wettability, self-healing performance, adhesion, and mechanical properties were systematically investigated. The results show that isocyanates with higher symmetry facilitate hydrogen bonding, but excessive flexibility and crystallinity may inhibit its formation. MDI-based PU exhibits the highest hydrogen bonding index (HBI) of 4.10, along with the most distinct phase separation and the highest tensile strength of 23.4 MPa. HMDI-based PU demonstrates the best adhesion properties, with the highest lap shear strength of 7.9 MPa, and also exhibits excellent scratch healing ability. IPDI-based PU shows good self-healing performance, recovering 88.7% of its original tensile strength and 90.6% of its original lap shear strength after heating at 80 °C for 24 h. Furthermore, all the samples can be reprocessed by melt or solution methods, showing excellent recyclability. [ABSTRACT FROM AUTHOR]

Here, we report a reprocessible, reusable, self-healing, and form-switching polymeric adsorbent for remediating fluorinated pollutants in water. The copolymer hydrogel is designed to contain fluorophilic segments and cationic segments to induce strong binding with perfluorinated pollutants. The sorption performance reveals rapid and quantitative removal of these pollutants, driven by the synergistic effect of fluorophilic and electrostatic interaction. Importantly, a disulfide-containing dynamic crosslinker plays a crucial role in imparting multifunctionality. This enables self-healing by the restoration of crosslinks at the cut surfaces by disulfide exchange reactions and allows for the repeated use of the adsorbent via multiple adsorption–desorption cycles. Furthermore, the adsorbent is reprocessible by cleaving the crosslinks to afford linear copolymers, which can be repolymerized into a hydrogel network on demand. Also, form-switching capability is showcased through the aqueous self-assembly of linear copolymers into a fluorinated micelle, serving as another form of adsorbent for pollutant removal. [ABSTRACT FROM AUTHOR]

In the pursuit of sustainable hydrogen production via water electrolysis, paramount importance of electrocatalyst stability emerges as a defining factor for long‐term industrial viability. A thorough understanding and enhancement of stability not only ensure extended catalyst lifetimes but also pave the way for consistent and efficient hydrogen generation. This review focuses on the pivotal role of stability in determining the practical viability of oxygen evolution electrocatalysts (OECs) for large‐scale applications in water electrolysis for hydrogen production. The paper explores the pivotal role of stability over initial activity, citing examples and hypothetical scenarios. First, figures of merits for stability evaluation of the electrocatalyst are explained along with the available benchmarking protocols for stability evaluation. Further, the text delves into various strategies that can enhance the stability of the electrocatalyst which include self‐healing/regeneration pathway, oxygen evolution reaction (OER) mechanism optimization to achieve highly stable OER and stabilization of active metals atoms within the electrocatalyst to inhibit dissolution as a way forward for industrial application. The interplay of stability, activity, and cost is also explained to suit the industrial application of the electrocatalyst. Lastly, it outlines challenges, prospects, and future directions, presenting a guide for advancing OECs in the hydrogen generation landscape. [ABSTRACT FROM AUTHOR]

In this study, we report the development of a hybrid polymer material comprising poly(butyl methacrylate) and titania, which exhibits the three key elements of visible-light transparency, UV shielding, and self-healing. Nanodispersion of titania in the polymers was achieved using the sol – gel method using titanium propoxide as the raw material. Furthermore, by adding tetrabutylphosphonium chloride, an ionic liquid, we suppressed visible light absorption due to charge transfer between poly(butyl methacrylate) and titania, resulting in enhanced visible light transmittance. An approach involving crosslinking points comprising Diels – Alder functional groups was used to heal scratches in the hybrid material at 75°C for 30 min. Dynamic viscoelastic measurements and microscopic observations were conducted to investigate the self-healing mechanism. These findings suggested that this phenomenon occurred through the fluidization of the polymer matrix and the recombination reaction of the crosslinking points, which comprise Diels – Alder and titania. The development of intelligent materials with combined transparency, UV protection, and self-healing capabilities provides potential avenues for future research to enhance and broaden their versatile characteristics for widespread applications. [ABSTRACT FROM AUTHOR]

This article provides a brief description of microcapsule self-healing technique and its potential use in concrete structures. Because concrete is readily available and reasonably priced, it is widely utilised in the building industry globally, despite its susceptibility to the formation of cracks. The longevity and security of concrete buildings are greatly impacted by the existence of cracks and other deterioration occurring during the course of their use. Through the encapsulation of healing material inside microcapsules, which shows rupture upon cracking in cement-based materials, the microcapsule exhibits promise in accomplishing self-healing and increasing durability and strength in the structures. The article first explains the basic ideas behind the science of microcapsule self-healing and then looks at different ways to prepare microcapsules. It also looks into how adding microcapsules affects the basic characteristics of the concrete building. A summary of the efficiency and self-healing mechanisms of microcapsules is also provided. Highlights: The article explains the advantages of the microcapsule self-healing method in concrete. Preparation method and intrinsic properties of different microcapsules are discussed. Different self-healing measurement techniques in cement-based materials are discussed. The study examines the qualitative aspects of various self-healing methods. Looks into how adding microcapsules affects the properties of cementitious materials. [ABSTRACT FROM AUTHOR]

Recent decades have witnessed the increasing use of soil mixing technology to construct cut-off walls for groundwater control or underground pollutant containment. The strength and permeability of soil mix columns deteriorate considerably when subjected to chemical, mechanical and environmental stresses, leading to the need for repair of crack-originated damage. The development of self-healing grouts could provide more resilient and sustainable soil mix cut-off walls. In this study, for the first time, self-healing soil mix columns incorporating reactive magnesium oxide pellets were developed. The magnesium oxide-based cementitious grout was mixed with a sand soil using a laboratory-scale auger, and the embedded magnesium oxide pellets were ruptured upon cracking, producing expansive healing products due to hydration and carbonation, which can significantly fill the crack volume. The effects of magnesium oxide on the grout and soil mix samples were investigated in terms of both fresh and hardened properties. In addition, the self-healing performance was evaluated by examining permeability recovery and crack closure, and the microstructure and morphology of the magnesium oxide pellets and healing products were analysed. The results demonstrate the great potential of reactive magnesium oxide pellets as a self-healing agent for soil mix cut-off wall materials. [ABSTRACT FROM AUTHOR]

When asphalt pavement is in practical use, it is prone to cracking and other diseases due to the long-term effects of load and climate and the restricted self-healing properties of the asphalt material. In order to improve the properties and durability of asphalt pavement, we introduced disulfide bonds into polyurethane (PU) in this study. We prepared polyurethane-modified asphalt (PUA) containing dynamic disulfide covalent bonds using polytetrahydrofuran (PTMG), polyethylene adipate (PEA), and hydroxyl-terminated polybutadiene (HTPB) as soft segments. Subsequently, the rheological properties, healing performance, and microstructure of the PUA were studied. The results indicated that the PU with disulfide bonds was integrated into the asphalt and had good dispersity. A cross-linked network structure formed between them. PUA with HTPB as the soft segment had excellent high-temperature deformation and low-temperature cracking resistance and a prominent advantage in durability. In comparison, PUA synthesized with PEA had better high-temperature performance and fatigue resistance, and PUA synthesized with PTMG had considerable low-temperature properties and stability. The disulfide bonds had a positive impact on the high-temperature performance, aging resistance, and healing properties of PUA through constant dynamic exchange and topological rearrangement effects. This study provides a reference for the preparation of PUA with ideal self-healing ability and has instructive significance for the selection of soft segment materials for synthesizing PUA. [ABSTRACT FROM AUTHOR]

This research aims to investigate the self-healing of low-temperature cracks in asphalt mixture using semicircular bending tests at different modes of fracture. In this research, samples are fabricated with a 12.5 mm nominal size aggregate and PG58-22 binder. All aged and unaged asphalt samples are subjected to 10 cooling cycles. Also, the resting time between cooling cycles is applied to self-healed samples. The results show that cooling cycles significantly reduce the fracture energy and applying the resting time increases the healing, cracking resistance, and balanced cracking indices. In addition, the most effective of self-healing is observed at fracture mode II. [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]

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. [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]