bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phthalocyanine Based Anti-Corrosive Materials
Authors: Gokceoren Argun T , Arsalanoglu Yasin , Kaplan Ekrem 
Published: February 2020

Nanofibers possess exclusive physical, chemical, and electronic properties. Although different methods are known [1-2], electrospinning has been used with an increasing impact because of the ease of proceeding and the use of a wide range of polymeric materials [3–4] in the production of nanofibers. This electrostatic technique consists by the propulsion of a polymer solution trough an electrostatic field created by a high voltage applied syringe and an oppositely charged collector where the fibrins are formed. The applied electrical field, the collector distance, and the assets of the polymer solution had an immense effect on physical and morphological properties of the fiber such as the diameter, the surface area per unit mass and the pore size [5].
Because of the thermal, chemical and optical stability and the formation of an aligned crystalline film phthalocyanine derivatives have found applications as photovoltaic cells, solar cells, sensor electrodes, drug release systems, gas detectors and electroactive devices [6-9].
In this work, Metal free phthalocyanine grafted polypyrrole and cobalt metallated phthalocyanine grafted polypyrrole nanofibers were successfully collected onto Staineless Steel SAE 1020 (UNS G10200) by means of electrospinning technique. The anti-corrosion performance of the final system has been evaluated in 3 wt.% NaCl solution by means of Electrochemical Impedance Spectroscopy (EIS) and Tafel measurements. Different methods were used to characterize the obtained fibers. Fourier-transform infrared spectroscopy, Scanning electron microscope and polarized optical microscope were used for their morphological characterization, while electrical behaviors of the nanofibers were characterized by direct current and electrochemical impedance spectroscopy measurements.
[1] Feng L., Li S., Li H., Zhai J., Song Y., Jiang L. Angew Chem Int Ed 2002; 41; 1221–1223.
[2] Ma P.X., Zhang R. J Biomed Mat Res 1999; 46; 60–72.
[3] Menon V. P., Lei, J., Martin, C. R. Chem Mater 1996; 8; 2382-86.
[4] Joo J., Park K.T., Kim B.H., Kim M.S., Lee S. Y., Jeong C. K., Lee J. K., Park D. H., Yi W. K., Lee S. H., Ryu, K. S. Synth Met 2003; 135; 7-13.
[5] Chronakis I.S., Grapenson S., Jakob A. Polymer 2006; 47; 1597–1603.
[6] Li Y., Lu P., Yan X., Jin L., Peng Z. RSC Adv 2013; 3; 545-558.
[7] Lu H.-L., Syu W.-J., Nishiyama N., Kataoka K., Lai P.-S. Journal of Controlled Release 2011;155;458–464.
[8] Jeong S.I., Jun I.D., Choi M.J., Nho Y.C., Lee Y.M., Shin H. Macromol Biosc 2008;8;627–637.
[9] Mugadza T., Nyokong T. Synthetic Metals 2010;160; 2089–2098.
Electrochemical Investigation of the Corrosion Behavior and Galvanic Compatibility Between Microchannel Tubes and Fins of an Aluminum Automotive Condenser
Authors: Pech-Canul Maximo A. , Echeverría Marbella , Pech-Canul Martin I. , Aguilar-Cordero Julio C. , Gorocica-Diaz Jorge A. , Arana-Guillén René , Puch-Bleis José 
Published: February 2020

The condenser of air-conditioning unit for automotive application is an aluminum heat exchanger with three main components: the headers, microchannel tubes and fins. It is normally installed in the neighborhood of the front grill, so it is subjected to external corrosion. Of main concern is the possibility of tube perforation, leading to coolant leaking. One way to improve the corrosion resistance of the condenser is to protect the outside of the microchannel tubes with a sprayed zinc coating. The standard test for corrosion of automotive heat exchangers is saltwater acetic acid test (SWAAT) which is intended to reproduce lifetime performance. With the aim of satisfying recent demands in the industry for higher SWAAT performance, a condenser prototype was developed in this study using flat tubes made with a 1000 series alloy spray-coated with zinc and fins made with 3003 series alloy with a double clad of 4343 alloy. The condenser prototype was brazed in a controlled atmosphere industrial furnace, using the Nocolok® flux brazing process. External corrosion was simulated by immersion, in SWAAT solution, of small samples cut from the tube/fin panel, taking care to seal the ends of the tubes with epoxy resin. Results of potentiodynamic polarization and electrochemical impedance spectroscopy were compared to those for individual components (uncouple tube and fin) and indicated that the electrochemical behavior is dominated by the fins. The pitting corrosion resistance of the condenser is afforded by the zinc diffusion layer on the tubes and this effect was investigated with cross-sectional corrosion potential profiles and potentiodynamic determination of the pitting potential. Galvanic compatibility between the tube and fins was evaluated with zero resistance ammetry (ZRA) and showed that there is an evolution in galvanic corrosion as zinc in the diffusion layer gets depleted. Furthermore, the localized corrosion behavior at the tube-fin joint was investigated with scanning electrochemical microscopy (SECM) and scanning vibrating electrode (SVET).
Multifunction Nanostructured Coatings
Authors: Ferreira Mario G. S. , Tedim Joao , Zheludkevich Mikhail L. 
Published: February 2020

The active corrosion protection of metallic substrates can be achieved by addition of corrosion inhibitors to protective coatings. However, direct mixing of an inhibitor with coating formulations can lead to important drawbacks decreasing barrier properties of the coating and diminishing activity of the inhibitor. Also, soluble inhibitors can cause phenomena like osmotic blistering or be leached out spontaneously to the environment, which limits long-term performance and is environmentally pernicious. To overcome this problem and have controlled release of inhibitor different strategies of inhibitors storage in nanocontainers have been developed in order to produce smart self-healing coatings.
In this work novel protective nanostructured coatings with self-healing ability are presented. This effect is obtained on the basis of nanocontainers that release entrapped corrosion inhibitors in response to local pH changes or presence of corrosive species. The development of new nanocontainers for organic and inorganic corrosion inhibitors achieved is described, especially the most promising from industrial point of view, based on Layered Double Hydroxides (LDH). The combination of different of these nanocontainers in the same coating system has proved to be effective to accomplish further functions as antifouling and sensing.
Corrosion Effects of Electrolytic Biocomposites Coated Magnesium on Endolithial Cell Viability
Authors: Yen Shiow Kang , Lin Ruei Cheng , Wang Ming Jia 
Published: February 2020

Though the degradable magnesium alloy used to construct an absorbable stent could be another candidate, its poor corrosion resistance is relatively a serious impediment against wider applications of magnesium alloy[1]. In this study, the coatings of zirconia (ZrO2) bottom layer and calcium phosphate (CaP) top layer are carried out on pure magnesium specimens by electrolytic deposition and subsequent annealing, leading to the corrosion current density reduced from 13.3 to 3.86 μA/cm2 derived by potentiodynamic polarization tests in artificial blood plasma at 37 °C. Furthermore, calcium phosphate (CaP), gelatin (Gel) and heparin (Hep) are co-deposited on post CaP/ZrO2 coated specimens in order to fabricate the heparin sustaining release system for promoting the hemocompatibility of magnesium. Heparin loaded composite coatings are analyzed by X-Ray diffractometry (XRD), field emission scanning electron microscope (FESEM), focused ion beam (FIB) system, toluidine blue colorimetric assay, UV-visible spectrometer, and indirect endothelial cell viability tests. The drug content increases from 243.56±55.18 μg/cm2 for single layer (CaP-Hep) to 484.19±19.26 μg/cm2 for multilayer (CaP-Gel-Hep/CaP-Hep/CaP/ZrO2) and the sustaining release of the latter lasting for more than 28 days compared with that of the former for 1 day in PBS solution. The cell viability, related to Mg2+ ions in medium extracts which are still toxic to endothelial cells at high concentrations, is 63 % for the uncoated, 97 % for the ZrO2 coated, and 110 % for the CaP/ZrO2 and CaP-Gel-Hep/CaP-Hep/CaP/ZrO2 coated specimens compared with 100 % for the negative control. All results indicate that ZrO2 coated, CaP/ZrO2 coated, and CaP-Gel-Hep/CaP-Hep/CaP/ZrO2coated magnesium specimens are potential for biodegradable cardiovascular stents.
Acknowlegement
The authors are grateful for the support of this research by the National Science Council,Republic of China (Taiwan) under contract No. NSC 102-2221-E-005-027-MY3.
[1]M.J. Wang, C.F. Li, S.K. Yen, Electrolytic MgO/ZrO2 duplex-layer coating on AZ91D magnesium alloy for corrosion resistance, Corrosion Science, 76 (2013) 142-153.
Gold/ Polypyrrole Multilayer Electrode for Biochip Applications
Authors: Ofek Almog Rakefet , Sverdlov Yelena , Vernick Sefi , Shacham-Diamand Yosi 
Published: February 2020

Novel gold/ polypyrrole/ gold electrodes for biochip applications are presented. The electrodes demonstrated better conductivity than polypyrrole electrodes and better sensitivity than conventional gold electrodes. We describe the device fabrication and the electrical properties of the electrodes. Polypyrrole was deposited by electrochemical polymerization, and a thin top gold layer was electro-deposited on the Polypyrrole.
A study of the nucleation and growth of the top gold using high resolution scanning electron microscope is presented. Under stagnant conditions a significant electro-crystallization was observed. Electrochemical characterization essential for future bio-sensing application was demonstrated. The electrochemical behavior of the metal/Ppy/metal electrodes was tested by CV and impedance spectroscopy. The novel electrode system was tested for their application as whole cell biosensors using substrate - enzyme interaction by product electrochemical activity. We studied the response of the new electrode in biological solutions (PBS).
We found that depositing Ppy on thin metal seed layer dramatically increases the measured current of the electrodes, as compared to Au electrode. This effect was also demonstrated by CV measurements as well as in amperometric detection of alkaline-phosphatase enzymatic activity using biological chips. This high current produces noise that interferes with the proper operation. However, when sufficient metal is electrodeposited on the Ppy, the behavior of the electrode becomes similar to that of a metal electrode, as demonstrated by CV and by amperometric detection of enzymatic activity. The CV curve has the same characteristics as that of the planar gold electrode, with a considerably higher current peak (Ip).
The modified Au/Ppy/Au electrode yielded an improved signal, compared with that from a flat gold electrode. The electrodeposition of Ppy followed by Au, on the surface of the biochip’s Au seed layer, affected the electrocrystallization of the Au particles on the Ppy (Fig 1) resulting in a high surface area. This electrode can serve as a highly sensitive, high surface area and flexible sensor for biological species.

Figure 1
Study on Thermal Stability of Ag-Coated Cu Powders Fabricated By Electrochemical Methods
Authors: Seo Nali , Zhuo Kai , Park Yu-Seon , Park Jeong-Hwan , Roh Yung-Seok , Chung Chan-Hwa 
Published: February 2020

The conductive paste market is growing with many uses and development in solar cells, touch panels, and other display devices. Those conductive pastes contain the Ag powders as a metal filler to maintain its high electrical conductivity. Recently, as the price and consumption of Ag has been precipitously increased, there are many efforts to use alternative materials.
One of the ways to reduce the paste cost is adoption of core-shell structured metal fillers with putting the inexpensive Cu in the core. By coating the Ag on Cu powders, the low electrical resistance has been maintained even at higher temperatures in air. The key technique in this process is the way how to achieve uniform Ag coating on Cu, which prevents the Cu powders from oxidation and sustains its conductivity.
In our work, galvanic displacement reaction by being based on difference of potential and electroless plating method supplied the electrons from reducing agent are used to coat Ag on Cu powder. The Ag has been formed on Cu powders using electrochemical method that coats uniform metal thickness on material surfaces using those electrochemical methods.
We report Ag shell which has been coated various contents (silver 15wt.%, 30wt.%, 40wt.%) and analyze thermal stability of the powders using FE-SEM (Field Emission Scanning Electron Microscope, JSM-7000F, JEOL, Japan), EDS (Energy Dispersive Spectroscopy, EDAX, U.S.A.), ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometer, Optima-4300 DV, PerkinElmer, U.S.A.), XRD (X-ray Diffraction, D8 ADVANCE, Bruker corporation, Germany), and CP (Cross-section Polishing, IB-09020CP, JEOL, Japan).

Keywords: Core-shell, Silver-coated copper, Galvanic displacement reaction, Electroless plating method, Thermal stability

Figure 1
Citrate Effect on Reaction Kinetics of Pt Deposition on Pd(hkl) Via Surface Limited Redox Replacement of Cu UPD Monolayer
Authors: Brankovic Stanko , Yuan Qiuyi , Shao Minhua 
Published: February 2020

The effect of citrate ions in reaction solution on reaction kinetics of Pt deposition on Pd via SLRR of Cu UPD monolayer has been studied[i]. Experiments involving both, single crystal Pd and Pd-nanoparticle substrates were performed. The results suggest that citrate has a suppressive role on Pt deposition kinetics which is manifested through the zero order reaction kinetics during red-ox process[ii]. The citrate adsorbed phase on Pd surface has mainly transport hindering role for upcoming Pt ions. The IR data suggest that Pt monolayers produced from citrate containing electrolyte have weaker electrosorption ability for CO than bulk Pt and Pd. This information should be useful in further application of citrates as reactant and additive for Pt deposition via SLRR which can be used to fine tune Pt monolayer reactivity on different substrates[iii]. The reaction kinetics model was developed to analyze our kinetics data where the citrate effect was described as an extra barrier for the Pt ion transport. The model is capable of predicting the reaction rate constants from known concentrations of the citrate and platinum ions in the solution using only two model parameters, X and B3. Both parameters have the real physical meaning which could be directly visualized as the additional diffusion path for Pt ions due to the presence of adsorbed citrate layer on CuUPD/Pd-NP surface. The analytical work could be further applied in design and development of more sophisticated apparatus for Pt-shell Pd-core catalyst synthesis. This aspects will be discuss in the conclusion of the talk.
The authors acknowledge the private funding of this work and the support from NSF Chemistry division under the contract # 0955922.

References:

[i]) S. R. Brankovic, J. X. Wang and R.R. Adzic, Surface Science, 474, L173 (2001).
[ii]D. Gokcen, S.-E. Bae, S.R. Brankovic, Electrochimica Acta,
56, 5545 (2011).
[iii] S. R. Brankovic et al, submitted.
Coatings Based on Conducting Polymers and Functionalized Carbon Nanotubes with Anionic Surfactants Obtained By Electropolymerization
Authors: Branzoi Florina , Branzoi Viorel , Pahom Zoia 
Published: February 2020

Nanocomposite films based on 3,4 ethylen-dioxythiophene, 2-aminophenol with functionalized single-walled carbon nanotubes (SWANTs- polyaminobenzene sulfonic acid - CNT-PABS, SWANTs- with carboxylic acids functionalized - CNT-COOH) and different anionic surfactants as dopants (sodium dioctyl sulfosuccinate - AOT, sodium dodecylbenzenesulfonate - SDBS) were studied. It was fabricated by a simple oxidative electropolimerization method.
All the obtained composites showed improved mechanical integrity, higher electronic and ionic conductivity and exhibited larger electrode specific capacitance than the polymer alone. These nanoporous composite films were grown electrochemically from aqueous solutions such that constituents were deposited simultaneously onto substrate electrode.
The synthetic, morphological and electrical properties of the obtained nanocomposite films were compared. Scanning electron microscopy (SEM) revealed that the composite films consisted of nanoporous networks of SWCNTS (single-walled carbon nanotubes) coated with polymeric film. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) demonstrated that these composite films had similar electrochemical response rates to pure polymeric films but a lower resistance and much improved mechanical integrity. The negatively charged functionalized carbon nanotubes (CNTSF) served as anionic dopant during the electropolymerization to synthesize polymer/CNTSF composite films. The electrochemical and physical properties of the resulting composites were evaluated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and FT-IR spectroscopy techniques.The specific electrochemical capacitance of the composite films is a significantly greater value than that for pure polymer films prepared similarly. Using these composite films doped with anionic surfactants, the modified electrodes with improved properties were obtained.

Figure 1
Electrodeposition of PbO2 on Reticulated Vitreous Carbon for Organic Electrooxidation
Authors: Ruotolo Luis Augusto Martins , Farinos Rosimeire Martins 
Published: February 2020

The problems caused by the growing of the environmental contamination by organics have been calling the attention of researches, authorities, and population in general since their effects have been more present in our lives. Environmental contamination can be avoided by using, in most cases, biological treatments; however, some classes of compounds are refractory to this kind of treatment and require different technologies to oxidize the organic compound.
In this context, the electrochemical technology emerged as an alternative environmentally, technically, and economically viable. Advantages of electrochemical technology are elimination of transport and storage of hazardous chemicals, reduction of the workmanship, and ease to automatization. Despite these advantages, for the effective use of the electrochemical technology for effluent treatment some drawbacks must be overcome, mainly mass transfer limitations resulting of the low concentrations in industrial effluents, which affect the current efficiency and the energy consumption. As an attempt to improve mass transfer, in this work we address the electrochemical oxidation using three-dimensional electrodes of reticulated vitreous carbon (RVC) covered by PbO2film as the electroactive material.
The RVC/PbO2 electrode was prepared in a flow electrochemical reactor. The PbO2 film was electrodeposited on RVC applying different charges by varying the current density and electrolysis time. The porosities (in pores per inch) of the RVC substrates were 45, 60, and 80 ppi. The electrode was characterized by electrochemical techniques and scanning electronic microscopy. The decolorization reaction of the reactive blue 19 dye was used to evaluate the electrocatalytic power of the RVC/PbO2and compared to the flat plate electrode.
The results for the 45 ppi RVC showed that the PbO2electrodeposition was not uniform within RVC due to non-uniform current penetration (Fig. 1 and 2). The best electrodeposit morphology and uniformity was obtained applying low current densities for longer electrolysis time (Fig 1c). Contrary, fast decolorization rate was obtained using the films deposited applying high current density (Fig. 2).
A comparison between the flat plate and RVC/PbO2electrodes in Fig. 3 shows that the three-dimensional electrode was very effect to remove color.
In order to increase the electrode specific surface area, PbO2 films were electrodeposited on RVC with 60 ppi and 80 ppi. After current density optimization, the PbO2 film was successfully deposited on the 60 ppi RVC. On the other hand, an optimum current density cannot be found in order to obtain a uniform deposit on the 80 ppi RVC. Moreover, the low porosity of this electrode and the high hydrophobic nature of RVC led to low surface wettability, thus contributing for the uneven PbO2 film.

Figure 1
Impact of Improvements in Energy Efficiency in Capacitive Deionization Systems
Authors: Landon James , Gao Xin , Omosebi Ayokunle , Liu Kunlei 
Published: February 2020

Capacitive deionization (CDI) is a developing technology for water desalination applications with benefits over current methods such as reverse osmosis (RO) and distillation due to its operation at lower temperatures and pressure. CDI uses small applied potentials (<2.0 V) to selectively separate ions from feed water streams by reversibly adsorbing these ions in the electric double layer of conductive, high surface area, and porous carbon electrodes. This reversible absorption process can be used in a variety of configurations including flow-by, flow-through, and flowable electrode arrangements.1 Classic CDI systems have charge efficiency (equivalent charge of salt adsorbed per electronic charge input) values well below 100% due to parasitic discharge processes and Faradaic reactions.2,3 Therefore, ion-exchange membranes have been added into these systems to increase the effective adsorption capacity of the electrodes and limit the extent of parasitic processes.
Overall, CDI systems are considered to be more efficient than RO membranes for many lower concentration salt streams (<5000 ppm) due to differences in its separation mechanism.4 Shown in Figure 1 is an energy cost comparison of CDI and RO technologies as a function of salt concentration. CDI is shown with energy recovery values of 0, 25, and 50%. As the concentration of NaCl decreases, there is a distinct region where the energy cost of this separation can best RO.
The more recent addition of ion-exchange membranes in a membrane capacitive deionization (MCDI) process can further increase the charge efficiency to over 100% in certain instances and aid in further decreasing energy costs.5 The efficiency of both the CDI and MCDI process make them attractive options for many larger scale applications where energy cost becomes a dominant factor in choosing the water treatment system. In this talk, a comparison between the energy costs of RO and CDI/MCDI will be given. The use of recent surface chemistries to increase the charge efficiency will be shown to decrease the energy cost of CDI/MCDI processes further. Finally, applications will be reviewed where CDI and MCDI can be used as a standalone option as well as interface with existing membrane processes.

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).

References

1. S. Porada, R. Zhao, A. van der Wal, V. Presser and P. M. Biesheuvel, Progress in Materials Science, 58, 1388 (2013).
2. E. Avraham, M. Noked, I. Cohen, A. Soffer and D. Aurbach, Journal of The Electrochemical Society, 158, P168 (2011).
3. X. Gao, A. Omosebi, J. Landon and K. Liu, Journal of The Electrochemical Society, 161, E159 (2014).
4. Y. Oren, Desalination, 228, 10 (2008).
5. A. Omosebi, X. Gao, J. Rentschler, J. Landon and K. Liu, Journal of Colloid and Interface Science (in press).

Figure 1