•Novel ZIF decorated HA nanocontainer with stimulus responsiveness were developed.•Encapsulation of Phen in nanocontainer can be easily achieved by one-step method.•Localized corrosion can be timely ...and precisely located and reported.•Coating exhibits barrier, corrosion self-diagnosing and self-repairing traits.
Polymeric coatings with long life, strong environmental adaptability and high durability are of great significance for practical applications. This work presents a facial strategy to construct a smart nanocomposite coating with excellent shielding, corrosion self-diagnosing and self-repairing functions by integrating nanocontainers into epoxy resin. The nanocontainers were synthesized through decorating the hydroxyapatite sheets with zeolitic imidazolate frameworks (HA-ZIF), which were employed to encapsulate corrosion probe (Phenanthroline, Phen). With the occurrence of localized corrosion, Phen molecules could be timely released and reacted with the metal ions to form conspicuous red color at damaged sites, achieving real time corrosion diagnosing function. Given the stimulus responsive property of ZIF, the corrosion propagating process can be significantly inhibited by the released benzimidazole. As contrast of the traditional nanocontainers applied in anticorrosion coating, the inhibitors were used directly to synthesis the HA-ZIF nanocontainer rather than subsequent loading, which greatly improved inhibitors content in nanocontainers. Moreover, the impermeability of composite coating has been remarkably enhanced by the presence of HA sheets, ensuring the long-term protective performance. Importantly, the integrating multi functions in one coating is realized in the ingeniously designed nanocontainers. It is envisioned that the facial and feasible strategy provides insights in improving the longevity, functionality and reliability of protective coatings.
Infrared transmitting materials (IRTMs) are prone to mechanical and corrosion damage during long‐time exposure to harsh outside environments. However, conventional IRTMs frequently lack ...self‐repairability that limit their lifespan. To address the limitation, thioctic acid‐based epoxy resins (TAEs) are developed from natural thioctic acid and commercial epoxy monomers. The double ring‐opening polymerization (ROP) reactions of thioctic acid and epoxy groups result in dual dynamic covalent bonds with varying bond energies containing relatively weak disulfide bonds and strong ester bonds. As compared with conventional covalent adaptable networks (CANs) that present rapid creep properties when heated, TAEs maintain their geometric stability during rapid self‐repairing at a mild temperature of 80 °C by enhancing network integrity through stable ester crosslinking points. The feature renders TAEs self‐repairing capability while maintaining precise geometrical dimensions, which is suitable for infrared transmitting devices. On the other hand, TAEs exhibit high near‐infrared transmittance (>80%). Therefore, TAEs with self‐repairability and high infrared transmittance demonstrate they can be used as superior polymeric IRTM.
Covalent adaptable networks with dual dynamic covalent bonds, termed thioctic acid‐based epoxy resins (TAEs), are developed. Among TAEs, the relatively weak disulfide bonds provide self‐healing properties and the strong β‐hydroxyester bonds endow TAEs with geometric stability. Combined with their tunable mechanical properties, minimal curing shrinkage, and robust chemical stability, TAEs show great potential for application in infrared‐transmitting polymeric materials.
A new generation of ultrathin, functional, self-repairing graphene-based coatings is emerging. Such coatings have excellent potential for corrosion protection owing to the superior mechanical ...properties, high specific aspect ratio and impermeability of graphene. This paper summarizes the barrier mechanisms, existing questions, and limitations pertaining to ultrathin graphene coatings. The main factors affecting the corrosion resistance of graphene-based composite coatings, including their orientation, dispersion, size, content, and conductivity, are systematically discussed. The advantages and self-repairing mechanisms of smart graphene-based composite coatings are also highlighted. The challenges associated with graphene and graphene-based composite coatings for metal protection are discussed.
Bone marrow (BM)‐resident hematopoietic stem and progenitor cells (HSPCs) are often activated following bacterial insults to replenish the host hemato‐immune system, but how they integrate the ...associated tissue damage signals to initiate distal tissue repair is largely unknown. Here, we show that acute gut inflammation expands HSPCs in the BM and directs them to inflamed mesenteric lymph nodes through GM–CSFR activation for further expansion and potential differentiation into Ly6C+/G+ myeloid cells specialized in gut tissue repair. We identified this process to be mediated by Bacteroides, a commensal gram‐negative bacteria that activates innate immune signaling. These findings establish cross‐organ communication between the BM and distant inflamed sites, whereby a certain subset of multipotent progenitors is specified to respond to imminent hematopoietic demands and to alleviate inflammatory symptoms.
Synopsis
How the hematopoietic system responds to and manages infiltrating microbial signals under pathophysiological conditions has remained unclear. Here, a DSS‐induced acute colitis model was used to reveal how hematopoietic stem cells and progenitor cells (HSPCs) relay microbiota signals to promote tissue repair.
Acute gut inflammation causes expansion and myeloid‐directed differentiation of bone marrow (BM) HSPCs, some of which migrate to inflamed mesenteric lymph nodes.
Gut‐resident Bacteroidesdirects BM multipotent progenitor expansion and migration towards mesenteric lymph nodes via GM–CSF and innate immune signaling.
Ly6C+/G+ cells with an immunosuppressive phenotype accumulate both in the mesenteric lymph node and gut to promote tissue repair.
Depletion of Ly6C+/G+ cells with a neutralizing antibody exacerbates DSS‐induced colitis while the adoptive transfer of Ly6C+/G+ containing MLN cells alleviates gut tissue damage.
Acute inflammation in the mouse gut causes Bacteroides to direct the expansion and migration of BM HSPCs to mesenteric lymph nodes through activation of GM–CSF.
Epoxidized natural rubber (ENR) crosslinked using borax, which exhibits self‐healing and self‐repairing properties, is successfully developed. The crosslink formation of ENR by using borax under ...neutral and alkaline conditions is investigated. Fourier transform infrared spectroscopy (FTIR) shows that the borate–ester bond is formed in ENR prepared under both neutral and alkaline conditions, whereas boron nuclear magnetic resonance (11B‐NMR) results exhibit that the ENR prepared under alkaline conditions more actively forms crosslink networks with borax. Moreover, the crosslink density and gel content increase significantly with the presence of borax in alkaline conditions. The crosslink density and gel content of ENR with 10 phr borax are higher by 155% and 36%, respectively, than those of neat ENR. Furthermore, the formation of the crosslinking ENR by borax enhances self‐healing and self‐repairing properties. The healing efficiency significantly increases from 1.09% to 85.90%, when ENR is developed under alkaline conditions with 30 phr borax. These results represent the first successful demonstration of the efficient use of borax as a crosslinker in ENR, which exhibits its promising self‐healing and self‐repairing properties under atmospheric conditions without the need for external stimuli. The ENR prepared in this work holds great promise for various self‐healing rubber applications.
The efficient use of borax as a crosslinker to develop epoxidized natural rubber (ENR) with self‐healing and self‐repairing properties under atmospheric conditions without the need of external stimuli is successfully demonstrated. ENR prepared under alkaline conditions more potentially forms crosslinked network with borax and holds great promise for various self‐healing rubber applications.
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•The coating composed of agglomerate-strengthened particle-capsules with ceramic binder.•The coating exhibited stable super-repellency after 500 cycles 250 g Taber abrasion.•The ...coating maintained superamphiphobictiy even after comprehensive harsh conditions.•This particle-capsules can release fluorinated nanoparticles for self-repairing.
Superamphiphobic surfaces that can keep surface clean even in severe oil pollution environments are attractive for many practical applications. Existing surfaces could achieve good environmental durability, but rarely anyone has demonstrated that coatings with mechanical robustness and superamphiphobicity were fabricated by simple fabrication processes. In this work, a new design of component phase separation on nanoparticle-capsules is proposed to generate durable superamphiphobic coatings by spray-coating the suspension of fluorinated nanoparticle powders and ceramic binders. During the process of film formation, the micro/nano composite structures appear on the surface by the stacking of agglomerates and nanoparticles. Meanwhile, the particles in the suspension can be reunited to produce plentiful particle-agglomerates in longitudinal direction driven by the difference of surface tension. And the agglomerates acted as particle-capsules are able to release the embedded fluorinated silica nanoparticles to the surface to regenerate superamphiphobicity instantaneously during physical wear. Moreover, the coatings are durable against physical abrasion of 500 Taber abrasion cycles under a load of 250 g, maintaining super-repellency to oils under comprehensive harsh conditions such as oil immersion, oil mist impact, and sand water stirring. This strategy is supposed to offer a new insight to development durable superamphiphobic coatings that can endure harsh operation environments for mechanical abrasion and chemical erosion.
Recovery from damage in materials helps extend their useful lifetime and of devices that contain them. Given that the photodamages in HaP materials and based devices are shown to recover, the ...question arises if this also applies to mechanical damages, especially those that can occur at the nanometer scale, relevant also in view of efforts to develop flexible HaP‐based devices. Here, this question is addressed by poking HaP single crystal surfaces with an atomic force microscope (AFM) tip under both ultra‐high vacuum (UHV) and variably controlled ambient water vapor pressure conditions. Sequential in situ AFM scanning allowed real‐time imaging of the morphological changes at the damaged sites. Using methylammonium (MA) and cesium (Cs) variants for A‐site cations in lead bromide perovskites, the experiments show that nanomechanical damages on methylammonium lead bromide (MAPbBr3) crystals heal an order of magnitude faster than Cs‐based ones in UHV. However, surprisingly, under ≥40% RH conditions, cesium lead bromide (CsPbBr3) shows MAPbBr3‐like fast healing kinetics. Direct evidence for ion solvation on CsPbBr3 is presented, leading to the formation of a surface hydration layer. The results imply that moisture improves the ionic mobility of degradation components and leads to water‐assisted improved healing, i.e., repair of nanomechanical damages in the HaPs.
Healing damage in halide perovskites (HaPs) is a fascinating property that can help extend the functional lifetime of devices. A novel approach is used to study mechanical damages and their recovery kinetics with atomic force microscopy operated in both ultra‐high vacuum and controlled humidity conditions. Remarkably, this study observes that moderate humidity conditions aid healing in the HaPs.
Covalent organic frameworks (COFs), with their inherent merits of specific pore size and uniform channels, have been extensively employed to produce nanofiltration (NF) membranes. However, COF-based ...NF towards precise separations, especially for ion separations, are often unsatisfying due to the intercrystalline defects in selective layers. Herein, a pressure-modulated synthesis method has been explored to prepare crystalline and defect-free COF membranes on seeded substrates for fast NF. Amine and aldehyde solutions are separately placed with a level interval to create vertical hydraulic pressure, which can regulate the mobility of the amine monomers and thus results in the self-repairing of defects in the COF planes and remediation of intercrystalline gaps. The abundant nucleation sites on seeded substrates promote the confined growth of COF crystallites in top layers, leading to an ultrathin selective layer with improved permeance. The resultant COF membrane shows tight methyl orange (~90.4%) and Na2SO4 (~63.6%) rejections with a pronounced water permeance of up to ~44.2 L m−2 h−1 bar−1, which is ~2–10 times higher than other NF membranes with similar rejections. This pressure-modulated synthetic strategy establishes not only the self-repairing synthesis of COFs but also the controllable preparation of defect-free COF-based NF membranes, thus enabling precise and fast separation of molecules and ions.
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•A pressure-modulated synthesis method was built up to fabricate highly crystalline COF nanofiltration membranes.•The external pressure precisely regulates the mobility of precursors and eliminates the nonselective intercrystalline gaps.•Abundant nucleation sites promote the conformal growth of COF crystals.•The membranes exhibit excellent water permeance and rejections to objects with a size above 1.1 nm.
Sugar moieties were incorporated into cross‐linked polyurethane (PUR) networks in an effort to achieve self‐repairing in the presence of atmospheric carbon dioxide (CO2) and water (H2O). When ...methyl‐α‐D‐glucopyranoside (MGP) molecules are reacted with hexamethylene diisocyanate trimer (HDI) and polyethylene glycol (PEG) to form cross‐linked MGP‐polyurethane (PUR) networks, these materials are capable of self‐repairing in air. This process requires atmospheric amounts of CO2 and H2O, thus resembling plant behavior of carbon fixation during the photosynthesis cycle. Molecular processes responsible for this unique self‐repair process involve physical diffusion of cleaved network segments as well as the formation of carbonate and urethane linkages. Unlike plants, MGP‐PUR networks require no photo‐initiated reactions, and they are thus capable of repair in darkness under atmospheric conditions.
Self‐repairing materials were obtained by reacting sugar moieties with hexamethylene diisocyanate trimer and polyethylene glycol to form cross‐linked MGP‐polyurethane networks. The repair process requires atmospheric amounts of CO2 and H2O, thus resembling plant behavior of carbon fixation during photosynthesis.
Robust liquid-repellent LGSS with superior anti-fouling and self-repairing properties was fabricated through spraying the SH-HMS on various substrates followed by the covalently grafted of ...vinyl-terminated PDMS via thiol-ene click reaction.
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The development of robust, stain-resistant, and self-healing liquid-repellent surfaces is a common aspiration of both consumer and industrial applications, but the existing methods suffer from limitations, such as complicated procedures, weak mechanical durability and substrate dependency. In this work, a lubricant-grafted slippery surface (LGSS) was prepared by grafting vinyl-terminated polydimethylsiloxane (Vi-PDMS) onto various substrates coated with sulfhydryl-modified hollow mesoporous silica (SH-HMS) through a thiol-ene click reaction. The uniform and intact lubricant layer can effectively decrease the absorption of the polysaccharide and protein, exhibiting superior antifouling properties. Notably, the hollow structure of SH-HMS could significantly increase the oil grafting capacity of the slippery surface from 0.013 g/cm2 to 0.027 g/cm2 compared with the surface constructed by solid silica. By virtue of the strong covalent bond forces between the lubricant oil and surfaces, the obtained LGSS exhibited robust liquid repellency when subjected to high/low temperature, ultraviolet irradiation and water impact. Moreover, the liquid-repellent LGSS exhibited good self-repairing performance owing to the directional migration of the Vi-PDMS chain segment from the hollow capsule to the surface through the mesoporous channels under heating treatment. Therefore, such a newly developed strategy for constructing liquid-repellent coatings on various substrates with self-repairing properties has the potential to promote the advancement of interfacial antifouling materials and exhibit tremendous potential for consumer and industrial applications.
