Artículos de revistas: "Interface hydrogel/substrat"

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Lin, Yue-Xian, Shu-Han Li y Wei-Chen Huang. "Fabrication of Soft Tissue Scaffold-Mimicked Microelectrode Arrays Using Enzyme-Mediated Transfer Printing". Micromachines 12, n.º 9 (31 de agosto de 2021): 1057. http://dx.doi.org/10.3390/mi12091057.

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Hydrogels are the ideal materials in the development of implanted bioactive neural interfaces because of the nerve tissue-mimicked physical and biological properties that can enhance neural interfacing compatibility. However, the integration of hydrogels and rigid/dehydrated electronic microstructure is challenging due to the non-reliable interfacial bonding, whereas hydrogels are not compatible with most conditions required for the micromachined fabrication process. Herein, we propose a new enzyme-mediated transfer printing process to design an adhesive biological hydrogel neural interface. The donor substrate was fabricated via photo-crosslinking of gelatin methacryloyl (GelMA) containing various conductive nanoparticles (NPs), including Ag nanowires (NWs), Pt NWs, and PEDOT:PSS, to form a stretchable conductive bioelectrode, called NP-doped GelMA. On the other hand, a receiver substrate composed of microbial transglutaminase-incorporated gelatin (mTG-Gln) enabled simultaneous temporally controlled gelation and covalent bond-enhanced adhesion to achieve one-step transfer printing of the prefabricated NP-doped GelMA features. The integrated hydrogel microelectrode arrays (MEA) were adhesive, and mechanically/structurally bio-compliant with stable conductivity. The devices were structurally stable in moisture to support the growth of neuronal cells. Despite that the introduction of AgNW and PEDOT:PSS NPs in the hydrogels needed further study to avoid cell toxicity, the PtNW-doped GelMA exhibited a comparable live cell density. This Gln-based MEA is expected to be the next-generation bioactive neural interface.

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Liu, Junjie, Nan Hu, Yao Xie, Peng Wang, Jingxiang Chen y Qianhua Kan. "Polyacrylic Acid Hydrogel Coating for Underwater Adhesion: Preparation and Characterization". Gels 9, n.º 8 (29 de julio de 2023): 616. http://dx.doi.org/10.3390/gels9080616.

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Underwater adhesion involves bonding substrates in aqueous environments or wet surfaces, with applications in wound dressing, underwater repairs, and underwater soft robotics. In this study, we investigate the underwater adhesion properties of a polyacrylic acid hydrogel coated substrate. The underwater adhesion is facilitated through hydrogen bonds formed at the interface. Our experimental results, obtained through probe-pull tests, demonstrate that the underwater adhesion is rapid and remains unaffected by contact pressure and pH levels ranging from 2.5 to 7.0. However, it shows a slight increase with a larger adhesion area. Additionally, we simulate the debonding process and observe that the high-stress region originates from the outermost bonding region and propagates towards the center, spanning the thickness of the target substrate. Furthermore, we showcase the potential of using the underwater adhesive hydrogel coating to achieve in-situ underwater bonding between a flexible electronic demonstration device and a hydrogel contact lens. This work highlights the advantages of employing hydrogel coatings in underwater adhesion applications and serves as inspiration for the advancement of underwater adhesive hydrogel coatings capable of interacting with a wide range of substrates through diverse chemical and physical interactions at the interface.

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Yang, Yueh-Hsun Kevin, Courtney R. Ogando y Gilda A. Barabino. "In Vitro Evaluation of the Influence of Substrate Mechanics on Matrix-Assisted Human Chondrocyte Transplantation". Journal of Functional Biomaterials 11, n.º 1 (18 de enero de 2020): 5. http://dx.doi.org/10.3390/jfb11010005.

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Matrix-assisted chondrocyte transplantation (MACT) is of great interest for the treatment of patients with cartilage lesions. However, the roles of the matrix properties in modulating cartilage tissue integration during MACT recovery have not been fully understood. The objective of this study was to uncover the effects of substrate mechanics on the integration of implanted chondrocyte-laden hydrogels with native cartilage tissues. To this end, agarose hydrogels with Young’s moduli ranging from 0.49 kPa (0.5%, w/v) to 23.08 kPa (10%) were prepared and incorporated into an in vitro human cartilage explant model. The hydrogel-cartilage composites were cultivated for up to 12 weeks and harvested for evaluation via scanning electron microscopy, histology, and a push-through test. Our results demonstrated that integration strength at the hydrogel-cartilage interface in the 1.0% (0.93 kPa) and 2.5% (3.30 kPa) agarose groups significantly increased over time, whereas hydrogels with higher stiffness (>8.78 kPa) led to poor integration with articular cartilage. Extensive sprouting of extracellular matrix in the interfacial regions was only observed in the 0.5% to 2.5% agarose groups. Collectively, our findings suggest that while neocartilage development and its integration with native cartilage are modulated by substrate elasticity, an optimal Young’s modulus (3.30 kPa) possessed by agarose hydrogels is identified such that superior quality of tissue integration is achieved without compromising tissue properties of implanted constructs.

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Pickrell, D. J., W. Zhu, A. R. Badzian, R. E. Newnham y R. Messier. "Near-interface characterization of diamond films on silica and silicon". Journal of Materials Research 6, n.º 6 (junio de 1991): 1264–77. http://dx.doi.org/10.1557/jmr.1991.1264.

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The near-interface structure of diamond films grown from a methane and hydrogen gas mixture by microwave plasma enhanced chemical vapor deposition has been studied. Freestanding diamond films grown on both silica and silicon at two different methane concentrations were analyzed by scanning and transmission electron microscopies, electron diffraction, Raman spectroscopy, and secondary ion mass spectroscopy. It was found that the substrate chemistry greatly influenced the nature of the carbon initially deposited on the substrate surface. Diamond formed large flat contact areas on silicon, whereas on silica a particulate type of intermediate layer formed first because of the chemical reactions occurring on and/or with the surface. It was found that the phase content of the films was greatly affected by the methane concentration in hydrogen. At the low (1.0% or less) methane concentrations in hydrogen, phase pure diamond formed; while at the high (5.0%) methane concentration in hydrogen, graphite and disordered carbon were codeposited along with diamond during the early growth stages. Silicon carbide was detected at the diamond interfaces which appeared in discrete areas on silica as opposed to a rather continuous layer as is believed to form on silicon.

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Hens, Philip, Julian Müller, Erdmann Spiecker y Peter J. Wellmann. "Defect Structures at the Silicon/3C-SiC Interface". Materials Science Forum 717-720 (mayo de 2012): 423–26. http://dx.doi.org/10.4028/www.scientific.net/msf.717-720.423.

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In all heteroepitaxial systems the interface between substrate and layer is a crucial point. In this work SEM and TEM studies on the interface between silicon substrate and cubic silicon carbide (3C-SiC) layers obtained by chemical vapor deposition (CVD) are presented. A clear connection between process parameters, like the design of substrate cleaning, and the heating ramp, and resulting defect structures at the substrate-layer interface could be found. Whereas the process step of etching in hot hydrogen for oxide removal is crucial for avoiding the generation of closed voids of type 2, the design of the temperature ramp up to growth temperature during carbonization influences the interface roughness. Here a fast ramp helps to obtain a flat interface.

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Bordbar-Khiabani, Aydin, Ilijana Kovrlija, Janis Locs, Dagnija Loca y Michael Gasik. "Octacalcium Phosphate-Laden Hydrogels on 3D-Printed Titanium Biomaterials Improve Corrosion Resistance in Simulated Biological Media". International Journal of Molecular Sciences 24, n.º 17 (24 de agosto de 2023): 13135. http://dx.doi.org/10.3390/ijms241713135.

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The inflammatory-associated corrosion of metallic dental and orthopedic implants causes significant complications, which may result in the implant’s failure. The corrosion resistance can be improved with coatings and surface treatments, but at the same time, it might affect the ability of metallic implants to undergo proper osteointegration. In this work, alginate hydrogels with and without octacalcium phosphate (OCP) were made on 3D-printed (patterned) titanium alloys (Ti Group 2 and Ti-Al-V Group 23) to enhance their anticorrosion properties in simulated normal, inflammatory, and severe inflammatory conditions in vitro. Alginate (Alg) and OCP-laden alginate (Alg/OCP) hydrogels were manufactured on the surface of 3D-printed Ti substrates and were characterized with wettability analysis, XRD, and FTIR. The electrochemical characterization of the samples was carried out with open circuit potential, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS). It was observed that the hydrophilicity of Alg/OCP coatings was higher than that of pure Alg and that OCP phase crystallinity was increased when samples were subjected to simulated biological media. The corrosion resistance of uncoated and coated samples was lower in inflammatory and severe inflammatory environments vs. normal media, but the hydrogel coatings on 3D-printed Ti layers moved the corrosion potential towards more nobler values, reducing the corrosion current density in all simulated solutions. These measurements revealed that OCP particles in the Alg hydrogel matrix noticeably increased the electrical charge transfer resistance at the substrate and coating interface more than with Alg hydrogel alone.

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Arendse, Christopher J., Theophillus F. G. Muller, Franscious R. Cummings y Clive J. Oliphant. "Oxidation Reduction in Nanocrystalline Silicon Grown by Hydrogen-Profiling Technique". Journal of Nano Research 41 (mayo de 2016): 9–17. http://dx.doi.org/10.4028/www.scientific.net/jnanor.41.9.

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The deposition of a compact amorphous silicon/nano-crystalline silicon material is demonstrated by hot-wire chemical vapour deposition using a sequential hydrogen profiling technique at low hydrogen dilutions. Nano-crystallite nucleation occurs at the substrate interface that develops into a uniform, porous crystalline structure as the growth progresses. A further reduction in the H-dilution results in the onset of a dense amorphous silicon layer. The average crystalline volume fraction and nano-crystallite size in the sample bulk amounts to 30% and 6 nm, respectively, as probed by Raman spectroscopy using the 647 nm excitation. The change in hydrogen dilution is accompanied by a graded hydrogen concentration depth-profile, where the hydrogen concentration decreases as the growth progresses. The level of post-deposition oxidation is considerably reduced, as inferred from infrared spectroscopy. The presence of oxygen is mainly confined to the substrate interface as a result of thermal oxidation during thin film growth.

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Zhao, Zhitong, Weiwei Gao y Hao Bai. "A mineral layer as an effective binder to achieve strong bonding between a hydrogel and a solid titanium substrate". Journal of Materials Chemistry B 6, n.º 23 (2018): 3859–64. http://dx.doi.org/10.1039/c8tb01042k.

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9

Tamura, Motonori. "Hydrogen Permeation of Multi-Layered-Coatings". Advanced Materials Research 1152 (abril de 2019): 9–18. http://dx.doi.org/10.4028/www.scientific.net/amr.1152.9.

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Using a substrate of AISI 316L austenitic stainless steel, which is used for components in high-pressure hydrogen systems, the hydrogen barrier properties of samples with single-layer coatings of TiC, TiN, and TiAlN as well as a multi-layered coating of TiAlN and TiMoN were evaluated. The ion plating method was used, and coating thicknesses of 2.0–2.6 μm were obtained. Hydrogen permeation tests were carried out under a differential hydrogen pressure of 400 kPa and at a temperature between 573 and 773 K, and the quantities of hydrogen that permeated the samples were measured. This study aimed at elucidating the relationship between the microstructures of the coatings and the hydrogen permeation properties. Coatings of TiC, TiN, TiAlN, and TiAlN/TiMoN facilitated reductions of the hydrogen permeabilities to 1/100 or less of that of the uncoated substrate. The samples coated with TiN and TiC that developed columnar crystals vertical to the substrate exhibited higher hydrogen permeabilities. The experiment confirmed that the coatings composed of fine crystal grains were highly effective as hydrogen barriers, and that this barrier property became even more efficient if multiple layers of the coatings were applied. The crystal grain boundaries of the coating and interfaces of each film in a multi-layered coating may serve as hydrogen trapping sites. We speculate that fine crystal structures with multiple crystal grain boundaries and multi-layered coating interfaces will contribute to the development of hydrogen barriers.

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Yamauchi, Akira, Yuji Yamauchi, Yuko Hirohata, Tomoaki Hino y Kazuya Kurokawa. "TDS Measurement of Hydrogen Released from Stainless Steel Oxidized in H₂O-Containing Atmospheres". Materials Science Forum 522-523 (agosto de 2006): 163–70. http://dx.doi.org/10.4028/www.scientific.net/msf.522-523.163.

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Hydrogen dissolved in the Cr2O3 scale formed on the stainless steel in the H2O-containing atmospheres is observed by TDS (thermal desorption spectroscopy) measurements. The amount of dissolved hydrogen in the Cr2O3 scale reaches a maximum about 0.32 mol% when the H2O concentration in the gas reaches 20%. It was found from GDS (glow discharge spectroscopy) measurements that hydrogen may exist at the oxide scale / substrate interface or in Cr2O3 scale bounded that interface. However, results from the Vickers hardness and the observation of scale morphology by SEM (scanning electron microscopy), hydrogen dissolved in the Cr2O3 scale would have little effect on a decrease in the mechanical property of the Cr2O3 scale. Therefore, hydrogen dissolved in the Cr2O3 scale may not be main factor of the deterioration of the Cr2O3 scale.

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Shu, Min-Fong y Yi-Hsiu Tseng. "Copper Oxidation Effect in the EMC/Cu Interfacial Adhesion Improvement for a Novel Copper Interconnection Substrate Application". International Symposium on Microelectronics 2018, n.º 1 (1 de octubre de 2018): 000161–66. http://dx.doi.org/10.4071/2380-4505-2018.1.000161.

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Abstract Copper oxidation structure, cupric oxide (CuO) and cuprous oxide (Cu2O), under Ar/H2 plasma reaction mechanism for the EMC/Cu interface adhesion improvement was studied in this work. This work is utilized TGA to figure out Cu oxidized state and sample preparation, and using plasma treatment Cu oxidation layer to evaluate the EMC/Cu interface adhesion strength by shear testing method. Results show a plasma reduction on Cu oxidation layer provide a better interface adhesion, and the layer structure has a significant composition change, Cu/Cu2O/CuO/EMC → Cu/Cu2O/CuO/Cu2O/EMC. These layer structures were identified by high-resolution TEM mapping with EELS spectrum fitting, it was also verified for CuO reduction to form Cu2O, following the Cu2O hydration would provide much hydrogen-bonding in the EMC/Cu interface. This kind of chain reaction mechanism including CuO reduction and Cu2O hydration was described by 2CuO + H2 → Cu2O +H2O → 2CuOH (hydration molecular). The reaction mechanism of the EMC/Cu bonding has been investigated and verified in this experimental study and our conclusion is that hydrogen bonding on the Cu oxidation layer surface can strengthen the EMC/Cu interface adhesion.

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Jana, Achintya, Puneet Mishra y Neeladri Das. "Polymorphic self-assembly of pyrazine-based tectons at the solution–solid interface". Beilstein Journal of Nanotechnology 10 (18 de febrero de 2019): 494–99. http://dx.doi.org/10.3762/bjnano.10.50.

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Exploring the surface self-assembly of small molecules that act as building blocks (tectons) for complex supramolecular structures is crucial for realizing surface-supported functional molecular devices. Here, we report on the synthesis and surface self-assembly of a new pyrazine-derived molecule with pyridine pendants. Ambient scanning tunneling microscopy investigation at the solution–solid interface reveals polymorphic self-assembly of these molecules on a HOPG substrate. Two different molecular packing structures with equal distribution are observed. Detailed analysis of the STM images emphasizes the crucial role of weak intermolecular hydrogen bonding, and molecule–substrate interactions in the formation of the observed polymorphs. Such weak hydrogen bonding interactions are highly desirable for the formation of modular supramolecular architectures since they can provide sufficiently robust molecular structures and also facilitate error correction.

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Zhang, Haojie, Juliana Martins de Souza e Silva, Cristine Santos de Oliveira, Xubin Lu, Stefan L. Schweizer, A. Wouter Maijenburg, Michael Bron y Ralf B. Wehrspohn. "Optimization of Chemical Vapor Deposition Process for Carbon Nanotubes Growth on Stainless Steel: Towards Efficient Hydrogen Evolution Reaction". MRS Advances 5, n.º 8-9 (2020): 363–68. http://dx.doi.org/10.1557/adv.2020.4.

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ABSTRACTWe report a novel strategy to render stainless steel (SS) a more versatile material that is suitable to be used as the substrate for preparing electrodes for efficient hydrogen evolution by interface engineering. Our strategy involves the growth of carbon nanotubes (CNTs) by atmospheric pressure chemical vapor deposition (APCVD) as the interface material on the surface of SS. We optimized the procedure to prepare CNTs/SS and demonstrate a higher activity of the CNTs/SS prepared at 700 °C for the hydrogen evolution reaction (HER) when compared to samples prepared at other temperatures. This can be attributed to the higher number of defects and the higher content of pyrrolic N obtained at this temperature. Our strategy offers a new approach to employ SS as a substrate for the preparation of highly efficient electrodes and has the potential to be widely used in electrochemistry.

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Kim, J. Y., J. S. Hardy y K. S. Weil. "High-temperature tolerance of the silver-copper oxide braze in reducing and oxidizing atmospheres". Journal of Materials Research 21, n.º 6 (1 de junio de 2006): 1434–42. http://dx.doi.org/10.1557/jmr.2006.0178.

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The silver-copper oxide–based reactive air brazing technique was developed as a method of joining complex-shaped ceramic parts. To investigate the viability of this approach for high-temperature application, a series of air-brazed alumina joints were independently exposed to either oxidizing or reducing atmosphere at 800 °C for 100 h. Those samples that were thermally aged in air maintained good joint strength, similar to that of the original as-brazed samples. Microstructural analysis revealed no significant change in joint microstructure after long-term oxidation at elevated temperature, indicating excellent stability of the Ag–CuO-based filler metal in this environment. On the other hand, exposure of the air-brazed alumina joints to hydrogen under the same aging conditions resulted in a measurable decrease in joint strength. Scanning electron microscope analysis conducted on the fracture surfaces of the broken hydrogen-exposed specimens indicated that the source of joint failure was debonding along the interface between the filler metal and alumina substrate. This was due in large part to internal reduction of CuO precipitates within the filler metal to copper and accompanied by the simultaneous formation of porosity at these sites, both within the bulk of the joint as well as along the filler metal/substrate interfaces. Pore formation was noticeably present in filler metals prepared with a high concentration of copper oxide.

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Zeng, Xiang Bo, Jin Yan Li, Xiao Bing Xie, Ping Yang, Hao Li, Hai Bo Xiao, Xiao Dong Zhang y Qi Ming Wang. "Improvement of n/i Interface Layer Properties in Microcrystalline Silicon Solar Cell". Key Engineering Materials 537 (enero de 2013): 193–96. http://dx.doi.org/10.4028/www.scientific.net/kem.537.193.

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Properties of n-i interface are critical for hydrogenated microcrystalline silicon (μc-Si:H )substrate-type (n–i–p) solar cell as it affects carrier collection, which is visible in the red response . Here, we report a remarkable improvement in visible-infrared responses upon hydrogen plasma treatment （HPT）of n/i interface. We demonstrate that hydrogen plasma treatment in the initial stage of a μc-Si:H i layer growth affects the red response of μc-Si:H solar cell. At the optimal deposition condition, 18% higher short-circuit current density was obtained than its count part without using HPT

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Hirakata, Hiroyuki, Takeshi Yamada, Yoshiki Nobuhara, Akio Yonezu y Kohji Minoshima. "Hydrogen effect on fracture toughness of thin film/substrate interfaces". Engineering Fracture Mechanics 77, n.º 5 (marzo de 2010): 803–18. http://dx.doi.org/10.1016/j.engfracmech.2009.11.011.

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De Obaldia, Elida, Pablo Tirado, Jesús Alcantar, Jorge Montes y Orlando Auciello. "Photoluminescence in Raman Scattering: Effects of HfO2 Template Layer on Ultrananocrystalline Diamond (UNCD) Films Grown on Stainless Steel Substrates". KnE Engineering 3, n.º 1 (11 de febrero de 2018): 263. http://dx.doi.org/10.18502/keg.v3i1.1441.

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The growth of polycrystalline diamond films can play an important role in industry if they can be grown on industrially used materials like aluminum (Al) or stainless steel (SS). A critical issue related to the growth of ultrananocrystalline diamond (UNCD) thin films on metals like SS, in a Hydrogen rich environment like the one present during growth of UNCD films, is the diffusion of Hydrogen (H) into the SS substrate, as it has been observed in prior research, which results in hydride formation in the SS that induce brittleness in the SS substrate. Several interface layers have been proposed described to avoid the H diffusion into the SS. However, HfO2 has not been explored. The work reported here was focused on investigating the growth of UNCD films on commercially available SS substrates by using an interface layer of HfO2, which was found to be a good diffusion barrier for H to inhibit penetration into the SS substrate. The samples where characterized with SEM and Raman spectroscopy. A photoluminescence (PL) effect, observed in the Raman scattering analysis, is present in all the samples. The PL effect may be due to the interaction of the UNCD / HfO2 interface. and the SS substrate rather than UNCD film alone. The novel result from the experiments described here, is the fact that it is possible to grow UNCD films on unseeded HfO2 layers on SS substrates.Keywords: Poly-crystalline diamond, photoluminescence, UNCD, Stainless Steel, Hafnium Dioxide

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Yurakov, Yury A., Yaroslav A. Peshkov, Evelina P. Domashevskaya, Vladimir A. Terekhov, Konstantin A. Barkov, Anatoly N. Lukin y Alexander V. Sitnikov. "A study of multilayer nanostructures [(Co45Fe45Zr10)35(Al2O3)65/a-Si:H]100 and [(Co45Fe45Zr10)35(Al2O3)65/a-Si]120 by means of XRD, XRR, IR spectroscopy, and USXES". European Physical Journal Applied Physics 87, n.º 2 (agosto de 2019): 21301. http://dx.doi.org/10.1051/epjap/2019190131.

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Interatomic interactions and superstructures of multilayer nanostructures (MLNS) consisting of ferromagnetic composite layers and silicon interlayers with or without hydrogen are studied here by means of X-ray diffraction (XRD), X-ray reflectivity (XRR), IR spectroscopy, and ultra-soft X-ray emission spectroscopy (USXES). The MLNS [(Co45Fe45Zr10)35(Al2O3)65/a-Si:H]100 and [(Co45Fe45Zr10)35(Al2O3)65/a-Si]120 were deposited on the substrate Si(100) by ion-beam sputtering of two targets, where the first target was a plate of Co45Fe45Zr10 alloy with Al2O3 inserts, and the second target was a single-crystal silicon. Our results show that the iron (FeSi2) and cobalt (CoSi, CoSi2) silicides are formed at the interfaces of the composite metal-containing layer/silicon interlayer. It is demonstrated that the metal clusters of composite layers and interface silicides are partially oxidized to form iron, cobalt, and silicon oxides together with zirconium silicate. Due to the formation of silicides at the interfaces, the composition of MLNS superstructures becomes more complex, and their periods are significantly reduced (down to 5–6 nm) compared to the nominal values of bilayers of about 6.9 nm.

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Yudkina, A. V., E. A. Kovalenko, A. V. Endutkin, E. P. Panferova, A. A. Kirilenko, A. A. Kokhanenko y D. O. Zharkov. "Factors Affecting the Stability of the Trimer of 2'-deoxyuridine-5'-triphosphate Nucleotide Hydrolase from <i>Escherichia coli</i>". Молекулярная биология 57, n.º 2 (1 de marzo de 2023): 330–39. http://dx.doi.org/10.31857/s0026898423020246.

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To prevent erroneous incorporation of dUMP into DNA from the dUTP metabolic pool, all living cells contain 2′-deoxyuridine-5′-triphosphate nucleotide hydrolase (Dut), an enzyme that hydrolyzes dUTP to dUMP and pyrophosphate. Dut is considered a promising pharmacological target for antimetabolite therapy. Enzymatically active Dut is a trimer that binds the substrate at the interface between the subunits. Here we use high-speed nanoscale differential scanning fluorometry (nanoDSF) to study how various physicochemical factors affect the stability of the E. coli Dut trimer. Unlike for monomeric proteins, thermal denaturation of Dut occurred in two stages, the first of which corresponds to the dissociation of the trimer to monomeric subunits. Hydrophobic interactions and hydrogen bonds at the interfaces between subunits contributed most to trimer stabilization. The Dut trimer was partially stabilized upon binding of nucleotide ligands. In general, nanoDSF is a convenient assay for screening low molecular weight compounds for their ability to destabilize the active Dut trimer.

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Tian, Ya-Ming, Wagner Silva, Ruth M. Gschwind y Burkhard König. "Accelerated photochemical reactions at oil-water interface exploiting melting point depression". Science 383, n.º 6684 (16 de febrero de 2024): 750–56. http://dx.doi.org/10.1126/science.adl3092.

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Water can accelerate a variety of organic reactions far beyond the rates observed in classical organic solvents. However, using pure water as a solvent introduces solubility constraints that have limited the applicability of efficient photochemistry in particular. We report here the formation of aggregates between pairs of arenes, heteroarenes, enamines, or esters with different electron affinities in an aqueous medium, leading to an oil-water phase boundary through substrate melting point depression. The active hydrogen atoms in the reactants engage in hydrogen bonds with water, thereby accelerating photochemical reactions. This methodology realizes appealingly simple conditions for aqueous coupling reactions of complex solid molecules, including complex drug molecules that are poorly soluble in water.

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Reddi, Ravikumar, Kiran Kumar Singarapu, Debnath Pal y Anthony Addlagatta. "The unique functional role of the C–H⋯S hydrogen bond in the substrate specificity and enzyme catalysis of type 1 methionine aminopeptidase". Molecular BioSystems 12, n.º 8 (2016): 2408–16. http://dx.doi.org/10.1039/c6mb00259e.

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Unique C–H⋯S hydrogen bonding interactions allow nature to attain recognition specificity between molecular interfaces where there is no apparent scope for classical hydrogen bonding or polar interactions.

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Mas-Vinyals, Anna, Joan Gilabert-Porres, Laura Figueras-Esteve y Salvador Borrós. "Improving linking interface between collagen-based hydrogels and bone-like substrates". Colloids and Surfaces B: Biointerfaces 181 (septiembre de 2019): 864–71. http://dx.doi.org/10.1016/j.colsurfb.2019.06.046.

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Yasin, Liam y Sam Cooper. "Quantifying Diffusion Across Solid-Solid Interfaces in Electrochemical Cells". ECS Meeting Abstracts MA2023-01, n.º 38 (28 de agosto de 2023): 2280. http://dx.doi.org/10.1149/ma2023-01382280mtgabs.

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Enabling an increased rollout of hydrogen-based technologies requires decarbonisation of both hydrogen production and conversion. Solid Oxide Cells (SOCs), in the form of electrolysers and fuel cells, could play a significant role in achieving this, however lifetime and degradation of SOCs remain major obstacles to commercialisation. Understanding the mechanisms governing ionic transport in ceramics is important to improving the performance and durability of SOCs. Properties such as the oxygen tracer diffusivity, , can be measured by Isotopic Exchange Depth Profiling (IEDP) as developed by Kilner et al. [1]. This method has, so far, primarily been used to characterise the properties of single materials; however, SOCs are multilayer devices with solid-solid interfaces that may also affect transport. Some investigations into the diffusion behaviour across multiple layers using the IEDP technique have been done in thin film samples [2][3]. Profiles obtained from these studies appear to show an abrupt concentration drop at the interface between certain materials, indicating an interface which significantly impacts the diffusion behaviour (and by extension the overall cell performance). However, no attempt was made to quantify this interface effect with a theoretical modelling approach. A finite-difference model for diffusion in a system containing multiple layers with interfaces is developed. It numerically solves Fick’s second law of diffusion with various boundary conditions. This model can be used to fit experimental data obtained from tracer diffusion SIMS data, yielding new way of quantifying interfacial resistance. A new interfacial resistance parameter, , has been defined, which quantifies the magnitude of concentration drop across any given interface and thus offers a universal way of numerically characterising resistance to diffusion. The validity of the developed method has been experimentally tested in samples containing layers of lanthanum strontium cobalt ferrite (LSCF) and gadolinium-doped ceria (GDC), a commonly used system in SOCs. Initial data from tracer diffusion experiments as seen in Figure 1 have shown the presence of a significant concentration drop at the interface of a LSCF-GDC stack which can be fitted to the numerical model developed by the authors. This approach is used to measure the changing interface properties under various ageing conditions, as well as the influence of interlayers and material selection on the interfacial resistances both in SOC and other diffusion systems. [1] J. A. Kilner, B. C. H. Steele, and L. Ilkov. Oxygen self-dffusion studies using negative-ion secondary ion mass-spectrometry (sims). Solid State Ionics, 12(MAR):89-97, 1984. [2] K. Develos-Bagarinao, H. Yokokawa, H. Kishimoto, T. Ishiyama, K. Yamaji, and T. Horita. Elucidating the origin of oxide ion blocking effects at gdc/srzr(y)o-3/ysz interfaces. Journal of Materials Chemistry A, 5(18):8733-8743, 2017. [3] Katherine Develos-Bagarinao, Haruo Kishimoto, Jeffrey De Vero, Katsuhiko Yamaji, and Teruhisa Horita. Effect of la0.6sr0.4co0.2fe0.8o3-delta microstructure on oxygen surface exchange kinetics. Solid State Ionics, 288:6-9, 2016. Fig. 1. Oxygen isotopic fraction data of an LSCF layer deposited on a GDC substrate and annealed in Oxygen-18 atmosphere at 650 C for 1h obtained using cross-sectional SIMS (left) and fit of the data using the multi-layer diffusion model developed by the authors (right). Figure 1

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Zhu, Wen, Peitang Zhao, Haiyan Lu y Fangzhen Zuo. "Tudy on hydrogen release mechanism of package shell". Advances in Engineering Technology Research 1, n.º 2 (23 de septiembre de 2022): 382. http://dx.doi.org/10.56028/aetr.1.2.382.

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In this paper, the hydrogen release amount of SiC particle reinforced aluminum matrix composite (SiCp/Al) base plate, titanium alloy enclosure and its packaging shell was studied, the influence of substrate surface morphology on the hydrogen storage state of the coating was analyzed, and the hydrogen release mechanism of the packaging shell was discussed. The results show that the gold-plated SiCp/Al composite is the main source of hydrogen release from the package shell, and its complex surface morphology leads to different hydrogen storage states of the coating. At the early stage of baking, the hydrogen storage release is mainly due to micropores and interface defects, which is the main reason for the large amount and dispersion of hydrogen release from the package shell. Continuous baking is mainly stable release of lattice hydrogen storage, resulting in stable and discrete release of hydrogen.

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Zhu, Wen, Peitang Zhao, Haiyan Lu y Fangzhen Zuo. "Tudy on hydrogen release mechanism of package shell". Advances in Engineering Technology Research 2, n.º 1 (23 de septiembre de 2022): 382. http://dx.doi.org/10.56028/aetr.2.1.382.

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In this paper, the hydrogen release amount of SiC particle reinforced aluminum matrix composite (SiCp/Al) base plate, titanium alloy enclosure and its packaging shell was studied, the influence of substrate surface morphology on the hydrogen storage state of the coating was analyzed, and the hydrogen release mechanism of the packaging shell was discussed. The results show that the gold-plated SiCp/Al composite is the main source of hydrogen release from the package shell, and its complex surface morphology leads to different hydrogen storage states of the coating. At the early stage of baking, the hydrogen storage release is mainly due to micropores and interface defects, which is the main reason for the large amount and dispersion of hydrogen release from the package shell. Continuous baking is mainly stable release of lattice hydrogen storage, resulting in stable and discrete release of hydrogen.

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26

Fukumoto, Michihisa, Kano Nakajima y Hiroki Takahashi. "Formation of LaNi5 Hydrogen Storage Alloy by Electrodeposition of La Using Molten Salt". Coatings 12, n.º 9 (31 de agosto de 2022): 1268. http://dx.doi.org/10.3390/coatings12091268.

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A hydrogen storage alloy was formed by electrodepositing La using a molten salt. La was electrodeposited using Ni as a substrate in NaCl-KCl-5.0 mol% LaF3 molten salt at electrodeposition temperatures of 750 °C and 900 °C. The electrodeposition potential was −2.25 V. The LaNi5 hydrogen storage alloy was then prepared by the electrodeposition of La and the mutual diffusion of the Ni substrate. As a result, it was clarified that La can be electrodeposited by using a molten salt. Single-phase LaNi5 was produced at 750 °C rather than at 900 °C. It became possible to uniformly form LaNi5, an intermetallic compound, on the substrate surface. The prepared hydrogen storage alloy was exposed to Ar-10%H2 to store hydrogen; at this time, hydrogen was stored by changing the sample temperature. The discharged hydrogen was measured by a gas sensor. It was clarified that the hydrogen storage and hydrogen discharge were the highest in the sample obtained by electrodepositing La for 1 h at 750 °C. LaNi5 formed by electrodeposition showed hydrogen storage properties, and this method was found to be effective even for samples with complex shapes.

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27

Haupt, Melina, Matthew P. Blakeley, Stuart J. Fisher, Sax A. Mason, Jon B. Cooper, Edward P. Mitchell y V. Trevor Forsyth. "Binding site asymmetry in human transthyretin: insights from a joint neutron and X-ray crystallographic analysis using perdeuterated protein". IUCrJ 1, n.º 6 (21 de octubre de 2014): 429–38. http://dx.doi.org/10.1107/s2052252514021113.

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Human transthyretin has an intrinsic tendency to form amyloid fibrils and is heavily implicated in senile systemic amyloidosis. Here, detailed neutron structural studies of perdeuterated transthyretin are described. The analyses, which fully exploit the enhanced visibility of isotopically replaced hydrogen atoms, yield new information on the stability of the protein and the possible mechanisms of amyloid formation. Residue Ser117 may play a pivotal role in that a single water molecule is closely associated with the γ-hydrogen atoms in one of the binding pockets, and could be important in determining which of the two sites is available to the substrate. The hydrogen-bond network at the monomer–monomer interface is more extensive than that at the dimer–dimer interface. Additionally, the edge strands of the primary dimer are seen to be favourable for continuation of the β-sheet and the formation of an extended cross-β structure through sequential dimer couplings. It is argued that the precursor to fibril formation is the dimeric form of the protein.

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28

Sadananda, Kuntimaddi, Jung Ho Yang, Nagaraja Iyyer, Nam Phan y Anisur Rahman. "Sacrificial Zn–Ni coatings by electroplating and hydrogen embrittlement of high-strength steels". Corrosion Reviews 39, n.º 6 (25 de octubre de 2021): 487–517. http://dx.doi.org/10.1515/corrrev-2021-0038.

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Abstract A review of sacrificial Zn–Ni electroplating coatings on high-strength steels is presented. These steels are used for heavy structural applications such as landing gears, etc., that are subjected to high stresses and corrosive environments in service. The electroplating process involving aqueous electrolytes invariably produces hydrogen. The emitted hydrogen can diffuse into substrate steel, contributing to the delayed failures by hydrogen embrittlement. Microstructural inhomogeneities arising from the heat treatments and defects produced during coatings and those inherently present in the steels can trap hydrogen emitted during plating. Dissolved and trapped hydrogen can slowly diffuse to the stress concentrations or crack tips, contributing to the delayed structural failures. Baking after plating helps to eliminate hydrogen to some extent, though it may introduce some thermomechanical stresses at the bimaterial interfaces. This review discusses a) the current state of sacrificial Zn–Ni coatings, b) their protection against corrosion of the substrate, c) the associated hydrogen embrittlement predominately under cyclic loads, and d) recent advances in terms of the compositionally modulated coatings for enhanced protection.

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29

Lee, Jae Kyoo, Hyun Soo Han, Settasit Chaikasetsin, Daniel P. Marron, Robert M. Waymouth, Fritz B. Prinz y Richard N. Zare. "Condensing water vapor to droplets generates hydrogen peroxide". Proceedings of the National Academy of Sciences 117, n.º 49 (23 de noviembre de 2020): 30934–41. http://dx.doi.org/10.1073/pnas.2020158117.

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It was previously shown [J. K. Leeet al.,Proc. Natl. Acad. Sci. U.S.A., 116, 19294–19298 (2019)] that hydrogen peroxide (H2O2) is spontaneously produced in micrometer-sized water droplets (microdroplets), which are generated by atomizing bulk water using nebulization without the application of an external electric field. Here we report that H2O2is spontaneously produced in water microdroplets formed by dropwise condensation of water vapor on low-temperature substrates. Because peroxide formation is induced by a strong electric field formed at the water–air interface of microdroplets, no catalysts or external electrical bias, as well as precursor chemicals, are necessary. Time-course observations of the H2O2production in condensate microdroplets showed that H2O2was generated from microdroplets with sizes typically less than ∼10 µm. The spontaneous production of H2O2was commonly observed on various different substrates, including silicon, plastic, glass, and metal. Studies with substrates with different surface conditions showed that the nucleation and the growth processes of condensate water microdroplets govern H2O2generation. We also found that the H2O2production yield strongly depends on environmental conditions, including relative humidity and substrate temperature. These results show that the production of H2O2occurs in water microdroplets formed by not only atomizing bulk water but also condensing water vapor, suggesting that spontaneous water oxidation to form H2O2from water microdroplets is a general phenomenon. These findings provide innovative opportunities for green chemistry at heterogeneous interfaces, self-cleaning of surfaces, and safe and effective disinfection. They also may have important implications for prebiotic chemistry.

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YAMADA, Takeshi, Yoshiki NOBUHARA, Masayuki SAKIHARA, Hiroyuki HIRAKATA y Kohji MINOSHIMA. "302 Effect of Hydrogen on Interface Fracture Toughness between Nano-film and Substrate". Proceedings of Conference of Kansai Branch 2009.84 (2009): _3–2_. http://dx.doi.org/10.1299/jsmekansai.2009.84._3-2_.

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31

Rai, Amrita, Johann P. Klare, Patrick Y. A. Reinke, Felix Englmaier, Jörg Fohrer, Roman Fedorov, Manuel H. Taft et al. "Structural and Biochemical Characterization of a Dye-Decolorizing Peroxidase from Dictyostelium discoideum". International Journal of Molecular Sciences 22, n.º 12 (10 de junio de 2021): 6265. http://dx.doi.org/10.3390/ijms22126265.

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A novel cytoplasmic dye-decolorizing peroxidase from Dictyostelium discoideum was investigated that oxidizes anthraquinone dyes, lignin model compounds, and general peroxidase substrates such as ABTS efficiently. Unlike related enzymes, an aspartate residue replaces the first glycine of the conserved GXXDG motif in Dictyostelium DyPA. In solution, Dictyostelium DyPA exists as a stable dimer with the side chain of Asp146 contributing to the stabilization of the dimer interface by extending the hydrogen bond network connecting two monomers. To gain mechanistic insights, we solved the Dictyostelium DyPA structures in the absence of substrate as well as in the presence of potassium cyanide and veratryl alcohol to 1.7, 1.85, and 1.6 Å resolution, respectively. The active site of Dictyostelium DyPA has a hexa-coordinated heme iron with a histidine residue at the proximal axial position and either an activated oxygen or CN− molecule at the distal axial position. Asp149 is in an optimal conformation to accept a proton from H2O2 during the formation of compound I. Two potential distal solvent channels and a conserved shallow pocket leading to the heme molecule were found in Dictyostelium DyPA. Further, we identified two substrate-binding pockets per monomer in Dictyostelium DyPA at the dimer interface. Long-range electron transfer pathways associated with a hydrogen-bonding network that connects the substrate-binding sites with the heme moiety are described.

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32

Ofrim, Bogdan, Gheorghe Brezeanu, Florin Draghici y Ion Rusu. "High Temperature Hydrogen Sensor Based on Silicon Carbide (SiC) MOS Capacitor Structure". Materials Science Forum 778-780 (febrero de 2014): 1054–57. http://dx.doi.org/10.4028/www.scientific.net/msf.778-780.1054.

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MOS capacitor devices based on silicon carbide (SiC) are largely used as hydrogen detectors in high temperature and chemically reactive environments. A SiC MOS capacitor structure used as hydrogen sensor is analyzed by extensive simulations. The sensitivity to hydrogen detection, stability to temperature variation and dependence on interface states concentration are evaluated. The effects of structure parameters on sensors performance are also investigated. Results show that the oxide layer type and thickness and the SiC polytype have a significant influence on the detectors performance. The proposed optimum structure for high temperature hydrogen detection is based on 3C-SiC substrate and 10nm TiO2 layer. In accordance with the simulations results, three types of masks are designed for the fabrication of SiC MOS capacitor structures.

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33

Nevolin, V. N., R. I. Romanov, D. V. Fominski, O. V. Rubinkovskaya, A. A. Soloviev y V. Yu Fominski. "Nanostructured MoS3/WSe2 thin-film photocathode for efficient water splitting under light illumination". Perspektivnye Materialy, n.º 8 (2020): 5–18. http://dx.doi.org/10.30791/1028-978x-2020-8-5-18.

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The influence of the chemical state of the WOу thin-film precursor on the formation of WSe2 nanofilms under rapid selenization on a glassy-carbon substrate at 900°C was studied. Amorphous molybdenum sulfide (MoSx~3), which has high catalytic activity in the electrochemical hydrogen evolution reaction, was prepared on the surface of the WSe2 films by pulsed laser deposition. It was shown that the composition of the WOу precursors had a significant effect on the morphology of WSe2 nanolayers, and this characteristic largely determined the efficiency of hydrogen evolution by the MoS3/WSe2 heterostructure upon photo-activated water splitting. The most efficient hydrogen evolution was found for the MoS3/WSe2 photocathode that contained WSe2 in the form of petal crystals of ~ 50 nm thickness and these petals were oriented perpendicular to the substrate surface. A theoretical analysis of the possible effect of synergetic interaction at the MoS3/WSe2 interface on the efficiency of hydrogen formation was carried out. Calculations using the density functional theory showed that MoS3 clusters can increase the efficiency of the hydrogen evolution reaction in contact with surface areas of WSe2 nanocrystals possessing different atomic packing.

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34

Godbole, Mukund J., Anthony J. Pedraza, Douglas H. Lowndes y Edward A. Kenik. "Laser-induced interface reactions of copper thin films on sapphire substrates". Journal of Materials Research 4, n.º 5 (octubre de 1989): 1202–8. http://dx.doi.org/10.1557/jmr.1989.1202.

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The interface of a copper-sapphire couple that was irradiated with a nanosecond pulsed-exeimer laser was studied by transmission electron microscopy. Deposited layers of 30 or 100 nm thickness were laser treated with energy densities in the range of 0.5 to 0.75 J/cm2. Two different atmospheres were used during these treatments, viz., air or a mixture of argon-4 vol. % hydrogen. The copper film and a thin alumina layer were melted by the laser pulse. Two well differentiated regions could be observed in the modified layer. The region closer to the unmodified substrate consisted of epitaxially regrown alumina with crystallites misoriented up to 10° relative to the substrate sapphire orientation, while precipitate particles could be seen closer to the resolidified copper. The nature of the precipitates generated in the second region was dependent on the atmosphere present during the treatment. In air a trirutile-like compound was obtained which is either oxygen or copper deficient. In an argon atmosphere a compound having a hexagonal structure closely related to sapphire was observed, where copper substituted for some aluminum. These observations are in agreement with a previously developed mathematical model that predicts melting of a thin substrate layer.

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35

Chen, Jiayao, Jing Li, Lirong Xu, Wei Hong, Yuzhao Yang y Xudong Chen. "The Glass-Transition Temperature of Supported PMMA Thin Films with Hydrogen Bond/Plasmonic Interface". Polymers 11, n.º 4 (2 de abril de 2019): 601. http://dx.doi.org/10.3390/polym11040601.

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The interfacial effect is one of the significant factors in the glass-transition temperature (Tg) of the polymeric thin film system, competing against the free surface effect. Herein, the Tgs of poly (methyl methacrylate) (PMMA) films with different thicknesses and substrates are studied by fluorescence measurements, focusing on the influence of interfacial effects on the Tgs. The strong interaction between PMMA and quartz substrate leads to increased Tgs with the decreased thickness of the film. The plasmonic silver substrate causes enhanced fluorescence intensity near the interface, resulting in the delayed reduction of the Tgs with the increasing film thickness. Moreover, as a proof of the interface-dependent Tgs, hydrogen bonds of PMMA/quartz and molecules orientation of PMMA/silver are explored by the Raman spectroscopy, and the interfacial interaction energy is calculated by the molecular dynamics simulation. In this study, we probe the inter-relationship between the interfacial interactions arising from the different substrates and the Tg behavior of polymer thin films.

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36

Groza, A., A. Surmeian, C. Diplasu, C. Luculescu, C. Negrila y M. Ganciu. "Generation of Porous Alumina Layers in a Polydimethylsiloxane/Hydrogen Peroxide Medium on Aluminum Substrate in Corona Discharges". Journal of Nanomaterials 2014 (2014): 1–6. http://dx.doi.org/10.1155/2014/578720.

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The porous alumina (Al2O3) layer obtained at the interface between polydimethylsiloxane/hydrogen peroxide medium and aluminum substrate under charged and neutral species injection produced in negative corona discharges in air at atmospheric pressure is analyzed by different methods in this paper. The scanning electron microscopy investigations showed the uniform distribution of the pores formed in the alumina layer and their columnar structures. Both energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) measurements indicate that during the anodization process of the aluminum in the polydimethylsiloxane/hydrogen peroxide medium in corona discharge the incorporation of silicon in the structure of the alumina layer is possible.

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37

González-Henríquez, Carmen M., Diego F. Veliz-Silva, Mauricio A. Sarabia-Vallejos, Adolfo del Campo-García y Juan Rodríguez-Hernández. "Micrometric Wrinkled Patterns Spontaneously Formed on Hydrogel Thin Films via Argon Plasma Exposure". Molecules 24, n.º 4 (19 de febrero de 2019): 751. http://dx.doi.org/10.3390/molecules24040751.

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The generation of microstructured patterns on the surface of a specific polymeric material could radically improve their performance in a particular application. Most of the interactions with the environment occur at the material interface; therefore, increasing the exposed active surface considerably improves their range of application. In this article, a simple and reliable protocol to form spontaneous wrinkled patterns using a hydrogel layer is reported. For this purpose, we took advantage of the doctor blade technique in order to generate homogenous films over solid substrates with controlled thickness and large coverage. The hydrogel wrinkle formation involves a prepolymerization step which produces oligomers leading to a solution with increased viscosity, enough for doctor blade deposition. Subsequently, the material was exposed to vacuum and plasma to trigger wrinkled pattern formation. Finally, a UV-polymerization treatment was applied to fix the undulations on top. Interestingly, the experimental parameters allowed us to finely tune the wrinkle characteristics (period, amplitude, and orientation). For this study, two main aspects were explored. The first one is related to the role of the substrate functionalization on the wrinkle formation. The second study correlates the deswelling time and its relationship with the dimensions and distribution of the wrinkle pattern. In the first batch, four different 3-(trimethoxysilyl)propyl methacrylate (TSM) concentrations were used to functionalize the substrate in order to enhance the adhesion between hydrogel film and the substrate. The wrinkles formed were characterized in terms of wrinkle amplitude, wavelength, pattern roughness, and surface Young modulus, by using AFM in imaging and force spectroscopy modes. Moreover, the chemical composition of the hydrogel film cross-section and the effect of the plasma treatment were analyzed with confocal Raman spectroscopy. These results demonstrated that an oxidized layer was formed on top of the hydrogel films due to the exposure to an argon plasma.

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38

WONG, K. C., P. C. WONG, Y. S. LI y K. A. R. MITCHELL. "CHEMICAL PROPERTIES OF A Nb/Zr INTERFACE STUDIED BY XPS". Surface Review and Letters 04, n.º 01 (febrero de 1997): 33–37. http://dx.doi.org/10.1142/s0218625x97000067.

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A film of niobium (~ 15 Å thick) deposited under ultrahigh vacuum (UHV) conditions on polycrystalline zirconium was studied by x-ray photoelectron spectroscopy (XPS) as it was taken through a series of sequential treatments. The Nb–Zr interface, associated with a Nb 3 d 5/2 peak at 203.4 eV, is indicated to passivate the underlying Zr to oxygen and hydrogen plasma treatments, which in the absence of Nb would yield substantial oxidation. On heating to 500°C, the pure metallic Nb 3 d 5/2 component at 202.2 eV appears, and this change is accompanied by removal of the passivation effect on the substrate.

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39

Abdesselem, S., A. Ouhab y M. S. Aida. "Influence de la température de substrat sur la croissance et les propriétés des films minces de silicium amorphe déposés par pulvérisation cathodique". Canadian Journal of Physics 81, n.º 11 (1 de noviembre de 2003): 1293–302. http://dx.doi.org/10.1139/p03-101.

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We deposit thin films of a-Si:H by RF diode spray on substrate with temperatures varying from 200 to 500 °C. Knowing that this deposition method is violent when compared with the plasma-assisted deposition method, we have used low RF power to limit the energy of the Ar ions bombarding the surface of the growing film. Characterization of the films by UVvisible absorption spectroscopy suggests that the influence of the substrate temperature can be classified into three different regimes: (i) low temperature, Ts < 300 °C: the films show a strong disorder, the hydrogen is bound only in the polyhydric configuration; (ii) intermediate temperature, 300 °C < Ts < 400 °C: film growth is rapid, the films present a lower defect density; this may be the best regime to make good quality a-Si:H films using the spraying method; (iii) high temperature, Ts > 400 °C: the films are more organized, but less hydrogenated. The substrate temperature influences the film properties by modifying the growing mechanism through a control of the reactions taking place at the plasmasubstrate interface, where the hydrogen dynamics play a fundamental role.[Journal translation]

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40

Hultquist, Gunnar, C. Anghel y P. Szakàlos. "Effects of Hydrogen on the Corrosion Resistance of Metallic Materials and Semiconductors". Materials Science Forum 522-523 (agosto de 2006): 139–46. http://dx.doi.org/10.4028/www.scientific.net/msf.522-523.139.

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For long time it is known that protons in aqueous solutions have a detrimental effect on metallic materials. Relatively recently, it has also been observed in aqueous solution that the pitting corrosion resistance of Cr, stainless steel 304 and 310 decreases and the anodic dissolution rate increases due to the presence of hydrogen in the metal. In gas phase a high oxidation rate has been observed for hydrogen containing Cr and Fe. Hydrogen in the substrate can also enhance the oxidation of Fe in SS 316 and As in GaAs. All these results suggest enhanced dissolution in aqueous solution and enhanced oxide growth at the oxide/gas interface in gas phase oxidation due to hydrogen promoted outward-transport of substrate components. A possible mechanism for such out-transport is an increased metal ion diffusivity in the metal-oxide due to a high abundance of metal ion vacancies generated by hydrogen. In contrast to all the above examples, also positive effects of hydrogen have been identified under certain conditions. In an attempt to understand both the negative and the positive effects the concept of a beneficial, balanced oxide growth is used. In this concept a certain amount of hydrogen can be beneficial in the oxidation by improving the balance between oxygen-ion and metalion transport, leading to more dense and protective oxides. Depending on the temperature, H2 in air is considered as either a sink or a source for hydrogen in materials.

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Yu, Han, Qiaohong Xiao, Guilin Qi, Feixiang Chen, Biyue Tu, Suo Zhang, Yinping Li, Yun Chen, Hui Yu y Peng Duan. "A Hydrogen Bonds-Crosslinked Hydrogels With Self-Healing and Adhesive Properties for Hemostatic". Frontiers in Bioengineering and Biotechnology 10 (14 de abril de 2022). http://dx.doi.org/10.3389/fbioe.2022.855013.

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Hydrogels with adhesive properties have the potential for rapid haemostasis and wound healing in uncontrolled non-pressurized surface bleeding. Herein, a typical hydrogen bond-crosslinked hydrogel with the above functions was constructed by directly mixing solutions of humic acid (HA) and polyvinylpyrrolidone (PVP), in which the HA worked as a crosslinking agent to form hydrogen bonds with the PVP. By altering the concentration of HA, a cluster of stable and uniform hydrogels were prepared within 10 s. The dynamic and reversible nature of the hydrogen bonds gave the HA/PVP complex (HPC) hydrogels injectability and good flexibility, as well as a self-healing ability. Moreover, the numerous functional groups in the hydrogels enhanced the cohesion strength and interaction on the interface between the hydrogel and the substrate, endowing them with good adhesion properties. The unique chemical composition and cross-linking mechanism gave the HPC hydrogel good biocompatibility. Taking advantage of all these features, the HPC hydrogels obtained in this work were broadly applied as haemostatic agents and showed a good therapeutic effect. This work might lead to an improvement in the development of multifunctional non-covalent hydrogels for application to biomaterials.

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42

Yi, Bo, Tianjie Li, Boguang Yang, Sirong Chen, Jianyang Zhao, Pengchao Zhao, Kunyu Zhang, Yi Wang, Zuankai Wang y Liming Bian. "Surface hydrophobization of hydrogels via interface dynamics-induced network reconfiguration". Nature Communications 15, n.º 1 (3 de enero de 2024). http://dx.doi.org/10.1038/s41467-023-44646-5.

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AbstractEffective and easy regulation of hydrogel surface properties without changing the overall chemical composition is important for their diverse applications but remains challenging to achieve. We report a generalizable strategy to reconfigure hydrogel surface networks based on hydrogel–substrate interface dynamics for manipulation of hydrogel surface wettability and bioadhesion. We show that the grafting of hydrophobic yet flexible polymeric chains on mold substrates can significantly elevate the content of hydrophobic polymer backbones and reduce the presence of polar groups in hydrogel surface networks, thereby transforming the otherwise hydrophilic hydrogel surface into a hydrophobic surface. Experimental results show that the grafted highly dynamic hydrophobic chains achieved with optimal grafting density, chain length, and chain structure are critical for such substantial hydrogel surface network reconfiguration. Molecular dynamics simulations further reveal the atomistic details of the hydrogel network reconfiguration induced by the dynamic interface interactions. The hydrogels prepared using our strategy show substantially enhanced bioadhesion and transdermal delivery compared with the hydrogels of the same chemical composition but fabricated via the conventional method. Our findings provide important insights into the dynamic hydrogel–substrate interactions and are instrumental to the preparation of hydrogels with custom surface properties.

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Perez, Edward, Linda G. Cima, David Miller y Edward W. Merrill. "Bilayer Composite Hydrogels for Corneal Prostheses". MRS Proceedings 252 (1991). http://dx.doi.org/10.1557/proc-252-375.

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ABSTRACTA two-layer composite material composed of a thin-layer of corneal tissue and a synthetic polyethylene oxide (PEO) hydrogel is described. The material is designed to provide a suitable substrate for corneal epithelial cell growth while maintaining the desirable characteristics of hydrogels, i.e. clarity, flexibility, and ability to allow diffusive flow of nutrients. The gels are synthesized via electron irradiation induced crosslinking of an aqueous solution of PEO onto a thin layer of collagenous tissue substrate. light microscopic studies indicate that the interface between the corneal tissue and PEO gel appears well adherent with no gaps in the interface. SEM studies of the material surface show an architecture similar to that of normal corneal tissue. Surface analytical techniques were used to identify amino-acids covalently bound to the gel at the gel/collagen interface after the proteinaceous material was removed. ESCA survey scans identified the presence of nitrogen on exposed gel/collagen interfaces and amino acid labelling confirmed the presence of amino acids. ATR-IR studies identifed increased absorption for the gel collagen interfaces at 1640 cm− 1 and 1540 cm−1 indicative of bound amino acids.

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44

Matsumura, Mikiya, Takahisa Tanaka y Ken UCHIDA. "Experimental study on shallow and deep dopant properties at the interface of PtO_x/ZnO Schottky diodes". Japanese Journal of Applied Physics, 14 de febrero de 2022. http://dx.doi.org/10.35848/1347-4065/ac54f3.

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Abstract The donor properties at the interface of the PtOx/ZnO Schottky diodes on hydrothermally grown ZnO were investigated. From the capacitance-voltage (C-V) characteristics of the diode and Hall effect measurements of the bulk substrate, we revealed that the carrier concentration at the ZnO Schottky diodes interface is much higher than that in the bulk. By utilizing the C-V characteristics and the deep level transient spectroscopy (DLTS), we demonstrated that the interfaces have two kinds of ionized donors; the shallow and deep donors, whose activation energies were 4 meV and 0.33 eV, respectively. The two donors were ionized near the interface, whereas only the low-concentration shallow donors were ionized in the bulk. The shallow and deep donors were assigned to hydrogen interstadials and E3 defects, respectively. Since both the donor types are related to hydrogens, annealing in the oxygen atmosphere was effective to greatly suppress the donor concentration at the diode interface.

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45

Wen, Zhixuan, Teng Zhou, Qian Xu, Weipeng Chen, Weiwen Xin, Xiang-Yu Kong y Lei Jiang. "Functional hydrogel-plastic hybrids inspired by the structural characteristics of mussels". NPG Asia Materials 15, n.º 1 (18 de agosto de 2023). http://dx.doi.org/10.1038/s41427-023-00491-y.

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AbstractShellfish with rigid shells prevent damage to their delicate internal cores, and their soft bonding muscles drive the opening and closing of the shells. This synergism of rigid and soft materials provides shellfish with unique environmental adaptation. Inspired by the structural characteristics of mussels, a riveting layer was introduced into hydrogel-plastic hybrids for bonding hydrogel networks and plastic substrates. The bonding strength of the hydrogel on the polypropylene (PP) substrate was approximately 1.52 MPa, and the interface toughness reached 1450 J m−2. Furthermore, the integration of plastics and microscale hydrogels, as well as abscised or prefabricated hydrogels, could also be fabricated through the same process. By using this strategy, a hydrogel-plastic hybrid-based device with temperature responsiveness and scratch resistance was fabricated and could mimic the basic activities of mussels. This work improves the functional materials used in programmable engineering systems and could facilitate the construction of intelligent robots.

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46

Yates, Heather M. y John O. Williams. "Metal Organic Chemical Vapour Deposition Growth of Epitaxial ZnSe/ZnS Multiple Layered Structures". MRS Proceedings 102 (1987). http://dx.doi.org/10.1557/proc-102-137.

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ABSTRACTZnSe-ZnS multilayers have been prepared by atmospheric. pressure metal organic chemical vapour deposition (M0CVD) using dimethylzinc, hydrogen sulphide and hydrogen selenide. Layer thicknesses down to 500Å have been obtained and the interfaces, as measured by secondary ion mass spectroscopy (SIMS) and electron microscopy, are regular. A notable improvement in interface abruptness was observed with better control of experimental procedures and more especially with the growth of a ZnSe buffer layer between the GaAs(100) substrate and multilayers.

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47

Ren, Xingrong, Jiayi Zhang, Fan Yang, Hong Xu, Gaoyang Guo y Yunbing Wang. "Enzyme‐Immobilized Surface‐Catalyzed Cross‐Linking: Creating Multifunctional Double Network Hydrogel Coatings on Diverse Substrates". Advanced Functional Materials, 7 de marzo de 2024. http://dx.doi.org/10.1002/adfm.202312465.

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AbstractHydrogel coatings, with natural tissue‐like mechanical and biological compatibility, demonstrate promise for bulk material applications. However, existing coating methods lack efficiency and control, especially when dealing with complex geometries, diverse substrate materials, and varying sizes. In this study, an enzyme‐immobilized surface‐catalyzed cross‐link approach is proposed for the growth of hydrogel coatings on multiple substrates, accommodating various materials and shapes. The hydrogel coating is formed through the catalytic action of interface‐immobilized enzymes, which induce the crosslinking of hyaluronic acid, and its mechanical properties are further enhanced by introducing a secondary polyacrylamide network. This approach enables the controlled growth of conformal double network hydrogel coatings with a desired thickness on a wide range of substrate surfaces and devices. Notably, the hydrogel coating exhibits remarkable lubricity and anti‐thrombotic properties, especially desire for medical intervention devices. This advancement offers a universal route to impart biocompatible soft interfaces to bulk materials or devices.

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Zhang, Xiaoxiang, Yuxuan Guo y Congwei Wang. "Multi-interface engineering of nickel-based electrocatalysts for alkaline hydrogen evolution reaction". Energy Materials, 2024. http://dx.doi.org/10.20517/energymater.2023.115.

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High gravimetric energy density and zero carbon emission of hydrogen have motivated hydrogen energy to be an attractive alternative to fossil fuels. Electrochemical water splitting in alkaline medium, driven by green electricity from renewable sources, has been mentioned as a potential solution for sustainable hydrogen production. Hydrogen evolution reaction (HER), as a cathodic half-reaction of water splitting, requires additional overpotential to obtain protons via water adsorption/dissociation, suffering from slow kinetics in alkaline solution. Robust and active nickel (Ni)-based electrocatalyst is a promising candidate for achieving precious-metal comparable performance owing to its platinum-like electronic structures with more efficient electrical power consumption. Various modification strategies have been explored on Ni-based catalysts, among which multi-interface engineering is one of the most effective routines to optimize both the intrinsic activity of Ni-based electrocatalysts and the extrinsic stacked component limitations. Herein, we systematically summarize the recent progress of multi-interface engineering of Ni-based electrocatalysts to improve their alkaline HER catalytic activity. The origin of sluggish alkaline HER kinetics is first discussed. Subsequently, three kinds of interfaces, geometrically and reactively, conductive substrate/electrocatalyst interface, electrocatalyst internal heterointerface, and electrocatalyst/electrolyte interface, were cataloged and discussed on their contribution mechanisms toward alkaline HER. Particular focuses lie on the microstructural and electronic modulation of key intermediates with energetically favorable adsorption/desorption behaviors via rationally designed interfaces. Finally, challenges and perspectives for multi-interface engineering are discussed. We hope that this review will be inspiring and beneficial for the exploration of efficient Ni-based electrocatalysts for alkaline water electrolysis.

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Fukuda, K., K. Sakamoto, K. Nagai, T. Sekigawa, S. Yoshida y K. Arai. "A Formation of SiO2/4H-SiC Interface by Oxidizing Deposited Poly-Si and High Temperature Hydrogen Annealing". MRS Proceedings 572 (1999). http://dx.doi.org/10.1557/proc-572-105.

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ABSTRACTA formation of SiO2/4H-SiC interfaces by oxidizing deposited poly-Si on a 4H-SiC substrate and high temperature hydrogen annealing at low pressure ( 8.5×102 Pa ) has been investigated. The oxidation rate of deposited poly-Si was approximately 100 times faster than that of a SiC. Hydrogen annealing more effectively reduced the flat band voltage shift ( ΔVfb ) of the 4H-SiC MOS structure than argon and vacuum annealing. Moreover, the good SiO2/4H-SiC interface was formed because ΔVfb decreased as the oxidation temperature increased.

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50

Newham, George, Joseph Fox, Samuel CT Moorcroft y Stephen D. Evans. "Enzymatic and Catalytic Behaviour of Low-Dimensional Gold Nanomaterials in Modular Nano-composite Hydrogels". Materials Research Express, 6 de junio de 2023. http://dx.doi.org/10.1088/2053-1591/acdc05.

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Abstract Inorganic nanoparticles have long been applied as catalysts and nanozymes with exceptional rate constants arising from their large surface areas. While it is understood that high surface area-to-volume ratios and low average atomic coordination are responsible for their exceptional catalytic properties, these facets remain under exploited in the design of gold nanoparticle catalysts and nanozymes. Here we have developed 3D, 2D, and quasi-1D gold nanoparticles for use as catalysts in reducing 4-nitrophenol by sodium borohydride. Each morphology was characterised with transmission electron microscopy and UV-Vis absorption spectroscopy, while the highest catalytic activity was achieved when the perimeter-to-surface area, or amount of ‘edge’, was maximised. The particles were then applied as nanozymes in modular nano-composite hydrogels. Independent hydrogel tiles containing either the substrate or catalyst were bonded in stacks, which allowed reagent transport across their interface for the colourimetric detection of hydrogen peroxide. This work presents novel insight into the catalytic activity of low-dimension nanoparticles and their potential application in nanozyme-based diagnostic devices.

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