bluuebunny/crossref_metadata_2025 huggingface dataset:
Substrate-Dependent Oxidation with Alkyl Hydroperoxide Mediated By Iron Porphyrin Coordinated By Thiolate
Authors: Higuchi Tsunehiko
Published: February 2020

Alkane and arene hydroxylation by cytochrome P450 is one of the most powerful chemical processes in biological systems.  The highly reactive intermediate in cytochrome P450 catalysis has aroused broad interests and has been the subject for extensive investigations. SR complex successfully created by us is the first synthetic heme thiolate complex that retains its thiolate coordination structure during catalytic oxidation reaction. We have focused on the alkyl hydroperoxide-heme thiolate chemistry. We previously found that SR complex efficiently catalyzed one-electron oxidation of 2,4,6-tri-tert-butylphenol (TBPH) with cumene hydroperoxide (CHPO) or tert-butyl hydroperoxide to afford 2,4,6-tri-tert-butylphenoxyl radical (TBP•). Recently, 2-methyl-1-phenylpropan-2-yl hydroperoxide (MPPH) has been used as a mechanistic probe for O-O bond cleavage mode on catalysis of metal complex.  MPPH is known to give benzyl radical-derived products and acetone via unstable alkoxyl radical in the case of homolytic O-O bond cleavage whereas it simply affords 2-methyl-1-phenyl-2-propanol (MPPOH) in the case of heterolysis. Here we report the substrate oxidation mechanism with CHPO and MPPH catalyzed by SR complex.

    We found that SR complex lost its thiolate coordination after the addition of MPPH (1 equiv. to SR complex) even in the presence of large excess amount of phenol with an electron-withdrawing substituent. On the other hand, the use of TBPH or 2,6-di-tert-butylphenol as a substrate lead to retention of the thiolate coordination.

   Next, equilibrium constant K’ values of THF coordination to SRs were determined by Benesi-Hildebrand plot (inverse of absorption spectral change versus inverse of THF concentration). We plot K’ versus reaction rate since correlation between the two factor was expected. The plot clearly showed that the reaction rate was almost proportionate to K’ value from high linearity of the plot in terms of SR complexes. This result suggests that hydroperoxide coordination step is rate-determining step. Putting together these results, alkyl hydroperoxide-heme-thiolate complex is suggested to be an actual active intermediate.
Multi-Step Energy and Electron Transfer in a 'v-Configured' Supramolecular Bodipy-Azabodipy-Fullerene Triad
Authors: D'Souza Francis , Bandi Venugopal , D'Souza Fiona P. , Gobeze Haptom B.
Published: February 2020

Supramolecular multi-modular donor-acceptor systems are useful for solar-fuel and solar-electricity generation, and also for building optoelectronic devices.  In the present contribution, a novel photosynthetic antenna-reaction center model compound composed of covalently linked BF2-chelated dipyrromethene (BODIPY), BF2-chelated azadipyrromethene (azaBODIPY) and fullerene (C60), in a ‘V-Configuration’, has been newly synthesized and characterized using a multi-step synthetic procedure.1  Optical absorbance and steady-state fluorescence, computational, and electrochemical studies were systematically performed in nonpolar, toluene and polar, benzonitrile solvents to establish the molecular integrity of the triad and establish an energy level diagram revealing different photochemical events.  The geometry obtained by B3LYP/6-31G* calculations revealed the anticipated V-configuration of the BODIPY-azaBODIPY-C60 triad.  The location of the frontier orbitals in the triad tracked the site of electron transfer determined from electrochemical studies.  The different photochemical events originated from 1BODIPY* were realized from the energy level diagram.  Accordingly, 1BODIPY* resulted in competitive ultrafast energy transfer to produce BODIPY-1azaBODIPY*-C60 and electron transfer to produce BODIPY·+-azaBODIPY-C60
·- as major photochemical events.  The charge separated state persisted for few nanoseconds prior populating 3C60
* which in turn revealed an unusual triplet-triplet energy transfer to produce 3azaBODIPY* prior returning to the ground state.  These findings delineate the importance of multi-modular systems in energy harvesting, and more importantly, their utility in building multi-function performing optoelectronic devices.  

V. Bandi, F. P. D’Souza, H. Gobeze, F. D’Souza, Chem. Eur. J. 2015, in press.
Polar Self-Assembled Subphthalocyanine Columnar Stacks
Authors: González-Rodríguez David , Torres Tomas , Guilleme Julia
Published: February 2020

Subphthalocyanines (SubPcs) are singular cone-shaped molecules with unique physicochemical properties that render them promising light-harvesting and/or donor units for photovoltaic and light-emitting applications. We were very interested in studying if such molecules could be organized in columnar stacks, both in solution and liquid-crystalline phases by hydrogen-bonding and p-p stacking interactions. The columnar aggregation of these non-planar molecules with axial dipole moments represents in itself a challenging task. Our motivation comes from the possibility of obtaining supramolecular chiral nanofibers and condensed phases that can be aligned in the presence of electric fields, yielding nanomaterials with permanent polarization and unusual ferroelectric and piezoelectric properties.

Figure 1
Advances in Voltammetric Sensors Using Combinations of Phthalocyanines with Nanoparticles and/or Biomolecules in LB and LbL Films
Authors: Rodriguez-Mendez Maria Luz , Medina-Plaza Cristina , Garcia-Hernandez Celia , Garcia-Cabezon Cristina , Martin-Pedrosa Fernando , Muñoz Raquel , de Saja Jose Antonio
Published: February 2020

Electrochemical sensors have been prepared using a range of materials and using a variety of methods.  The selection of phthalocyanines or nanoparticles as sensing materials in electrochemical sensors was inspired in their electrocatalytic properties1.  In turn, nanostructured sensors prepared using the Langmuir-Blodgett (LB) or the electrostatic Layer-by-Layer (LbL) techniques have the advantage of the enhanced number of active sites that has a reflect in the increase in the intensity. The control of molecular architectures afforded by these techniques can led to the development of a variety of devices where synergy is achieved by combining distinct materials, including organic-inorganic hybrids2.

In this work combinations of phthalocyanines with nanoparticles and/or biomolecules  in LB and LbL films have been developed and their structures have been analyzed. The films have been used as voltammetric sensors for the detection of compounds of interest in the food industry (i.e. phenols or organic acids). The role of the molecular interactions in the electrocatalytic properties or as biomimetic systems to immobilize biomolecules has been studied and the existence of synergistic effects has been evidenced. For instance, the combination of phthalocyanines with gold nanoparticles in LB films produced an increase in the sensitivity towards phenols  and detection limits of 10-7 mol.L-1 were attained. Similar detection limits could be obtained by combining phthalocyanines with silver nanoparticles in LbL films. LB and LbL films combining phthalocyanines and amphiphilic molecules provided biomimetic environments where enzymes could preserve their functionality. Detection limits as low as 10-8 mol.L-1 towards phenols were attained.

References:

1M.L. Rodríguez-Méndez,  C. Medina, J.A. de Saja, C. Apetrei, R. Muñoz sensor arrays based on phthalocyanines: new developments on nanostructured and biomimetic electrochemical sensors. In Multisensor systems for chemical analysis: materials and sensors. Eds. L. Lvova, D. Kirsanov, C. Di Natale, and A. Legin. PAN STANFORD PUBLISHING. Chapter 4, 70-109 (2012)

2F. J. Pavinatto, E. G. R. Fernandez, P. Alessio J..C. Constantino,  J. A. de Saja, V. Zucolotto,d O. N. Oliveira Jr. C. Apetrei, M. L. Rodriguez-MendezOptimized architecture for Tyrosinase-containing Langmuir-Blodgett films to detect pyrogallol J. Materials Chemistry 21, 4995-5003 2011

Figure 1: LB film formed by phthalocyanins/amphiphiles and nanoparticles

Figure 1
Power Spectral Density Analysis of the Corrosion Potential Fluctuation of Stainless Steel 316L in Early Stages of Exposure to Caribbean Sea Water
Authors: Espinosa Carlos , Veleva Lucien Petrova , Lopez Juan Luis
Published: February 2020

Stainless Steel 316 L samples were exposed for one month to Caribbean sea water. The fluctuations of the free corrosion potential values (Ecorr at o.c.p.), considered as electrochemical noise (EN), were correlated with the stainless steel pitting corrosion in sea water. Ecorr fluctuation analysis was carried out using the power spectral density (PSD) vs frequency. Figure 1 presents the initially changes of Ecorr with time vs frequency in bilogarithmic scale. For the first three days, the PSD slopes present a negative β exponent (β > 1) at lower frequencies [0.002 – 0.05 Hz], indicating a release of spontaneous energy from the steel surface (corrosion). However, at major frequencies β tends to values close to zero (0.12 – 0.07). At later stages the PSD slopes show a unique value close to zero (0.02 – 0.06), in all range of frequencies [0.002 – 1 Hz]. The exponent β is associated with persistent processes (forces) in data series (216) over time. The calculated Hurst coefficient based on β values suggested that initially the localized corrosion process occurs with the contribution of fractional Brownian motion (fBm) and fractional Gaussian noise (fGn). After the first three days, the Ecorr fluctuations were only dominated by fGn (H≈0.5), which corresponds to the special case when the corrosion occurs at the border between anti-persistent (H<0.5) and persistent (H>0.5) processes. The Ecorr fluctuations were correlated with the data surfaces provided by SEM-EDS and XRD.

Figure 1
Modification of Bbituminous Coatings to Prevent Stress Corrosion Cracking of Carbon Steel
Authors: Ignatenko Vasiliy Eduardovich , Maleeva Marina Alekseevna , Petrunin Maxim Andreevich , Shapagin Alexey Viktorovich , Sherbina Anna Anatol'evna
Published: February 2020

Stress corrosion cracking (SCC) is the most dangerous kind of pipelines corrosion. The SCC appears on the stressed metal due to contact with aggressive media through the rupture of polymer coating. Inhibition of the SCC is one of the urgent tasks of corrosion protection of underground pipelines. The research reports the method of inhibiting the SCC of pipe steels by modification of polymer protective coatings.

With help of slow strain rate test (SSRT) the effect of general corrosion inhibitors and surfactants on the propensity X70 pipe steel to the SCC in aggressive electrolytes has been investigated. The vinyl-containing silane (VS) is shown to be an effective inhibitor of SCC of steel.

The VS has been proposed as a modifying additive to a bitumen coating (DEKOM-GAZ type). Modification of coating should provide both satisfactory adhesion and exit of the SCC inhibiting compounds to electrolyte under film and their adsorption onto the metal surface in the case of mechanical damage or loss of adhesion.

Peel shear test at an angle 90° away from steel plate has been used for evaluation of adhesive properties of modified coating. It has been shown that the additive of the VS does not impair the adhesion of the protective coating. Using FTIR microscopy output of the inhibitor molecules from the polymer matrix to solution and their adsorption onto the metal surface was evaluated. The aqueous extract obtained by exposure of the polymer coating with the addition of the VS in contact with water for 30 days has been investigated. IR-spectra analysis showed that predominantly the VS goes from the coating into solution and adsorbs on the metal surface.

Thus the modified polymer coating, the use of which will prevent the development of SCC of carbon steel, has been developed.
The Evaluation of Corrosion in Construction Materials
Authors: Marquez Andres
Published: February 2020

The evaluation of the Corrosion in construction materials, such as I-beams, angle bars, rebars, steel, among others, provides useful insights about their performance in order to minimize degradation, weakening and compromising of the integrity of the materials. Several experiments were carried out, as part of an extensive and ongoing set, under different conditions that complement the results presented in the previous year. Specifically, inhibitor effects, a wider range of Temperature values, and other conditions, have been explored. As it was done before, mainly the most corrosion resistant combination is being identified.
Control the Corrosion of Magnesium for Implant Application By Hydrothermally Deposited Biodegradable Calcium Phosphate Coating
Authors: Kaabi Falahieh Asl Sara , Nemeth Sandor , Tan Ming Jen
Published: February 2020

The corrosion protection of hydrothermally deposited calcium phosphate coatings on AZ31 magnesium alloy was studied in simulated body fluid (SBF) solution for their potential use as biodegradable implants. The coating mainly consisted of bioresorbable monetite phases. Potentiodynamic and electrochemical impedance spectroscopy (EIS) confirmed that the coatings provided varying levels of corrosion protection depending on the coating deposition temperature. By increasing the deposition temperature and corresponding growth in coating thickness the corrosion current density of the coated magnesium was 10,000 fold lower compared to the bare metal; indicating significantly enhanced corrosion performance of Mg substrate, reaching the corrosion protection requirement for magnesium implant. The barrier effect of Ca-P layers was further supported by the observed magnitude of anodic and cathodic Tafel slopes. Coated samples displayed much larger slopes than bare Mg substrate.

EIS results showed that the size of capacitance loops and the absolute impedance value (|Z|) increases. By increasing the deposition time the corrosion mechanism was changed as a result of partial delamination of top surface of coating. In agreement with the electrochemical experiments, immersion tests in SBF also indicated large improvement in corrosion protection as the mass loss was reduced almost three times when coating was applied as compared to the bare metal.

The uncoated Mg substrate undergoes severe and non-uniform corrosion after 28 days immersion in SBF solution; while, the coated samples displayed intact coating and no obvious pits were observed on the coating surface.

The described biocompatible and biodegradable coatings significantly improved corrosion resistance of Mg substrate and can be promising candidate for biomedical application.

Keywords: Magnesium, Calcium-Phosphate coating, Corrosion resistance, EIS
Protein Interactions with Corroding Metal Surfaces
Authors: Virtanen Sannakaisa
Published: February 2020

Low-corrosion resistant metals, such as Mg or Fe based alloys, have been in the focus of intensive research activities in recent years to be used in biodegradable implants. A general challenge is to tailor the materials and surfaces to achieve the desired and controlled corrosion rate for the targeted applications. A further challenge is to elucidate the influence of the complex biological environment on the corrosion mechanisms of these materials. A vast majority of the studies in this field have been carried out on Mg based materials; far less attention has been given to Fe. A comparison of the behavior of Fe and Mg based alloys in simulated biological environments is on one hand side of practical interest in view of possible biomedical applications of these materials. Moreover, from mechanistic point of view, a direct comparison may aid in elucidating mechanisms of interactions between the constituents of the biological environment and the corroding metal surfaces in more detail. In the present study, we are investigating the influence of proteins on the corrosion behavior of Mg and Fe by electrochemical and surface analytical techniques. Proteins in solution can have multiple effects on corrosion reactions: on one hand side, protein adsorption layers can block electrochemically active surface sites and therefore slow down corrosion. Protein adsorption will be influenced by the surface chemistry of the metals (e.g., wettability, type of oxides/hydroxides formed on the surface, and the resulting surface charges) - therefore different interactions may be expected for Mg and Fe. On the other side, complexation of metal cations can take place by proteins (and amino acids), thereby reducing the free cation concentration and possibly accelerating corrosion. Also this effect depends on the nature of the metal cations; for Fe and Mg dissolution products different strength of interactions can be expected. Electrochemical studies indeed indicate very different interactions of proteins (bovine serum albumin, BSA) on Mg as compared with Fe.  For Mg, inhibition of corrosion in presence of albumin in solution can be observed for short-term experiments. For Fe, a slight increase of corrosion by addition of albumin in solution takes place. In general, the influence of BSA on the corrosion behaviour of Mg is much stronger than that observed for Fe. Surface analytical studies (XPS and ToF-SIMS) demonstrate stronger adsorption of albumin on Mg than on Fe. Moreover, protein adsorption on Mg and Fe varies for different proteins (for instance: albumin vs. lysozyme). Possible mechanisms and critical factors of protein interactions with corroding Fe and Mg surfaces will be discussed.
(Invited) Design Against Hydrogen and Corrosion By Combining Multiscale Modeling and Surface-Sensitive Experiments
Authors: Yildiz Bilge
Published: February 2020

Formation of stable native films that passivate corrosion (i.e. reduce the metal corrosion rate) is essential for the usability of the metal in a given environment. The passive films also serve as a barrier to hydrogen penetration into the metal that causes embrittlement and fracture. Corrosion is a very costly problem; impacting many energy systems and broadly the infrastructure. It can be seen as an “old” problem; but an emerging confluence of novel computational and experimental methods presents an exceptional opportunity to uncover and control the microscopic mechanisms governing material corrosion. In this talk, I will present our work combining synchrotron x-ray and scanning probe experiments combined with atomistic and mesoscale modeling, which uncover corrosion and hydrogen related degradation of materials, and which provide guidance on the design of more robust surfaces against corrosion and hydrogen ingress. First, I will present that, by performing atomistic calculations, we were able to quantify the dependence of hydrogen ingress into the metal on the electronic structure of the surface passive films on zirconium alloys, and give design guidelines for alloy compositions that minimize hydrogen ingress through the passive film in general. Second, I will show that by performing synchrotron x-ray photoelectron spectroscopy and atomistic calculations, we were able to quantify the chemical and electronic properties of sulfide films on steels, and develop more accurate and predictive corrosion models by using this information.
Effect of Boron Addition on Oxide Scale Formation of Ni-Base Superalloys
Authors: Nowak Wojciech , Jałowicka Aleksandra , Young David John , Naumenko Dmitry , Quadakkers Willem J.
Published: February 2020

Ni-base superalloys are commonly used as construction materials for high temperature components e.g. in the hottest sections of aero engines and industrial gas turbines due to a combination of excellent creep and high-temperature oxidation resistance at elevated temperature. Apart from major alloying elements such as Cr, Co, Al, Mo, W, Ti, modern Ni-based superalloys contain minor (between 0.01 and 1 at.%) additions of elements such as Hf, Zr or B for obtaining improved mechanical properties, in particular grain boundary strengthening. However, these minor elements also form thermodynamically very stable oxides and can therefore participate in the oxidation process. Whereas several investigations are available on the effect of Hf and Zr additions on the oxidation behaviour of high temperature alloys, hardly any publications deal with studies related to the effect of B additions on oxide formation mechanisms.

In the present investigation the air oxidation behaviour of two commercially available B containing Ni base alloys (Rene80, CM247) was studied at temperatures in the range 850°C to 1050°C. After various exposure times up to 100h the oxidized samples were investigated with a number of analysis methods, including glow discharge optical emission spectroscopy (GD-OES), optical and scanning electron microscopy (SEM combined with EDX/WDX and EBSD) as well as X-Ray diffraction.

B was found to become incorporated into the oxide scale whereby the participation in the oxidation process strongly depended on alloy composition. The oxidation of B resulted in its depletion from the bulk alloy and was found to be dependent on the exposure conditions, being stronger at higher exposure temperatures and longer exposure times. A modelling approach is presented to correlate B incorporation in the surface oxidation process with its depletion in the bulk alloy.
Synchrotron X-Ray Reflectivity Study of Ni-Oxide-Passive-Layer-and-Water Interface and Yttrium-Stabilized-Zirconia-and-Water Interface
Authors: Park Changyong , Kim Jongjin , Bahn Chibum , Hong Hawoong , Kim Taeho , Kim Seung-Hyun , Hou Binyang , Hong Seungbum , Kim Ji-Hyun
Published: February 2020

The hydration and water interaction at Ni-oxide-water interface and yttrium-stabilized-zirconia (YSZ)-water interface, respectively, have been investigated with synchrotron X-ray reflectivity. For the nickel-oxide-water interface, a thin passive oxide layer was grown on a single crystal Ni(110) substrate in ultra-high vacuum chamber by blowing in pure O2 gas at room temperature after several cycles of sputtering-and-annealing treatment. The high-resolution specular X-ray reflectivity from the passive oxide layer as grown on the single crystal metal substrate was measured in He environment at room temperature to characterize the thin film thickness and the atomic correlations within the oxide thin film. The detailed interfacial structure and the substrate relaxation with a subatomic resolution could be derived based on the measured X-ray reflectivity in terms of the laterally averaged electron density profile in surface normal direction. The virgin passive oxide layer then exposed to pure water, the effect of hydration was observed with the subsequent reflectivity measurement at the same diffractometer geometry. The resultant X-ray reflectivity data showed drastic changes from the original reflectivity data, which indicates a substantial influence of water interaction on the surface termination of the passive layer. On the other hand, single crystal YSZ-water interfaces were studied as representing the most stable ZrO2 phase and water interface system. The three major crystallographic orientations, (111), (110), and (100), were measured and analyzed for the interfacial hydration structures. The studies eventually aim at fundamental understanding of the water interaction on passive oxide layer of metal alloy surface in nuclear power plant environment. Before directly approaching to the simulated reaction in hot pressurized water, the current study provides the reference data to be compared to.
3-Mercapto-1-Propanesulfonate for Cu Electrodeposition Studied By in Situ Shell-Isolated Nanoparticle-Enhanced Raman Spectroscopy (SHINERS)
Authors: Schmitt Kevin Gary , Schmidt Ralf , von Horsten Frank , Vazhenin Grigory , Gewirth Andrew A.
Published: February 2020

Damascene processing of copper interconnects for integrated circuits requires void-free filling of high aspect ratio trenches and vias.  A combination of organic additives is commonly used to achieve bottom-up or superfilling of these features by electrochemical plating.  To better understand the surface interactions of brightening agents, 3-mercapto-1-propanesulfonate (MPS) was studied by in situ shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS).  The influence of each functional group was discerned by individually testing butanethiol and butanesulfonate as model compounds.  In an acidic solution of copper sulfate, MPS coadsorbs with sulfate.  Butanethiol displays similar adsorption behavior, but butanesulfonate demonstrates no Raman bands attributed to surface adsorption.  This strongly suggests that the sulfonate moiety does not interact significantly with the Cu substrate, and MPS adsorption occurs through the thiol linkage.  When chloride is added, sulfate is displaced and both MPS and butanethiol coadsorb with the halide.  However, the Cu-Cl stretching vibration is weaker in the presence of these additives than it is with Cl- alone.  In addition to spectroelectrochemical experiments, Cu deposition processes with these additives were also monitored by electrochemical quartz crystal microbalance measurements.  Butanethiol is more resistant than MPS to both Cu deposition and stripping, which confirms that the sulfonate group plays an important role in facilitating Cu deposition.
Theory of Co-Adsorption and Its Application to Copper Superfilling
Authors: Liske Romy , Krause Robert , Uhlig Benjamin , Gerlich Lukas , Bott Sascha , Wislicenus Marcus , Preusse Axel
Published: February 2020

The advanced scaling in microelectronic devices requires filling of smaller and smaller copper lines without the introduction of voids and defects. Electrochemical deposition is the process of choice as it ensures a bottom-up, void-free copper growth, so-called superfilling. The present work focuses on the mechanism of superfilling based on additive co-adsorption principles. These principles describe the formation of a complex and reversible adsorption layer of two interacting surface active substances [1]. While positive interaction causes enhanced adsorption and increased surface coverage, negative interaction results in inhibited adsorption and lower surface coverage (Figure 1). The co-adsorption theory is adopted to explain the functioning of plating additives which is presumed to be the key for superfilling. Electrochemical measurements and partial fill experiments under production-like conditions are carried out to study the effects of bath additives in sub-100 nm structures. It is shown that superfilling is a result of the synergetic adsorption behavior of two organic additives, accelerator and suppressor, and a balancing between additive accumulation and copper deposition rate. During copper deposition both additives accelerator and suppressor accumulate near the growing surface. Due to diffusion limitations inside narrow features, a higher additive concentration evolves compared to blank surface areas. If the deposition proceeds at a high rate, the different additive concentrations inside and outside small features can be used to achieve superfilling (Figure 2).

References

[1]        B. B. Damaskin, V. A. Safonov, O. A. Baturina, and N. V. Safonov, J. Electroanal. Chem., 550–551, 3 (2003).

Figure 1
Using Graphene As a Conducting Layer and Barrier Layer for High Aspect Ratio through Silicon Via Filling
Authors: Zeng Wei-Yang , Chang Shih-Cheng , Dow Wei-Ping
Published: February 2020

Traditional process for TSV fabrication is a dry process that includes the following step: (1) formation of vias by reactive ion etching; (2) formation of a SiO2 isolation liner; (3) deposition of a TiN barrier layer and a copper seed layer; (4) via fill with copper electrodepositing. Herein, we attempt to use graphene to substitute the TiN barrier layer and the copper seed layer for reducing the traditional process procedure.

Graphene materials, including single layer and multi-layer graphene platelet, have recently drawn extensive attention due to their outstanding electrical and thermal properties. Reduction of graphene oxide (GO) is a method to prepare the graphene film. Since GO has a large amount of oxygen functional groups, it can be well dispersed in several solvents and enable it to be coated on a substrate by a chemical grafting method using a wet process.

In TSV technology, the thermo-mechanical fatigue may lead to failure in the TSV interconnects   because the coefficient of thermal expansion (CTE) of copper is much higher than that of silicon. The packaging materials with different CTEs will induce large stresses at interfaces. To overcome this problem, we choose graphene sheets to substitute the copper seed layer since the CTE of graphene is closer to silicon than copper. In our research, we reduce the procedure of TSV fabrication using a wet process to simultaneously substitute barrier and seed layer with graphene, and to replace filled copper with filled nickel-tungsten alloy in high aspect ratio TSV. This replacement can result in lower fabrication cost compared with the traditional TSV process.
Surfactant-Templated Nanoporous Metal Films and Powders
Authors: Robinson David B. , Cappillino Patrick J. , Jones Christopher G. , Hekmaty Michelle A. , Kent Michael S. , Jacobs Benjamin W. , Hjelm Rex , Parent Lucas R. , Arslan Ilke
Published: February 2020

At sufficiently high concentrations, many surfactants can direct electrodeposited or chemically reduced metals to form nanoporous structures.  The surfactants can be small molecules, block copolymers, or polymers with functional endgroups.   Under some conditions, the pores exhibit uniform, tunable sizes and long-range ordering. We will present a brief overview of demonstrations of these phenomena from the literature, and then focus on our own efforts to produce and characterize various forms of nanoporous palladium, a material of interest for energy storage, hydrogen storage, gas separation and sensing, and catalysis applications.

We have used liquid-cell transmission electron microscopy and small-angle neutron scattering to study the mechanisms of particle growth in the presence of surfactants.  Our results suggest that Pd nanoparticles form and sinter around micelles present in the aqueous phase.  Changing the size of the surfactant molecules affects the size of these micelles, and ultimately determines the pore dimensions. Careful control of surfactant self-assembly and particle growth conditions is required to obtain long-range order.  However, porosity that is more disordered, but still of quite uniform size distribution, can be obtained under much more relaxed conditions, and lower surfactant concentrations.  We believe that interactions between the surfactants and the metal surfaces are more influential in these cases.  The flexible range of conditions under which surfactants are able to induce nanoporosity suggests that this technology could prove to be a valuable synthetic method for energy materials with high power densities, as well as chemical engineering materials with high surface reaction rates.

Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. The Lujan Neutron Scattering Center at LANSCE is funded by the DOE Office of Basic Energy Sciences and Los Alamos National Laboratory under DOE Contract DE-AC52-06NA25396.  The work was funded in part by Sandia’s Laboratory-Directed Research and Development program.
Template-Morphology Dependent Deposition of Ferromagnetic Metals
Authors: Rumpf Klemens , Granitzer Petra , Poelt Peter , Michor Herwig
Published: February 2020

Porous silicon templates with different morphologies have been fabricated offering a self-organized pore-arrangement. The morphology has been varied in a broad range with pore-diameters between 25 and 100 nm but also especially with respect to the roughness of the pore-walls. These templates have been filled with diverse ferromagnetic metals and alloys by electrodeposition. The aim of this work is to fabricate self-organized three dimensional arrays of magnetic nanostructures (wires, particles) with distinct magnetic characteristics within a non-magnetic mattrix. The magnetic properties strongly depend on the shape and size of the deposited nanostructures, their mutual arrangement within the pores as well as on the morphology of the template. Also the texture of the pore-surface plays a key role concerning magnetic coupling between adjacent pores. Furthermore the kind of metal is of importance, whereat for each metal the deposition parameters have to be adjusted individually. The deposition process has been elucidated with respect to the morphology of the template, especially the dendritic pore-growth and the resulting structure of the deposits. The nucleation of the metal deposition starts at surface asperities and the growth of the nanostructures can be influenced by using pulsed electrodeposition and also by the electrolyte. A study of the dependence of the metal deposition on the morphology and the resulting adjustability of the magnetic properties of the 3-dimensional nanostructure array will be presented.
Effect of Plating Additives on Microstructure and Properties of Electrodeposited Ni-Fe Alloy Thin Film
Authors: Hung Mao-Chun , Dow Wei-Ping
Published: February 2020

With the evolving technology, the frame mounted design of electronic components has increasingly become high-density, which leads to the electronic elements that are inevitably vulnerable to electromagnetic interference and then affect other electronic products’ functions. The solution is to use well conductive material that operates the shielding process. The material includes metals and conductive polymers which are common sources of the protective materials in dealing with the main conductive surface. Although this masking method has been widely recognized, several problems are still observed in practice, including the vulnerability to scaling, abrasion, corrosion and process load.

In this study, we adopt Fe-Ni alloy film as the shielding material and manufacture it by  electroplating. We intend to explore the effectiveness of changing the plating bath composition, plating parameter and plating additives on structural strength and magnetic properties of the Fe-Ni alloy film. Different proportions of nickel and iron ion concentration and content of H3BO3 cause different proportions of electrodeposited elements in the film. And the higher content of nickel ion will have higher permeability. In magnetic electroplating, plating additives play an important role. The findings suggest that various additives lead to different crystalline orientations, grain sizes, surface roughness. A strong correlation is also shown between the observed structural changes and the changes in the magnetic properties, such as permeability. Additionally, anti-corrosion is a significant issue. We can improve the corrosion problem by doping little element such as Boron in the film, obtain the corrosion potential and corrosion current by Tafel analysis. The ultimate goal of the study is to meet the requirements of electronic industry in manufacturing high permeability and optimum corrosion resistance for shielding material Fe-Ni alloy film.
Self-Terminated Electrodeposition Reactions
Authors: Moffat Thomas , Liu Yihua , Ahn Sang Hyun , Wang Rongyue , Gokcen Dincer , Hangarter Carlos , Bertocci Ugo
Published: February 2020

In a recent publication Pt deposition at negative potentials revealed an unanticipated self-terminating characteristic that enables controlled deposition of Pt monolayer films from a K2PtCl4-NaCl electrolyte. In the case of Pt, the deposition reaction is quenched at potentials just negative of proton reduction by alteration of the double layer structure and adsorption properties induced by a saturated surface coverage of underpotential deposited hydrogen, (Hupd). The surface may be reactivated for Pt deposition by stepping the potential to more positive values where Hupd is oxidized and fresh sites for adsorption of PtCl4
2- become available. Periodic pulsing of the potential enables sequential deposition of additional Pt layers to fabricate films of desired thickness relevant to a range of advanced technologies in manner that is tantamount to wet atomic layer deposition (ALD).  In the presence of iron group metal the Hupd induced suppression is lifted by underpotential deposition of the iron group metal as revealed in voltammetric studies of singular surfaces and thin film deposition studies of the binary Pt100-xNix and Pt100-xCox alloy. Bulk alloy formation is facilitated by ongoing Pt deposition that incorporates the iron group metal in accord with the excess enthalpy of alloy formation. This talk will present an update on the exploration of the generality of self-terminating deposition reaction to other chemical system.
Effect of Oxygen on Working Life of Additives and Improved Design of Anode Bag in Copper Electroplating
Authors: Hsu Chien-Hsing , Hsu Jia-Feng , Yuan Wei-Li
Published: February 2020

The research studied the degrading and consuming phenomena of organic additives caused by oxygen generated by the insoluble anode in the process of copper electroplating. A double-layer anode bag was designed to prevent the additive ions from approaching the anode and getting degraded. Nitrogen bubbles of a particular size were injected into the anode bag gap to help capture dissolved oxygen molecules and merge with tiny oxygen bubbles coming from the anode. Therefore, the total surface area and number of oxygen bubbles were reduced, the oxygen concentration in the merged bubbles was diluted, and the amount of dissolved oxygen in the electrolyte was lowered. The improved design of anode bag with nitrogen purging slowed down the degrading rate and elongated the working life of the additives, and thereby cut down the production cost. In addition, a recycle system was designed to remove oxygen from nitrogen for reuse of nitrogen.
Effect of Tin Oxide Additive on the Suppression of Dendrite Growth of Zinc Electrodeposits
Authors: Kim Hong-Ik , Shin Heon-Cheol
Published: February 2020

Unlike the market acceptance of Zn-air primary battery, the Zn-air secondary battery is not yet commercialized, mainly due to its poor cycling stability. Although a number of issues have been raised as possible reasons for its low electrical rechargeability, the dendrite growth of Zn during charging process might be most critical because it leads to short circuits and thereby catastrophic failure. Many inorganic additives have been reported for the suppression of the dendritic growth of Zn electrodeposits. For example, it is known that a small amount of Pb ions in an alkaline solution effectively suppresses the Zn dendritic growth. Nevertheless, the environmental issues of Pb-containing additive drive the researchers to search for its alternatives.

Sn is cost effective as well as environmentally friendly. Since it has higher reduction potential than Zn, it might be co-deposited with Zn to possibly change the growth habit of Zn dendrite. In fact, it has been reported that Sn ions affected the Zn deposition on a Zn single crystal at the very low Sn content, implying that Sn can be a possible option to toxic and expensive additives. In this work, we report that SnO additive significantly changes the morphology of Zn electrodeposits and suppresses quite well its dendritic growth. From the cyclic voltammograms at different SnO contents, it is proved that a few milli-moles of Sn ions in the electrolyte have a strong effect on the Sn deposition process. Moreover, the microscopic observation reveals that the non-uniform and dendritic growth of Zn electrodeposits is considerably suppressed at high content of SnO additive. From the depth profiling of the composition of Zn electrodeposit, it is confirmed that Sn is co-deposited with Zn during the course of deposition process, strongly indicating that the incorporated Sn interferes the dendritic growth of Zn. However, the addition of excess SnO resulted in a rough surface and crumbling porous particles containing large amount of Sn phase. 

In this presentation, an optimal SnO content required for the creation of dense Zn electrodeposits will be highlighted. Moreover, the possible mechanism of dendrite growth suppression by Sn ions will be further discussed.
Understanding Capacitive Deionization Performance By Comparing Its Electrical Response with an Electrochemical Supercapacitor
Authors: Garcia - Quismondo Enrique , Santos Cleis , Palma Jesús , Anderson Marc Arlen
Published: February 2020

Capacitive deionization (CDI) is an electrochemical water treatment process that allows one to purify saline water by removing ionic species while storing energy simultaneously. The key to CDI is the adsorption of charged particles (ions) in the electrical double layer (EDL) of an electrode upon polarization by a direct current (DC) power source, the same as charging an electrochemical supercapacitor [1][2]. However, there are some differentiating aspects between CDI and supercapacitors that must be considered before this technology can be commercially competitive [3]. 

When a supercapacitor is charged, energy used is influenced by different parameters such as the current intensity, the electrode capacitance, and also by the current intensity of the previous step (discharge). If the capacitor operates under ideal conditions (i.e, high conductor electrolyte, low resistance connections), the influence of these parameters is practically negligible. However, if the system works under non-ideal conditions (greater electrolyte resistance) as in a CDI system, the influence of these parameters in subsequent stages may be relevant when the current intensity during charging is different than that used in discharge. 

Thus, a better understanding of the operational problems arising from the use of Supercapacitors is significantly important to aid their application as CDI in real-world devices including desalination, municipal drinking water, wastewater treatment and water-reuse projects [4]. 

In this work, a 310 Farads – 2.5 Volts supercapacitor cell and a CDI stack (70 Farads – 1.5 Volts) are tested under new operational cycling modes based on successively apply discharge rates with the same charge intensity, and similarly different charging rates over constant discharge intensity [5]. This approach allow to analyses comparatively the impact of applying charge and discharge at different rates on electrical performance (capacitance, resistance and round-trip energy efficiencies) of both technologies; supercapacitors and CDI. 

References
 

[1] P.M. Biesheuvel, J. Colloid Interface Sci. 2009,332, 258-264. 

[2] P.M. Biesheuvel, B. van Limpt, A. van der Wal, J. Phys. Chem. C
2009, 113, 5636-5640. 

[3] M.A. Anderson, A.L. Cudero, J. Palma, Electrochimica Acta
2010, 55, 3845-3856. 

[4] E. García-Quismondo, C. Santos, Jesús Palma, M. A. Anderson, Desalination and Water Treatment
2014, DOI: 10.1080/19443994.2014.984929. Accepted

[5] E. García-Quismondo, R. Gómez, F. Vaquero, A. López Cudero, J. Palma, M.A. Anderson,, Phys. Chem. Chem. Phys.
2013, 15 (20), 7648-7656.
Improving Electrosorption Performance in Membrane Assisted Capacitive Deionization Cells Using Asymmetric Electrodes Configuration
Authors: Omosebi Ayokunle , Gao Xin , Landon James , Liu Kunlei
Published: February 2020

Capacitive deionization (CDI) is an emerging salt treatment technology that functions by concentrating ionized salt into porous electrodes with the aid of an applied electric field. Unlike some de-salting technologies like distillation or reverse osmosis that separate water from salt content with the aid of added heat or pressure, CDI electrostatically targets the salt content instead, and it is particularly attractive for the treatment of mid (brackish water) to low (tap water) concentration salt streams [1]. In addition, CDI offers the possibility of energy recovery in the convenient form of electricity which can be used to directly power subsequent CDI units, or other auxiliary devices. Membrane-assisted capacitive deionization (MCDI) is an improvement to conventional CDI whereby ion-exchange membranes (IEMs) are placed next to the porous carbon electrodes to increase desalination performance by mitigating losses that result from converting electronic to ionic charge at the electrode-electrolyte double layer.

During MCDI operation, electrode polarization results in the attraction of counter- ions (opposite in polarity to the charged surface), while co-ions (similar in polarity to the charged surface) are repelled away from the polarized surface [2]. The membranes used for the operation hinder the repulsion of co-ions back into the bulk, leading to an increased flux of counter-ions to balance the co-ions contained in the macropore space resulting in typically higher charge efficiencies over the CDI only system. In a departure from the traditional architecture which utilizes the same electrodes to form both the anode and cathode, MCDI systems can instead be asymmetrically assembled with ion-specific electrodes to increase specific charge excesses, and whereby any such specificity can be quantified via potential of zero charge (PZC) measurements.

In order to demonstrate benefits to deionization performance, we will present the electrosorption performance and charging characteristics of MCDI cells configured with pristine and nitric acid-treated Zorflex activated carbon electrodes with PZCs of -0.2 and 0.2 V vs SCE, respectively, based on differential capacitance measurements. Results from the asymmetric configuration will be compared to those from pristine anode-pristine cathode configurations to quantify the extent of variation in performance.

Acknowledgements

The authors are grateful to the U.S. - China Clean Energy Research Center, U.S. Department of Energy for project funding (No. DE-PI0000017), and thankful for the support of the State of Wyoming Advanced Conversion Technologies Task Force for their support.

References

[1]        Y. Oren, Desalination 228 (2008) 10.

[2]        E. Avraham, Y. Bouhadana, A. Soffer, D. Aurbach, J. Electrochem. Soc. 156 (2009) P95.