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[EN] The performance of the Mn-NaWO/SiO catalyst for oxidative coupling of methane (OCM) has been ascribed to crystalline phases that are not present at reaction temperatures (>700 °C). The evolution of W and Mn sites structure was monitored via in situ TPO-XRD, -Raman, and -XANES spectroscopies. TPO-XRD shows that the crystalline phases identified on the Mn-NaWO/SiO, NaWO/SiO, and WO/SiO catalysts at room temperature do not exist at relevant OCM temperatures. The γ → β → α-WO, α → β-cristobalite, and cubic → orthorhombic → molten-NaWO phase transitions occur upon heating. TPO-Raman spectra show that the bond order of W sites with octahedral (O) and tetrahedral (T) symmetry changes during the δ → γ → β → α-WO and cubic → orthorhombic → molten-NaWO transitions, respectively. TPO-XANES spectra show that bond order changes are due to distortion degree variations because all samples preserve essentially W valence and O-Mn sites are always present on Mn-NaWO/SiO catalyst. Steady-state OCM tests show that O-W sites are inactive and T-W sites are less distorted and more active towards methane activation in the presence of O-Mn sites., This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES)- Finance Code 001. We acknowledge the Brazilian Synchrotron Light Laboratory (LNLS) at the National Center for Research in Energy and Materials (CNPEM) for making available beam-time under proposal XAFS2-20190152. C.A.O-B gratefully acknowledge the financial support of the CAPES (process No. 88887.368574/2019-00) and Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) (process No. E-26/200.785/2019) for scholarship grant. The Raman system was acquired with Spanish Ministry grant EQC2018-004839-P and co-funded by CSIC.

Novel approaches for N- and O-desulfonylation under room temperature (rt) and transition-metal-free conditions have been developed. The first methodology involves the transformation of a variety of N-sulfonyl heterocycles and phenyl benzenesulfonates to the corresponding desulfonylated products in good to excellent yields using only KOtBu in dimethyl sulfoxide (DMSO) at rt. Alternately, a visible light method has been used for deprotection of N-methyl-N-arylsulfonamides with Hantzsch ester (HE) anion serving as the visible-light-absorbing reagent and electron and hydrogen atom donor to promote the desulfonylation reaction. The HE anion can be easily prepared in situ by reaction of the corresponding HE with KOtBu in DMSO at rt. Both protocols were further explored in terms of synthetic scope as well as mechanistic aspects to rationalize key features of desulfonylation processes. Furthermore, the HE anion induces reductive dehalogenation reaction of aryl halides under visible light irradiation. Fil: Heredia, Micaela Denise. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina Fil: Guerra, Walter Damián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina Fil: Barolo, Silvia Maricel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina Fil: Fornasier, Santiago J.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina Fil: Rossi, Roberto Arturo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina Fil: Budén, María E.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina

We describe the clinical course of a 65-year-old male patient who suffered from hydrocarbon-induced myelodysplasia and was successfully treated with the thrombopoietin receptor agonist (TPO-RA), romiplostim. Myelodysplastic syndromes (MDS) are characterized by ineffective hematopoiesis, cytopenias, and increased risk of leukemic transformation. Here, we present a clinical vignette of MDS-associated thrombocytopenia refractory to first-line drugs as well as the TPO-RA, eltrombopag. To date, romiplostim is an U.S. Food and Drug Administration (FDA)-approved drug for idiopathic thrombocytopenic purpura and thrombocytopenia secondary to liver disease. Of note, currently the FDA advises against its use in MDS based on previous long-term safety concerns. Since the therapeutic options for thrombocytopenia in MDS patients are sparse, repurposing and reassessing romiplostim in this setting have been the focus of recent studies. At the time of writing, no published double-blind randomized clinical trials have conducted a head-to-head comparison between romiplostim and eltrombopag in thrombocytopenic MDS patients. To the best of our knowledge, for a thrombocytopenic patient in the setting of MDS, this is the first documented report of refractory clinical response after a 2-year use of eltrombopag in which replacement of treatment with romiplostim resulted in sustained physiological counts of thrombocytes within four weeks.

Using a new method for measuring the molecular ratio (R) of inhalation to exhalation, we investigated the effect of high fraction of inspired oxygen (FIO2) on oxygen consumption (VO2), carbon dioxide generation (VCO2), and respiratory quotient (RQ) in mechanically ventilated rats. Twelve rats were equally assigned into two groups by anesthetics: intravenous midazolam/fentanyl vs. inhaled isoflurane. R, VO2, VCO2, and RQ were measured at FIO2 0.3 or 1.0. R error was ± 0.003. R was 1.0099 ± 0.0023 with isoflurane and 1.0074 ± 0.0018 with midazolam/fentanyl. R was 1.0081 ± 0.0017 at an FIO2 of 0.3 and 1.0092 ± 0.0029 at an FIO2 of 1.0. There were no differences in VCO2 among the groups. VO2 increased at FIO2 1.0, which was more notable when midazolam/fentanyl was used (isoflurane-FIO2 0.3: 15.4 ± 1.1; isoflurane-FIO2 1.0: 17.2 ± 1.8; midazolam/fentanyl-FIO2 0.3: 15.4 ± 1.1; midazolam/fentanyl-FIO2 1.0: 21.0 ± 2.2 mL/kg/min at STP). The RQ was lower at FIO2 1.0 than FIO2 0.3 (isoflurane-FIO2 0.3: 0.80 ± 0.07; isoflurane-FIO2 1.0: 0.71 ± 0.05; midazolam/fentanyl-FIO2 0.3: 0.79 ± 0.03; midazolam/fentanyl-FIO2 1.0: 0.59 ± 0.04). R was not affected by either anesthetics or FIO2. Inspired 100% O2 increased VO2 and decreased RQ, which might be more remarkable when midazolam/fentanyl was used.

This case series reviews four critically ill patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) [coronavirus disease 2019 (COVID-19)] suffering from pneumatosis intestinalis (PI) during their hospital admission. All patients received the biological agent tocilizumab (TCZ), an interleukin (IL)-6 antagonist, as an experimental treatment for COVID-19 before developing PI. COVID-19 and TCZ have been independently linked to PI risk, yet the cause of this relationship is unknown and under speculation. PI is a rare condition, defined as the presence of gas in the intestinal wall, and although its pathogenesis is poorly understood, intestinal ischemia is one of its causative agents. Based on COVID-19's association with vasculopathic and ischemic insults, and IL-6's protective role in intestinal epithelial ischemia–reperfusion injury, an adverse synergistic association of COVID-19 and TCZ can be proposed in the setting of PI. To our knowledge, this is the first published, single center, case series of pneumatosis intestinalis in COVID-19 patients who received tocilizumab therapy.

Chagas disease is caused by infection with the protozoan parasite Trypanosoma cruzi (T. cruzi), an intracellular pathogen that causes significant morbidity and death among millions in the Americas from Canada to Argentina. Current therapy involves oral administration of the nitroimidazole benznidazole (BNZ), which has serious side effects that often necessitate cessation of treatment. To both avoid off-target side effects and reduce the necessary dosage of BNZ, we packaged the drug within poly(ethylene glycol)-block-poly(propylene sulfide) polymersomes (BNZ-PSs). We show that these vesicular nanocarriers enhanced intracellular delivery to phagocytic cells and tested this formulation in a mouse model of T. cruzi infection. BNZ-PS is not only nontoxic but also significantly more potent than free BNZ, effectively reducing parasitemia, intracellular infection, and tissue parasitosis at a 466-fold lower dose of BNZ. We conclude that BNZ-PS was superior to BNZ for treatment of T. cruzi infection in mice and that further modifications of this nanocarrier formulation could lead to a wide range of custom controlled delivery applications for improved treatment of Chagas disease in humans.

Background Cardiac arrest (CA) can induce oxidative stress after resuscitation, which causes cellular and organ damage. We hypothesized that post‐resuscitation normoxic therapy would protect organs against oxidative stress and improve oxygen metabolism and survival. We tested the oxygen‐sensitive reactive oxygen species from mitochondria to determine the association with hyperoxia‐induced oxidative stress. Methods and Results Sprague–Dawley rats were subjected to 10‐minute asphyxia‐induced CA with a fraction of inspired O 2 of 0.3 or 1.0 (normoxia versus hyperoxia, respectively) after resuscitation. The survival rate at 48 hours was higher in the normoxia group than in the hyperoxia group (77% versus 28%, P P P P Conclusions Post‐resuscitation normoxic therapy attenuated the oxidative stress in multiple organs and improved post‐CA organ injury, oxygen metabolism, and survival. Additionally, post‐CA hyperoxia increased the mitochondrial reactive oxygen species and activated the antioxidation system.

microRNAs are short noncoding RNAs that regulate protein expression posttranscriptionally. We previously showed that miR-155 promotes effector CD8+ T-cell responses. However, little is known about the regulation of miR-155 expression. Here, we report that antigen affinity and dose determine miR-155 expression in CD8+ T cells. In B16 tumors expressing a low-affinity antigen ligand, tumor-specific infiltrating CD8+ T cells showed variable miR-155 expression, whereby high miR-155 expression was associated with more cytokine-producing cells and tumor control. Moreover, anti–PD-1 treatment led to both increased miR-155 expression and tumor control by specific CD8+ T cells. In addition, miR-155 overexpression enhanced exhausted CD8+ T-cell persistence in the LCMV cl13 chronic viral infection model. In agreement with these observations in mouse models, miR-155 expression in human effector memory CD8+ T cells positively correlated with their frequencies in tumor-infiltrated lymph nodes of melanoma patients. Low miR-155 target gene signature in tumors was associated with prolonged overall survival in melanoma patients. Altogether, these results raise the possibility that high miR-155 expression in CD8+ tumor-infiltrating T cells may be a surrogate marker of the relative potency of in situ antigen-specific CD8+ T-cell responses.

Natural materials provide an increasingly important role model for the development and processing of next-generation polymers. The velvet worm Euperipatoides rowelli hunts using a projectile, mechanoresponsive adhesive slime that rapidly and reversibly transitions into stiff glassy polymer fibers following shearing and drying. However, the molecular mechanism underlying this mechanoresponsive behavior is still unclear. Previous work showed the slime to be an emulsion of nanoscale charge-stabilized condensed droplets comprised primarily of large phosphorylated proteins, which under mechanical shear coalesce and self-organize into nano- and microfibrils that can be drawn into macroscopic fibers. Here, we utilize wide-angle X-ray diffraction and vibrational spectroscopy coupled with in situ shear deformation to explore the contribution of protein conformation and mechanical forces to the fiber formation process. Although previously believed to be unstructured, our findings indicate that the main phosphorylated protein component possesses a significant β-crystalline structure in the storage phase and that shear-induced partial unfolding of the protein is a key first step in the rapid self-organization of nanodroplets into fibers. The insights gained here have relevance for sustainable production of advanced polymeric materials.

Starting from experimental macro-rheological data, we develop a fitting protocol that succeeded in the separation of the overlapping relaxation phenomena in the dissipative regime for a set of intrinsic healing polymers healing most effectively near their glass transition temperature T g . To allow for a proper deconvolution, the rheological master curves are converted to a relaxation spectrum (H(τ)) and this is fitted using an optimized mechanical model, e.g. the Maxwell-Weichert model. The deconvolution of overlapping segmental mobility and reversible interactions is successfully demonstrated for a set of polyimide and polyamide polymers containing none, one and two reversible dynamic features near-T g . Through the fitting parameters, the relaxation timescale of each feature and their apparent process enthalpies are obtained. The quantitative data obtained using the fitting protocol are then compared to macroscopic healing results. As a result, a clear correspondence between the energy stored by the system to accomplish reversible (e.g. H-bonds, π-π) and chain interdiffusion relaxation transitions and the healing efficiency of such polymers are obtained. The implementation of this protocol allows for a clearer identification of the relevant mechanisms in self-healing polymers and paves the way for the development of more efficiently healable polymeric systems.

Despite recent advances in the management of post–cardiac arrest syndrome (PCAS), the survival rate, without neurologic sequelae after resuscitation, remains very low. Whole-body ischemia, followed by reperfusion after cardiac arrest (CA), contributes to PCAS, for which established pharmaceutical interventions are still lacking. It has been shown that a number of different processes can ultimately lead to neuronal injury and cell death in the pathology of PCAS, including vasoconstriction, protein modification, impaired mitochondrial respiration, cell death signaling, inflammation, and excessive oxidative stress. Recently, the pathophysiological effects of inhaled gases including nitric oxide (NO), molecular hydrogen (H2), and xenon (Xe) have attracted much attention. Herein, we summarize recent literature on the application of NO, H2, and Xe for treating PCAS. Recent basic and clinical research has shown that these gases have cytoprotective effects against PCAS. Nevertheless, there are likely differences in the mechanisms by which these gases modulate reperfusion injury after CA. Further preclinical and clinical studies examining the combinations of standard post-CA care and inhaled gas treatment to prevent ischemia–reperfusion injury are warranted to improve outcomes in patients who are being failed by our current therapies.

The effects of the soft block fraction and H-bond state in thermoplastic polyurethanes on autonomous entropy-driven scratch closure and barrier restoration are studied. To this aim, comparable polyurethanes with different segmentation states are applied as organic coatings on plain carbon steel plates, scratched under very well-controlled conditions, and the scratch closure and sealing kinetics are studied in detail. The scratch closure is measured optically, while the barrier restoration is probed by the accelerated cyclic electrochemical technique (ACET). Scratch closure, attributed to entropic elastic recovery (EER), is followed in a marked two-step process by barrier restoration governed by local viscous flow and the state of the interfacial hydrogen bonding. Polyurethanes with a lower soft phase fraction lead to a higher urea/urethane ratio, which in turn influences the healing efficiency of each healing step. Interestingly, softer polyurethanes leading to efficient crack closure were unable to sufficiently restore barrier properties. The present work highlights the critical role of the soft/hard block and urea/urethane H-bond state content on crack closure and barrier restoration of anticorrosive organic coatings and points at design rules for the design of more efficient corrosion-protective self-healing polyurethanes.

Introduction: Hyperoxia can induce oxidative stress resulting in organ injuries after cardiac arrest (CA). Mitochondrial reactive oxygen species (ROS) are key to understanding its mechanism, however the augmentation of oxygen-sensitive ROS generation caused by CA ( Fig 1 ) has not been well described. Methods: Rats were assigned into: 1) sham with normoxia, 30% O2; 2) sham with hyperoxia, 100% O2; 3) CA with normoxia; and 4) CA with hyperoxia (n=15 for each group). CA was induced by 10-minute asphyxia and CPR was delivered. Neurological deficit score (NDS), histological lung injury score (LIS), survival time were obtained from the CA groups. Carbonyl protein as an oxidative stress indicator was measured at 2 hrs after resuscitation. H2O2 generation from isolated mitochondria were measured ex vivo at a normoxic and hyperoxic condition set up with nitrogen and air saturated medium. Results: Between the CA groups, the normoxia group had a higher 48hr-survival rate (77%), lower NDS (359±140), and lower LIS (4.3±2.9) compared to those (28%, 452±85, 14±2, respectively) of the hyperoxia group (p Conclusions: The normoxic therapy may attenuate organ damage and improve survival of CA. The reduction of augmented mitochondrial ROS generation, which is oxygen-sensitive, would be an important mechanism and therapeutic target of post-CA care.

Earlier studies on cerium-loaded naturally occurring silica microparticles (i.e., diatomaceous earth) demonstrated the potential to efficiently protect small scratches in epoxy-coated AA2024-T3 panels during relatively short immersion times. The current work investigates the potential of such inhibitor-loaded microparticles to protect wide and deep scribes (up to 1 mm wide) in long-time immersion testing and during cyclic (wet/dry) conditions. For this, cerium nitrate and 2,5-dimercaptothiadiazole (DMTD) were used as inorganic and organic corrosion inhibitors. The corrosion protection was evaluated using a hyphenated real-time optics/electrochemistry method and two individual local techniques measuring oxygen concentration and electrochemical impedance (LEIM) inside the scribe. SEM/EDS was used to analyze the samples after exposure. The results show significant levels of corrosion protection at damaged locations at low cerium concentrations (3.7 wt % Ce3+ relative to the total coating mass) during 30 days of immersion in salt solution. However, for a given scribe geometry, the protection was found to be dependent on the electrolyte volume with larger electrolyte/exposed metal ratios leading to short protection time. A partial replacement of the Ce3+ by DMTD in the microcarriers resulted in a higher degree of passivation than when DMTD was used alone. Wet/dry cyclic exposure tests showed that cyclic conditions can increase the buildup of stable inhibitor-containing layers in the case of cerium-loaded silica microparticles. This underlines the need for more research using wet/dry exposure conditions.

Recently, there has been growing interest in multi-principal element alloys for hydrogen storage. However, most of the papers published so far report compositions based only on transition metal elements, which limit the gravimetric storage capacities due to their densities. Since Mg is a low-density element promising for hydrogen storage, the study of Mg-containing multi-principal element compositions is opportune. In the present work, we report for the first time the structural characterization and hydrogen storage properties of the A2B type MgTiNbCr0.5Mn0.5Ni0.5 alloy and its derivative Mg0.68TiNbNi0.55 alloy. These Mg-containing multi-principal element alloys form major BCC phase (W-type, Im 3 ¯ m) and major FCC hydride (MH2 with CaF2-type structure) when synthesized by mechanical alloying (MA) and reactive milling (RM), respectively. Hydrogen is desorbed from both RM samples in two steps, with some overlap, from different hydrides formed during synthesis. The microstructure of the Mg0.68TiNbNi0.55 composition is more homogeneous (less secondary phases), but both alloys present a total gravimetric capacity of around 1.6 wt% H2.

Superabsorbent polymers (SAPs) are well known for their ability to absorb and hold high water amounts accompanied by a high volume expansion. In this work we show the benefits of this underlying property of SAPs to induce underwater crack closure with subsequent barrier restoration in damaged protective coatings. For the proof of concept, three layer epoxy-polyester (EP) powder coating systems were developed and applied on carbon steel. In these systems the middle EP layer (also called functional layer) contained crosslinked acrylamide/acrylic acid copolymer SAPs in different amounts ranging from 0 to 40 wt%. The capability of the SAPs to close damages and extend barrier and corrosion protection was evaluated by electrochemical impedance spectroscopy (EIS), NaCl aqueous solution immersion test and optical microscopy. It was found that coatings loaded with a 20 wt% SAP led to the best overall corrosion protection for the studied systems. In order to proof the potential use of this extrinsic healing concept for multiple healing events wet-dry cycles on scratched systems were performed and the corrosion performance was followed by EIS. Although not yet optimal, the results show the potential of the concept for multiple healing events under wet-dry conditions.

Miscible S-SBR (solution styrene–butadiene copolymer)/BR (polybutadiene homopolymer) blends are used in multiple applications like modern passenger car tire treads. Despite their miscibility, there is a problem to predict tire performance due to dynamical heterogeneities present in the S-SBR/BR blends. On the one hand, S-SBR/BR blends have a thermorheologically complex behavior, which complicates the prediction of the temperature- and frequency-dependence of material properties. On the other hand, due to differences in the polarity of the individual components, the extender oils used in the elastomeric compounds could distribute unequally within the blends, where little is known about how oils interact with the two polymers. In this work a combination of Differential Scanning Calorimetry, Dynamic Mechanical Analysis, and Broadband Dielectric Spectroscopy (BDS) is used to clarify: (i) the thermorheological complexity of S-SBR/BR blends, (ii) the effect of the extender oil on the blend. The broad frequency operation of BDS allows for the analysis of the S-SBR and BR component dynamics and the effect of the oil on each of them within an S-SBR/BR (50/50) blend. Based on the discretization of individual component dynamics in the blend, conclusive remarks are made on the effect of the extender oil for either component in the blend. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 842–854., The authors are indebted to H&R €Olwerke Schindler GmbH (Hamburg, Germany) for their scientific, financial, and materials support of the current project as well as the permission to publish this work. M. Hernandez acknowledges the European Commission for a Marie Curie Fellowship (PIEF-GA-2013– 623379). The authors also acknowledge J. Bijleveld (TU Delft) for the DSC measurements.

In this study, the MgZrTiFe0.5Co0.5Ni0.5 high entropy alloy was processed by high-energy ball milling under both argon and hydrogen atmospheres. The hydrogen storage behavior of the samples was evaluated by combination of thermal analyses and in-situ synchrotron powder X-ray diffraction. It is shown that this alloy forms a body-centered cubic (BCC) structure when milled under argon pressure. The BCC phase is capable to absorb up to 1.2%wt. of hydrogen and during absorption it undergoes a phase transition forming a face-centered cubic (FCC) high entropy hydride. This FCC hydride can be directly synthesized by high-energy ball milling under hydrogen pressure.

This work reports on the development of a novel polymer blend with thermally triggered shape memory and self-healing properties. Blends were prepared by mixing a self-healing ionomer (Surlyn 9520) and polycyclooctene (with and without crosslinking agent) in different ratios. The regions of thermal activation were determined by thermogravimetric analysis, differential scanning calorimetry and oscillatory shear rheology. Consecutively, the shape memory and self-healing behaviour were investigated by a torsion procedure and tensile testing respectively. It was found that ionomer/crosslinked polycyclooctene blends of 70/30 wt% lead to polymers showing partial macroscopic healing and repeatable shape memory characteristics. The new polymer system shows both dual and triple shape memory behaviour and a near to 100% stiffness recovery after healing of crosscuts at standard ionomer healing conditions. Furthermore, the relation between terminal relaxation and self-healing in blends is shown. This study introduces a triple shape memory polymer with self-healing properties by a blending strategy thereby clearing the path for more durable materials based on shape memory properties.

The macroscopic interfacial healing behaviour in a series of urea-urethane networks as function of the hydrogen bonds and disulphides content is presented. The polymers were prepared with different crosslinking densities but with the same amount of dynamic covalent bonds (disulphide linkages). Tensile and fracture measurements were adopted to evaluate the degree of recovery of the mechanical properties after damage. Healing kinetics and healing efficiencies were quantitatively determined as a function of network composition, healing temperature and contact time. Finally, the recovery of mechanical properties was correlated with the viscoelastic response of the networks through rheological measurements and time-temperature superposition principle (TTS). The application of the TTS approach on both fracture healing and DMTA and subsequent mathematical descriptive model led to a better understanding of the influence of polymer architecture and that of the amount of reversible groups on the healing process.

The use of micron sized nanoporous diatom algae exoskeletons for inhibitor storage and sustained corrosion protection of coated aluminium structures upon damage is presented. In this concept the algae exoskeleton allows local inhibitor loading, limits the interaction between the cerium and the epoxy/amine coating and allows for diffusion-controlled release of the inhibitor when needed. The inhibitor release and corrosion protection by loaded exoskeletons was evaluated by UV/Vis spectrometry, a home-built optical-electrochemical setup, and Raman spectroscopy. Although this concept has been proven for a cerium-epoxy-aluminium alloy system the main underlying principle can be extrapolated to other inhibitor-coating-metal systems.

The main aim of this work is to study the respective contribution of the hard and soft blocks of a metal-ligand containing block copolymer to the self-healing behavior. To this aim, different block copolymers containing terpyridine were synthesized using reversible addition-fragmentation chain transfer (RAFT) polymerization. These block copolymers consisted of polystyrene as the hard block, n-butyl acrylate (BA) as soft block and terpyridine units as the ligand moiety placed at different locations in the soft block. These block copolymers were complexed with manganese(II) chloride to introduce transient crosslinks and, thus, self-healing behavior. Homopolymers with the hard and soft block only were also synthesized and tested. A quasi-irreversible crosslinking, i.e. by using nickel(II) nitrate, was performed in order to study the dynamics of the permanently (strongly) crosslinked network. Rheological master curves were generated enabling the determination of the terminal flow in these networks and the reversibility of the supramolecular interactions. Additionally, the macroscopic scratch healing behavior and the molecular mobility of the polymer chains in these supramolecular networks were investigated. A kinetic study of the scratch healing was performed to determine the similarities in temperature dependence for rheological relaxations and macroscopic scratch healing. In our previous work, we have explored the effect of strength of the reversible metal-ligand interaction and the effect of changing the ratio of hard to soft block. This work goes further in separating the individual contributions of the hard and soft blocks as well as the reversible interactions and to reveal their relative importance in the complex phenomenon of scratch healing.

Mixtures of XMg–Co containing different amounts of Mg (X = 2, 3 and 7) were reactive milled under hydrogen atmosphere. 2Mg–Co only formed the Mg 2 CoH 5 complex hydride, while the mixtures 3Mg–Co and 7Mg–Co formed different contents of Mg 2 CoH 5 and MgH 2 . Their structural features and hydrogen storage properties were analyzed by different techniques. In-situ synchrotron X-ray diffraction, combined with thermal analysis techniques, (differential scanning calorimetry, thermal gravimetric analysis and quadrupole mass spectrometer) was carried out to observe the behavior of the MgH 2 –Mg 2 CoH 5 mixtures during the first H-desorption. It was found that the presence of the Mg 2 CoH 5 complex hydride has a beneficial effect on the first H-desorption of the MgH 2 . Additionally, after first desorption, conventional hydrogenation under high pressure and high temperature of 3Mg–Co and 7Mg–Co samples led to the formation of the Mg 6 Co 2 H 11 complex hydride. The presence of Mg 6 Co 2 H 11 considerably impaired the desorption properties of the nanocomposites.

Different block copolymers containing terpyridine were synthesized applying the reversible addition–fragmentation chain transfer (RAFT) polymerization. The block copolymers contain polystyrene as hard block, and the soft block consists of n-butyl acrylate (BA) as well as terpyridine units as ligand. These block copolymers were further cross-linked with several metal salts in order to tune the self-healing behavior. Metallopolymers cross-linked with manganese(II) chloride featured the best self-healing behavior. Furthermore, a two-step mechanism behind the self-healing process of these metallopolymers could be attributed to each block of the copolymer and was studied extensively. In addition, rheological parameters were determined and correlated with the other results.

A new polymeric material utilizing a highly efficient as well as reversible thiol-ene click reaction is presented. For this purpose, a trithiol is reacted with a bisbenzylcyanoacetamide derivative resulting in the formation of a dynamic polymer network. The self-healing ability of this novel material is tested by scratch healing experiments. Healing is found to take place from 60 °C onward. The underlying healing mechanism is studied in detail using temperature-dependent Raman spectroscopy confirming the reversible opening of the thiol-ene adducts. Additionally, the thermal and mechanical properties are investigated by differential scanning calorimetry, thermogravimetric analysis, and rheological measurements proving the network formation as well as its reversibility during the thermal treatment.

International audience; The mean oxidation state of cationic elements in Pr2NiO4+δ was studied using XANES measurements versus temperature in air. Unexpectedly, praseodymium is solely found as Pr3+ while Pr4+ was also foreseeable. Pr3+ cation is well accommodated in the large rare-earth site with the nine-fold coordination in this K2NiF4 – T-type structure; conversely, the small size of the Pr4+ cation seems not compatible with this site. Moreover, XANES measurements show a progressive decrease of the mean oxidation state of nickel ions when the temperature increases. It is directly correlated to the decrease of the oxygen over-stoichiometry of the material evidenced by TGA measurements.

An in-situ hyphenated optical and electrochemical method for the real-time study of corrosion and corrosion inhibition processes is presented and validated for the case of AA2024-T3 exposed to two NaCl concentrations and six inhibitors. During testing, 5 μm resolution optical images of the exposed surface are obtained in parallel to electrochemical impedance measurements using a home-made 3D printed electrochemical cell. This method allowed obtaining both optical and electrochemical information of the studied surface with high time correlation. A data treatment analysis of the optical images was established thereby allowing the identification and quantification of corrosion-features related to intermetallic corrosion (e.g. trenching and meta-stable pitting) and co-operative corrosion (e.g. corrosion-rings, domes and surface-oxides) on a spatiotemporal scale, generally only observed through the use of ex-situ methods such as SEM. In addition, the study of the long-term corrosion inhibition of six inhibitors at concentrations ranging from 10−3 M to 10−6 M allowed quantifying inhibition kinetics as well as identifying different inhibitor and concentration dependent mechanisms (e.g. Cerium and DEDTC vs. Lithium) and decreasing incongruences between impedance and inhibition behaviour (e.g. DMTD). As a result, the use of quantifiable in-situ optical analysis is confirmed as a powerful tool to better interpret electrochemical signals or monitor electrochemical-dependent surface phenomena.

Single-phased La0.6Sr0.4Co1-yFeyO3-d (y = 0.2, 0.5, 0.8) nanorods exhibiting the rhombohedral perovskite-type phase were synthesized by a pore-wetting technique. We studied their chemical composition, crystal and electronic structures, morphology and hyperfine properties as a function of the Co/Fe content of the samples. Our results demonstrate that Co cations exhibit a slightly lower oxidation state than Fe ones, resulting in a higher oxygen non-stoichiometry d for Co-rich samples. In addition, the values of d determined in this work for nanostructured samples are much higher than those reported in the literature for bulk materials. This can be attributed to the high degree of defects in nanomaterials and is probably one important factor in the high electrochemical performance for the oxygen reduction reaction of nanostructured La0.6Sr0.4Co1-yFeyO3-d IT-SOFC cathodes, which have been reported in a previous work. Keywords: electrode materials; nanostructured materials; X-ray diffraction; NEXAFS; M\"ossbauer spectroscopy, Comment: 18 pages, 8 figures, accepted for publication

A self-healing sulfur vulcanized natural rubber (NR) is here reported using the common ingredients in a traditional NR formulation. The dynamic character of the di- and polysulfide bonds naturally present in covalently cross-linked rubbers was found to be responsible for the healing ability and the full recovery of mechanical properties at moderate temperatures provided the material was employed in a nonfully cured starting state. Results show that a compromise between mechanical performance and healing capability can be reached by tailoring the amount of sulfur, the cross-linking density, and the disulfide/polysulfide ratio. The healing efficiency was found to depend on the postcuring storage time, the time between damage creation and re-establishment of mechanical contact, and the actual healing time. Furthermore, a dedicated electron spin resonance (ESR) test allowed establishing the underlying healing principle based on temperature-induced free sulfur radicals. The main observations presented here can serve as the basis for the design and preparation of other self-healing polymers with long-term durability based on di-/polysulfide bridges and other reversible moieties.

Recent demands for polymers with autonomous self-healing properties are being constantly raised due to the need for high-performance and reliable materials. So far, the advances in this field are limited to the production of self-healing materials requiring a high energy input. Therefore there is an urgent need to develop self-healing polymer systems, in which healing can be easily and specifically induced by external stimuli for economical and viable applications. In the current work we demonstrate, for the first time to our knowledge, the possibility to heal local macroscopic damage by a confined temperature increase arising from the Joule effect. The damage healing is promoted by the resistance to an electrical current at the crack tip. This new concept is studied on thermo-reversible and electrically conductive poly(ester-urethane)/carbon nanotube nanocomposites derived from thermo-reversible Diels–Alder reactions between furfuryl- and maleimide-functionalized poly(e-caprolactone) (PCL)-based precursors. Electrically conductive materials are then obtained after incorporating multi-walled carbon nanotubes into the thermo-reversible networks using reactive extrusion. Under mild electrical conditions, temperature in the range of the retro-Diels–Alder reaction can be obtained near the damaged site. The obtained results reveal the potential of this new approach for healing materials locally while maintaining the overall material properties.

Mussel byssal threads are well-known due to their self-healing ability after the mechanical stress caused by waves. The proposed mechanism demonstrates the importance of reversible histidine-metal interactions as well as the block copolymer-like hierarchical architecture of the underlying protein structure. Taking these two aspects as inspiration for the design of synthetic analogs, different histidine-rich block copolymers were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. The hard domain was mimicked using polystyrene and the soft domain consists of n-butyl acrylate (BA) as well as histidine moieties as ligands. The block copolymers were crosslinked using different zinc(ii) salts and the resulting metallopolymers were investigated with respect to their self-healing abilities. The observed two-step mechanism of the self-healing process was studied in detail. Furthermore, the mechanical properties were determined by nanoindentation and were correlated with other results.

In this work, a new concept is introduced for active corrosion protection at damaged sites aiming at overcoming existing limitations of currently proposed strategies based on dispersed inhibitor-loaded nanocontainers in coatings. The underlying principle is based on the formation of low-density and/or humidity responsive interconnected paths of inhibitor in the coating, what is called inhibiting nanonetworks. Such an approach allows for (on-demand) long-term local supply of corrosion inhibitor at the damage site. For the proof-of-concept, water responsive inhibiting nanonetworks based on polyvinyl alcohol and two known efficient corrosion inhibitors for AA2024-T3 (cerium chloride and lithium carbonate) using electrospinning are developed. The inhibiting nanonetworks are obtained by subsequently embedding the electrospun fiber mats in thermoset epoxy coatings applied on AA2024-T3. The coated panels are scratched and exposed to NaCl solutions for a month while continuously monitoring the protective properties electrochemically and optically in a hyphenated setup. The effect of the corrosion inhibitor type and the partial crosslinking of the mat on release and protection are analyzed. Protection levels at relatively big damaged sites are obtained for at least a month immersion thereby proving the benefits of high inhibitor quantities continuously released in time.

A series of 18 ruthenium(II) polypyridyl complexes were synthesized and evaluated under electrochemically oxidative conditions, which generates the Ru(III) oxidation state and mimics the harsh conditions experienced during the kinetically limited regime that can occur in dye-sensitized solar cells (DSSCs) and dye-sensitized photo-electrosynthesis cells, to further develop fundamental insights into the factors governing molecular sensitizer surface stability in aqueous 0.1 M HClO4. Both desorption and oxidatively induced ligand substitution were observed on planar fluorine-doped tin oxide (FTO) electrodes, with a dependence on the E1/2 Ru(III/II) redox potential dictating the comparative ratios of the processes. Complexes such as RuP4OMe (E1/2 = 0.91 vs Ag/AgCl) displayed virtually only desorption, while complexes such as RuPbpz (E1/2 > 1.62 V vs Ag/AgCl) displayed only chemical decomposition. Comparing isomers of 4,4′- and 5,5′-disubstituted-2,2′-bipyridine ancillary ligands, a dramatic increase in the ra...

In the current paper the corrosion inhibition synergy between Ce3+ loaded NaY-zeolite (NaY-Ce) and 2-Mercaptobenzothiazole (MBT) loaded Zn-Al layered double hydroxide (LDH-MBT) containers is presented. Solutions and water-borne epoxy coatings containing different ratios of the two loaded carriers were prepared and their protection of AA2024-T3 and damaged coatings characterized using global and local electrochemical techniques and other complementary tools. The coatings containing container-combinations showed exceptional corrosion protection over a broad range of NaY-Ce:LDH-MBT weight ratios, with 90:10 being the optimal. The current work landmarks the need for synergetic inhibiting studies devoted to carrier-inhibitor systems in coatings.

Background TolT was originally described as a Trypanosoma cruzi molecule that accumulated on the trypomastigote flagellum bearing similarity to bacterial TolA colicins receptors. Preliminary biochemical studies indicated that TolT resolved in SDS-PAGE as ~3–5 different bands with sizes between 34 and 45 kDa, and that this heterogeneity could be ascribed to differences in polypeptide glycosylation. However, the recurrent identification of TolT-deduced peptides, and variations thereof, in trypomastigote proteomic surveys suggested an intrinsic TolT complexity, and prompted us to undertake a thorough reassessment of this antigen. Methods/Principle findings Genome mining exercises showed that TolT constitutes a larger-than-expected family of genes, with at least 12 polymorphic members in the T. cruzi CL Brener reference strain and homologs in different trypanosomes. According to structural features, TolT deduced proteins could be split into three robust groups, termed TolT-A, TolT-B, and TolT-C, all of them showing marginal sequence similarity to bacterial TolA proteins and canonical signatures of surface localization/membrane association, most of which were herein experimentally validated. Further biochemical and microscopy-based characterizations indicated that this grouping may have a functional correlate, as TolT-A, TolT-B and TolT-C molecules showed differences in their expression profile, sub-cellular distribution, post-translational modification(s) and antigenic structure. We finally used a recently developed fluorescence magnetic beads immunoassay to validate a recombinant protein spanning the central and mature region of a TolT-B deduced molecule for Chagas disease serodiagnosis. Conclusion/Significance This study unveiled an unexpected genetic and biochemical complexity within the TolT family, which could be exploited for the development of novel T. cruzi biomarkers with diagnostic/therapeutic applications., Author summary Chagas disease, caused by the protozoan Trypanosoma cruzi, is a lifelong and debilitating neglected illness of major significance in Latin America, for which no vaccine or adequate drugs are yet available. Identification of novel biomarkers able to transcend the current limits of diagnostic and/or therapeutic assessment methods hence surfaces as a main priority in Chagas disease applied research. In this framework, we herein undertook a thorough biochemical and antigenic characterization of T. cruzi TolT surface antigens. Our results unveil an unexpected complexity within this family, with at least 12 polymorphic TolT genes in the T. cruzi CL Brener reference strain genome. According to structural features, TolT deduced molecules could be split into three robust groups that show differences in their structural features, expression profile, sub-cellular distribution, post-translational modification(s) and antigenic structure. Overall, we show that TolT molecules are conspicuously expressed by both major mammal-dwelling stages of the parasite, and that they are differentially recognized by the immune system in Chagasic patients and in T. cruzi-infected mammals. Our findings are discussed in terms of the evolution and possible structural/functional roles of TolT molecules, as well as in terms of their applicability in Chagas disease serodiagnosis.

In this work we report the effect of the hard block dianhydride structure on the overall properties of partially biobased semiaromatic polyimides. For the study, four polyimides were synthesized using aliphatic fatty dimer diamine (DD1) as the soft block and four different commercially available aromatic dianhydrides as the hard block: 4,4¿-(4,4¿-isopropylidenediphenoxy) bis(phthalic anhydride) (BPADA), 4,4¿-oxidiphthalic anhydride (ODPA), 4,4¿-(Hexafluoroisopropylidene) diphthalic anhydride (6FDA), and 3,3¿,4,4¿-biphenyltetracarboxylic dianhydride (BPDA). The polymers synthesized were fully organo-soluble thermoplastic branched polyimides with glass transition temperatures close to room temperature. The detailed analysis took into account several aspects of the dianhydrides structure (planarity, rigidity, bridging group between the phtalimides, and electronic properties) and related them to the results obtained by differential scanning calorimetry, rheology, fluorescence and broadband dielectric spectroscopy. Moreover, the effects of physical parameters (crystallization and electronic interactions) on the relaxation behavior are discussed. Despite the presence of the bulky branched soft block given by the dimer diamine, all polyimides showed intermolecular charge transfer complexes, whose extent depends on the electronic properties of the dianhydride hard block. Furthermore, the results showed that polyimides containing flexible and bulky hard blocks turned out fully amorphous while the more rigid dianhydride (BPDA) led to a nanophase separated morphology with low degree of crystallinity resulting in constrained segmental relaxation with high effect on its mechanical response with the annealing time. This work represents the first detailed report on the development and characterization of polyimides based on a biobased fatty dimer diamine. The results highlight the potential of polymer property design by controlled engineering of the aromatic dianhydride blocks., We thank Professor Sybrand van der Zwaag for his continued interest in the work and valuable comments on the manuscript during its construction. The authors acknowledge the financial support from the Dutch IOP program on self-healing materials under Grant No. IOP-SHM-012036. We acknowledge our industrial partner Croda Nederland BV, especially the sustained support and valuable discussions with Dr. Angela Smits (Croda). Many thanks to Dr. Brian Richard Pauw (Bundesanstalt für Materialforschung und−prüfung, Berlin) for performing the SAXS measurements

A comparative study is performed on the monitoring of delamination healing in CFRP-ionomer sandwich composites by non-destructive techniques and destructive compression testing. Artificial delaminations of various areal dimensions and nature were introduced during production of the composites. The extent of the delamination and the healing thereof was monitored in both air and water-coupled ultrasonic C-scan experiments as well as by the frequency shift of the local defect resonance (LDR). It is shown that the LDR approach can be used to detect the early stage healing of the delaminations while ultrasonic C-scanning techniques are very effective to determine the extent of healing in the final stages of the repair process. A quasi-linear relation was observed between the delaminated area measured with ultrasonic C-scan and the compressive failure strength in destructive testing. This correlation shows the beneficial effect on the compression strength of the delaminated area reduction by on-demand healing.

Two sulfonated aramids, poly(2,2′-disulfonylbenzidine terephthalamide) (PBDT) and poly(2,2′-disulfonylbenzidine isophthalamide) (PBDI), were synthesized with the aim to explore their unique morphology for proton exchange membrane applications. Due to the different polymer structures, PBDT forms a nematic liquid crystal, whereas PBDI is isotropic. Both polymers show excellent thermal stabilities ( T d 5 % >400 °C), high storage moduli (E′=3–15 GPa) and crosslinked films are flexible and easy to handle. Pulsed-field-gradient NMR diffusometry reveals that the in-plane water diffusion in the nematic PBDT membrane is as high as 3.3×10−10 m2/s, whereas the diffusion in amorphous PBDI is only 2.5×10−10 m2/s. Whereas neat and crosslinked PBDI shows isotropic diffusion, neat PBDT shows a high diffusion anisotropy (D∥/D⊥=3.0), which increases as a function of crosslink density (D∥/D⊥=4.6 at 80% crosslinking). This diffusion anisotropy is substantially higher than that typically observed for low molecular weight liquid crystals and for oriented polymeric conductors such as Nafion® (D∥/D⊥~2.0). The nematic order in the PBDT membrane also promotes directed ionic conductivity, i.e. Na+ conductivity in PBDT is 2.24×10−2 S/cm and 1.67×10−2 S/cm for PBDI, respectively. We propose that the rigid-rod PBDT chains form nano-scale hydrophilic channels, which act as pathways for transporting water molecules and ions.

Controlling the strain in two-dimensional (2D) materials is an interesting avenue to tailor the mechanical properties of nanoelectromechanical systems. Here, we demonstrate a technique to fabricate ultrathin tantalum oxide nanomechanical resonators with large stress by the laser oxidation of nano-drumhead resonators composed of tantalum diselenide (TaSe2), a layered 2D material belonging to the metal dichalcogenides. Before the study of their mechanical properties with a laser interferometer, we verified the oxidation and crystallinity of the freely suspended tantalum oxide using high-resolution electron microscopy. We demonstrate that the stress of tantalum oxide resonators increases by 140 MPa (with respect to pristine TaSe2 resonators), which causes an enhancement in the quality factor (14 times larger) and resonance frequency (9 times larger) of these resonators.

The aim of this work is to contribute to the understanding of the relationship between the timescales of molecular processes in ionomers and that of macroscale autonomous healing. For this purpose, poly(butyl acrylate-co-acrylic acid) model ionomers with varying fractions of cobalt counter ions were used. Three temperature dependent timescales were quantified and linked: (i) the terminal relaxation time (td) as determined by creep relaxation experiments; (ii) the supramolecular relaxation timescale (t) as determined by frequency sweeps in oscillatory shear rheology; and (iii) the macroscopic healing timescale (theal) as obtained by quantifying the time for full interfacial strength recovery for two ionomer surfaces brought in contact. Using the temperature dependent values of td, t, and theal, the activation energies of the ionic cluster formation, the flow of the polymer backbone, and the interfacial recovery respectively, were calculated. It was found that the kinetics of healing closely follows the timescales of network and cluster formation.

Pulsed laser deposition (PLD) was used to grow ZnO thin films on corning glass and silicon substrates at different oxygen pressures (1 y 10 mTorr). The structural analysis of the films was performed by X-ray diffraction and pulsed laser photoacoustic (PLPA) techniques. Both methods were employed to identify the minority zinc blende phase in the films. The relative difference between the structural changes detected in the films with the temperature increases was statistically analyzed. It was found that regardless of the substrate and the oxygen pressure used for the growth, the films exhibit a phase transition at 310 °C, which corresponds to the transformation of zinc blende structure to hexagonal wurtzite. The results demonstrate that the zinc blende phase in the films is present not only on cubic substrates but also on glass, and confirm that PLPA technique is a very sensitive method for the detection of minority phase changes.

The utilization of dynamic covalent and noncovalent bonds in polymeric materials offers the possibility to regenerate mechanical damage, inflicted on the material, and is therefore of great interest in the field of self-healing materials. For the design of a new class of self-healing materials, methacrylate containing copolymers with acylhydrazones as reversible covalent crosslinkers are utilized. The self-healing polymer networks are obtained by a bulk polymerization of an acylhydrazone crosslinker and commercially available methacrylates as comonomers to fine-tune the Tg of the systems. The influence of the amount of acylhydrazone crosslinker and the self-healing behavior of the polymers is studied in detail. Furthermore, the basic healing mechanism and the corresponding mechanical properties are analyzed.

Ni promoted tungsten carbides have been shown to be an effective catalyst for cellulose conversion reaction. With the use of both in situ and ex situ techniques an investigation into the physical and chemical aspects of the Ni-promoted tungsten carbide catalyst supported on activated carbon either in pure form or functionalized with sulfuric acid was conducted. In situ XRD analysis performed during the carburization process showed that non-promoted samples formed a mixture of nanosized W2C, WC1−x and WC carbide phases. In the case of Ni promoted catalysts, in situ XRD, XANES, XPS and TEM analysis revealed that Ni aids in lowering the carburization temperature by 50 °C but also assisted in the deposition of polymeric carbon onto the catalyst surface which reduced cellulose conversion. However, the results indicate beneficial effects caused by the high carbon coverage by stopping the W2C to WC carbide phase transition. Thus, carburization of Ni promoted samples produced only W2C phase, which is stable up to 800 °C. The functionalization of activated-carbon with –SO3H not only increases the hydrolysis of cellulose but also lead to a greater dispersion of Ni over the catalyst. The resulting improvement in the interaction between Ni/W/C increases the cellulose transformation in a one-pot synthesis towards the production of ethylene glycol.

Certain metallopolymers possess the ability to close scratches by a simple thermal treatment. The present study comprehensively explores the structure–property relationship of these materials by variation of the corresponding metal salts. The scratch-healing properties are studied in detail and correlated to the rheological behavior. Rheological measurements are utilized to determine the supramolecular bond life time (τb). A crossover of G′ and G′′ is found for the scratch healing metallopolymers, whereas this is absent in materials displaying no healing under the investigated conditions. Thus, this study provides a first step for the fundamental understanding of the dynamic behavior of metallopolymers and the impact on the self-healing properties. Furthermore, the effect of the chosen cation and anion on the self-healing behavior is illustrated and studied in detail.

In this work, we correlate network dynamics, supramolecular reversibility and the macroscopic surface scratch healing behavior for a series of elastomeric ionomers based on an amorphous backbone with varying fractions of carboxylate pendant groups completely neutralized by Na(+), Zn(2+) or Co(2+) as the counter ions. Our results based on temperature dependent dynamic rheology with simultaneous FTIR analysis clearly indicate that the effective supramolecular bond lifetime (τ(b)) is an important parameter to ascertain the ideal range of viscoelasticity for good macroscopic healing. The reversible coordination increased with higher valence metal ions and ionic content. Both rheological and spectroscopic analyses show a decrease in supramolecular assembly with temperature. The temperature dependent τ(b) was used to calculate the activation energy (Ea) of dissociation for the ionic clusters. According to self-healing experiments based on macroscale surface scratching, a supramolecular bond lifetime between 10 and 100 s results in samples with complete surface scratch healing and good mechanical robustness.

Magnesium complex hydrides are attractive for hydrogen storage applications, mainly due to their high volumetric capacities and to their relatively low cost. In this work, nanocrystalline Mg2CoH5 was synthesized with very high yields (97%) by reactive milling cobalt and magnesium under relatively mild processing conditions (30 bar of H2 pressure and 12 h of milling). The behavior of the milled Mg2CoH5 during heating was studied by a combination of several techniques including DSC, QMS, TGA and in-situ synchrotron XRD. It is shown for the first time that two different mechanisms of hydrogen desorption take place. At low temperatures (up to 325°C), some hydrogen is released by a diffusional mechanism with no change in the crystalline structure of the high temperature γ-Mg2CoH5 phase. At higher temperatures, above 325°C, the γ-Mg2CoH5 phase becomes unstable and the complex hydride decomposes into Mg, Co and H2. This is the first work to report the diffusional hydrogen desorption mechanism for the Mg2CoH5 or any other complex hydride. Furthermore, a complete description of the allotropic β-Mg2CoH5 to γ-Mg2CoH5 phase transition is provided. Fil: Zepon, G.. Universidade Federal do São Carlos; Brasil Fil: Leiva, D. R.. Universidade Federal do São Carlos; Brasil Fil: Kaufman, M. J.. Colorado School of Mines; Estados Unidos Fil: Figueroa, Santiago Jose Alejandro. Centro Nacional de Pesquisa em Energia e Materiais Rua Giuseppe Máximo Scolfaro; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Floriano, R.. Universidade Estadual de Campinas; Brasil Fil: Lamas, Diego Germán. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina Fil: Asselli, A. A. C.. Universidade Federal do São Carlos; Brasil Fil: Botta, W. J.. Universidade Federal do São Carlos; Brasil

Compartmented fibres containing liquid healing agents have been proposed as a new method to provide local healing in fibre reinforced polymer composites. The compartmented fibres do not contribute to the mechanical properties of the composite but only serve to locally distribute the sources of healing agent and to overcome the intrinsic problems associated with hollow fibres and spherical capsules as containers for the healing agent. In this work the intended multiple local release and healing functionality in a thermoplastic matrix is successfully demonstrated using X-ray micro-tomography and a modified three-point bending test. The results here presented further support the potential of this new concept for the development of self-healing composites.