Enhancement of the Electrochemical Properties of an Open-Pore Graphite Foam with Electrochemically Reduced Graphene Oxide and Alternating Current Dispersed Platinum Particles

[EN] This paper aimed to improve the electrochemical activity of a pitch-derived open-pore graphite foam (GF) by an electrochemical coating of reduced graphene oxide (RGO) and platinum particles without significantly affecting its 3D-structure. RGO was synthesized using cyclic voltammetry (CV) from a 3 g L(-1)GO and 0.1 M LiClO(4)solution. For the electrodeposition of Pt particles, an alternating current method based on electrochemical impedance spectroscopy (EIS) was used. A sinusoidal voltage from a fixed potential Ei was varied following a selected amplitude (Delta E-ac= +/- 0.35 V) in a frequency range of 8 Hz <= f(i)<= 10Hz, wherei= 500. This method proved its efficiency when compared to the traditional CV by obtaining more highly electroactive coatings in less synthesis time. For samples' characterization, physical measures included permeability, pressure drop, and nitrogen adsorption isotherms. The electrochemical characterization was performed by CV. The surface morphology and chemical composition were examined using field emission electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDX), respectively. RGO improved the electron transfer rate constant of GF, and a more homogeneous coating distribution of reduced size Pt particles was obtained.This research was funded by the Spanish Agencia Estatal de Investigación (AEI) and the European Union (FEDER funds) contracts (MAT2016-77742-C2-1-P, MAT2016-77742-C2-2-P). Financial support of Network E3TECH (CTQ2017-90659-REDT) is acknowledged.Fernández Sáez, J.; Bonastre Cano, JA.; Molina, JM.; Cases, F. (2020). Enhancement of the Electrochemical Properties of an Open-Pore Graphite Foam with Electrochemically Reduced Graphene Oxide and Alternating Current Dispersed Platinum Particles. Coatings. 10(6):1-12. https://doi.org/10.3390/coatings10060551S112106Prieto, R., Louis, E., & Molina, J. M. (2012). Fabrication of mesophase pitch-derived open-pore carbon foams by replication processing. Carbon, 50(5), 1904-1912. doi:10.1016/j.carbon.2011.12.041Molina-Jordá, J. M. (2016). Mesophase pitch-derived graphite foams with selective distribution of TiC nanoparticles for catalytic applications. Carbon, 103, 5-8. doi:10.1016/j.carbon.2016.02.051Lai, J., Nsabimana, A., Luque, R., & Xu, G. (2018). 3D Porous Carbonaceous Electrodes for Electrocatalytic Applications. Joule, 2(1), 76-93. doi:10.1016/j.joule.2017.10.005Morozov, S. V., Novoselov, K. S., Katsnelson, M. I., Schedin, F., Elias, D. C., Jaszczak, J. A., & Geim, A. K. (2008). Giant Intrinsic Carrier Mobilities in Graphene and Its Bilayer. Physical Review Letters, 100(1). doi:10.1103/physrevlett.100.016602Singh, V., Joung, D., Zhai, L., Das, S., Khondaker, S. I., & Seal, S. (2011). Graphene based materials: Past, present and future. Progress in Materials Science, 56(8), 1178-1271. doi:10.1016/j.pmatsci.2011.03.003Zhou, M., Wang, Y., Zhai, Y., Zhai, J., Ren, W., Wang, F., & Dong, S. (2009). Controlled Synthesis of Large-Area and Patterned Electrochemically Reduced Graphene Oxide Films. Chemistry - A European Journal, 15(25), 6116-6120. doi:10.1002/chem.200900596Bonanni, A., & Pumera, M. (2012). Electroactivity of graphene oxide on different substrates. RSC Advances, 2(28), 10575. doi:10.1039/c2ra22079bZhong, M., Song, Y., Li, Y., Ma, C., Zhai, X., Shi, J., … Liu, L. (2012). Effect of reduced graphene oxide on the properties of an activated carbon cloth/polyaniline flexible electrode for supercapacitor application. Journal of Power Sources, 217, 6-12. doi:10.1016/j.jpowsour.2012.05.086Yoo, E., Okata, T., Akita, T., Kohyama, M., Nakamura, J., & Honma, I. (2009). Enhanced Electrocatalytic Activity of Pt Subnanoclusters on Graphene Nanosheet Surface. Nano Letters, 9(6), 2255-2259. doi:10.1021/nl900397tKundu, P., Nethravathi, C., Deshpande, P. A., Rajamathi, M., Madras, G., & Ravishankar, N. (2011). Ultrafast Microwave-Assisted Route to Surfactant-Free Ultrafine Pt Nanoparticles on Graphene: Synergistic Co-reduction Mechanism and High Catalytic Activity. Chemistry of Materials, 23(11), 2772-2780. doi:10.1021/cm200329aXin, Y., Liu, J., Zhou, Y., Liu, W., Gao, J., Xie, Y., … Zou, Z. (2011). Preparation and characterization of Pt supported on graphene with enhanced electrocatalytic activity in fuel cell. Journal of Power Sources, 196(3), 1012-1018. doi:10.1016/j.jpowsour.2010.08.051Zhang, Y., Liu, C., Min, Y., Qi, X., & Ben, X. (2013). The simple preparation of graphene/Pt nanoparticles composites and their electrochemical performance. Journal of Materials Science: Materials in Electronics, 24(9), 3244-3248. doi:10.1007/s10854-013-1235-xProducts: Chemically Modified Graphene Oxidehttps://www.nanoinnova.com/product/chemically-modified-g

Electrochemical study on an activated carbon cloth modified by cyclic voltammetry with polypyrrole/anthraquinone sulfonate and reduced graphene oxide as electrode for energy storage

[EN] This work describes a two-step procedure for the electrochemical coating of reduced graphene oxide (RGO) and polypyrrole anthraquinone sulfonate (PPyAQS) onto an activated carbon cloth (ACC) by cyclic voltammetry (CV). The textile samples were characterized by CV, electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge measurements using a sandwich-type (electrode/separator/electrode) cell designed to operate in three or two-electrode configurations. The presence of RGO onto the ACC surface optimized the electrosynthesis of PPyAQS and reinforced the stability of the polymer with the number of charge/discharge cycles. A retention capacity of 90% after 100 charge-discharge cycles together with an energy density of 7.8¿×¿10¿4¿W¿h¿cm¿2 at a power density of 1.8¿×¿10¿3¿W¿cm¿2 were obtained for the ACC/RGO/PPyAQS sample. The analyses by field emission scanning electron microscopy (FESEM) showed the RGO veils-like and PPyAQS glomerular structures covering the ACC-fibers. The Fourier transform infrared spectroscopy (FTIR) analyses not only detected the presence of PPy and AQS, but also, the changes in the molecular structure of PPyAQS, depending on its oxidation state, as consequence of the redox reactions occurred in the charge/discharge processes in the two-electrode cell.The authors wish to acknowledge to Chemviron Carbon who kindly donated the ZORFLEX® activated carbon fabric. The authors wish to thank the Spanish Agencia Estatal de Investigación de Economía (AEI) and European Union (FEDER funds) for the financial support (contract MAT2016-77742-C2-1-P). Tim Vickers is gratefully acknowledged for help with the English revision. Electron Microscopy Service of the UPV (Universitat Politècnica de València) is gratefully acknowledged for help with FESEM characterization.Fernández Sáez, J.; Bonastre Cano, JA.; Molina Puerto, J.; Cases, F. (2018). Electrochemical study on an activated carbon cloth modified by cyclic voltammetry with polypyrrole/anthraquinone sulfonate and reduced graphene oxide as electrode for energy storage. European Polymer Journal. 103:179-186. https://doi.org/10.1016/j.eurpolymj.2018.04.018S17918610

On the behaviour of Atrazine removal from water using fabrics as anodes and Cathodes

[EN] This study examines the degradation of atrazine (ATZ) with Pt-modified textile electrodes using an electrochemical method that is comparatively studied in two electrochemical cell configurations: cells with separated anodic and cathodic compartments (divided configuration); and without any separation (undivided configuration). The influence of the presence of chloride ions was studied. The best results were obtained when an undivided cell was used. The morphology and composition of the dispersed Pt coatings were analyzed using field emission scanning electron microscopy (FESEM) and Energy Dispersive X-Ray Analysis. The FESEM analyses confirmed that the textile surface was effectively modified by the electrocatalytic material. High performance liquid chromatography, gas chromatography mass spectrometry, and spectroscopic methods were used to follow the evolution of major oxidation products. Total organic carbon, chemical oxygen demand, and total nitrogen were used to evaluate the degradation efficiency of treated aqueous solutions. The experimental results obtained indicate that the efficiency of the electrochemical treatment was high with a low energy consumption when using electrodes based on textile materials, such as anodes or as cathodes (in particular, in electrolysis without compartment separation). All these can be produced at very competitive pricesSpanish Agencia Estatal de Investigacion (AEI) and European Union (FEDER funds) are acknowledged for the financial support (contracts MAT 2016-77742-C2-1-P and CTQ 2017-90659-RED). Chemviron Carbon who kindly donated the FlexzorbTM FM10 activated carbon fabrics and Funding for open access charge, CRUE-Universitat Politècnica de València, are acknowledged tooHamous, H.; Khenifi, A.; Orts Maiques, FJ.; Bonastre Cano, JA.; Cases, F. (2022). On the behaviour of Atrazine removal from water using fabrics as anodes and Cathodes. Chemosphere. 291(Part 1):1-8. https://doi.org/10.1016/j.chemosphere.2021.132738S18291Part

Characterization of polypyrrole/phosphotungstate membranes by electrochemical impedance spectroscopy

The aim of this study was to design and prepare multifunctional PPy/PW12O403- membranes useful for the development of smart textile fabrics and wastewaters treatments based on the application of electrochemical techniques. These PPy/PW12O403- membranes have been characterized by means of electrochemical impedance spectroscopy by using electrochemical cells with different configurations based on the use of two-, three-, or four-electrode experiments. The activation energy of the films in the temperature range 35-70 degrees C was 170 meV. It has been demonstrated that after measuring the PPy films in different NaCl solutions, both the rate of ionic exchange and the diffusion processes through the membrane are faster for more concentrated solutions. Ionic exchange and diffusion were very prevented with a large cation as tetramethylammonium. The impedance spectra obtained with metal/polymer/electrolyte configuration show that the electrical conduction developed through coatings in strong acid solution is controlled by finite-length diffusion processes with reflective boundary conditions. At pH 13, the electrical response proceeds through the oxide layer (Fe and Cr oxides) and the steel/electrolyte interface. In this case, the polymeric coating is very porous due to the counter-ion disintegration. The decomposition of the counter-ion was corroborated by means of energy dispersive X-ray and Fourier transform infrared spectroscopy. (C) 2013 Elsevier B.V. All rights reserved.Authors thank to the Spanish Ministerio de Ciencia e Innovacion (contract CTM2011-23583) and Universitat Politecnica de Valencia (Primeros Proyectos de Investigacion (PAID-06-10)) for the financial support. J. Molina is grateful to the Conselleria d'Educacio, Formacio i Ocupacio (Generalitat Valenciana) for the Programa VALi+D Postdoctoral Fellowship.Bonastre Cano, JA.; Molina Puerto, J.; Galvan, JC.; Cases Iborra, FJ. (2014). Characterization of polypyrrole/phosphotungstate membranes by electrochemical impedance spectroscopy. Synthetic Metals. 187:37-45. https://doi.org/10.1016/j.synthmet.2013.10.020S374518

Study of the Reuse of Industrial Wastewater After Electrochemical Treatment of Textile Effluents without External Addition of Chloride

[EN] The interference of human beings in the environment is causing rapid intense environmental damage which is particularly evident in the depletion of natural resources. Research into powerful practical treatments to decolorize and degrade colored textile wastewater is an important challenge nowadays for the textile industry due to environmental considerations, along with the potential water saving. It has been verified, in previous studies, that electrochemical oxidation-reduction treatment with doped SnO2 anodes was effective. In particular, those belonging to a trychromy (mix of three reactive dyes) achieved a significant reduction in Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC), as well as the decolorization of the treated solutions. Subsequently, the next step is to proceed to study and verify that these treated waters can be reused in subsequent dyes and that acceptable values of color equalization in the dyed fabrics can be achieved. The color differences obtained in the dyed fabrics in the four studied reuses are below the threshold of acceptance of color differences in the textile industry, which is one unit. The only electrolyte used was sodium sulphate. Chloride was not added externally in order to avoid as far as possible indirect oxidation. This allows a true test of the electrooxidantion power of the anodes. In these conditions, the Ti/SnO2-Sb-Pt DSA electrode is stable. The degree of mineralization is evaluated by measurements of TOC and COD. These data also allow the Average Oxidation State (AOS) at the end of each electrolysis, as well as information on the efficiency in each case through the Carbon Oxidation State (COS) and Average Current Efficiency (ACE) to be established. High Performance Liquid Chromatography (HPLC) was used to study the decolorization kinetics and the evolution of the generated intermediates. Comparison of the spectra obtained by UV-Visible Spectroscopy allows the decolorization from the initial state to the end of the electrolysis to be monitored.The authors wish to thank the Spanish Agencia Estatal de Investigación (AEI) and European Union (FEDER funds) for the financial support (contract MAT2016-77742-C2-1-P). The authors wish to acknowledge Tim Vickers for help with the English revision and Texcoy S.L. company (Spain) where the dyeing processes were done.Orts Maiques, FJ.; Del Río García, AI.; Molina Puerto, J.; Bonastre Cano, JA.; Cases, F. (2019). Study of the Reuse of Industrial Wastewater After Electrochemical Treatment of Textile Effluents without External Addition of Chloride. International Journal of Electrochemical Science. 14(2):1733-1750. https://doi.org/10.20964/2019.02.27S1733175014

Electrochemical treatment of real textile wastewater: Trichromy Procion HEXL

[EN] The electrochemical treatment of wastewaters from the textile industry is a promising technique for not easily biodegradable compounds. This work is aimed at studying the electrochemical degradation of bifunctional reactive dyes after a real dyeing process. These are: Procion Yellow HELX®, Procion Crimson HELX® and Procion Navy HELX®, which are widely used in dyeing processes of cellulose fibers. Their structure is mainly characterized by the presence of two azo groups as chromophore group and two monochlorotriazinic groups as reactive groups. Electrolyses were carried out under galvanostatic conditions in an undivided electrolytic cell. Ti/SnO2-Sb-Pt and stainless steel electrodes were used as anode and cathode, respectively. In all cases Na2SO4 was used as electrolyte without external addition of chloride. The degree of degradation was evaluated by means of Total Organic Carbon (TOC) and Chemical Oxygen Demand (COD) measurements. The decolourization kinetics and the presence of the intermediates generated due to of the electrochemical treatment were studied by High Performance Liquid Chromatography (HPLC) and these studies were also carried out with UV¿Visible and Fourier Transform Infrared (FTIR) Spectroscopies. In all cases, a decrease in TOC and COD, and a complete decolourization were obtained after the electrochemical treatment. AOS and COS data proved the presence of oxidised intermediates in solution after the electrolyses. These results suggest the possibility of reusing the treated water in several dyeing processes.The authors wish to thank the Spanish Agencia Estatal de Investigacion (AEI) and European Union (FEDER funds) for the financial support (contract MAT2016-77742-C2-1-P). A.I. del Rio is grateful to the Spanish Ministerio de Ciencia y Tecnologia for her FPI fellowship. J. Molina is grateful to the Conselleria d'Educacio, Formacio i Ocupacio (Generalitat Valenciana) for the Programa VALi + D Postdoctoral Fellowship (APOSTD/2013/056). The authors wish to acknowledge to the Texcoy S.L. company (Spain) where the dyeing processes were done and Tim Vickers for help with the English revision.Orts Maiques, FJ.; Del Río García, AI.; Molina Puerto, J.; Bonastre Cano, JA.; Cases, F. (2018). Electrochemical treatment of real textile wastewater: Trichromy Procion HEXL. Journal of Electroanalytical Chemistry. 808:387-394. doi:10.1016/j.jelechem.2017.06.051S38739480

Synthesis of PPy/PW12O403- organic-inorganic hybrid material on polyester yarns and subsequent weaving to obtain conductive fabrics

In this paper, we study the morphological, chemical and electrochemical characteristics of conductive fabrics obtained by weaving conductive yarns of polyester chemically coated with PPy (polypyrrole)/PW12O403-. The weaving process allows us to obtain conductive fabrics with higher dimensions than those traditionally obtained by in-situ chemical oxidation methods. Untwisted yarns and satin fabrics produced the most satisfactory results. The yarns of PES - PPy/PW12O403- as well as the fabric obtained after weaving, were chemically characterized by means of Fourier transform infrared spectroscopy with attenuated total reflection and energy dispersive X-ray. Scanning electron microscopy was employed to observe the morphology of the coating as well as the formation of defects during the weaving process. Electrochemical impedance spectroscopy was employed to measure the conductivity of the fabrics and the conductive nature by means of the phase angle. The process was satisfactory since the coating of polypyrrole was not excessively damaged by the weaving processThis work was supported by the Spanish Ministerio de Ciencia y Tecnologia and European Union Funds (FEDER) (grant number CTM2010-18842-C02-02); and Universidad Politecnica de Valencia (grant number PAID-06-10).Romero, E.; Molina Puerto, J.; Del Río García, AI.; Bonastre Cano, JA.; Cases Iborra, FJ. (2011). Synthesis of PPy/PW12O403- organic-inorganic hybrid material on polyester yarns and subsequent weaving to obtain conductive fabrics. Textile Research Journal. 81(14):1427-1437. doi:10.1177/0040517511407379S142714378114Service, R. F. (2003). TECHNOLOGY: Electronic Textiles Charge Ahead. Science, 301(5635), 909-911. doi:10.1126/science.301.5635.909De Rossi, D. (2007). A logical step. Nature Materials, 6(5), 328-329. doi:10.1038/nmat1892Hamedi, M., Forchheimer, R., & Inganäs, O. (2007). Towards woven logic from organic electronic fibres. Nature Materials, 6(5), 357-362. doi:10.1038/nmat1884Lekpittaya, P., Yanumet, N., Grady, B. P., & O’Rear, E. A. (2004). Resistivity of conductive polymer-coated fabric. Journal of Applied Polymer Science, 92(4), 2629-2636. doi:10.1002/app.20270Kincal, D., Kumar, A., Child, A. D., & Reynolds, J. R. (1998). Conductivity switching in polypyrrole-coated textile fabrics as gas sensors. Synthetic Metals, 92(1), 53-56. doi:10.1016/s0379-6779(98)80022-2Wu, J., Zhou, D., Too, C. O., & Wallace, G. G. (2005). Conducting polymer coated lycra. Synthetic Metals, 155(3), 698-701. doi:10.1016/j.synthmet.2005.08.032Oh, K. W., Park, H. J., & Kim, S. H. (2003). Stretchable conductive fabric for electrotherapy. Journal of Applied Polymer Science, 88(5), 1225-1229. doi:10.1002/app.11783Kim, S. H., Oh, K. W., & Bahk, J. H. (2004). Electrochemically synthesized polypyrrole and Cu-plated nylon/spandex for electrotherapeutic pad electrode. Journal of Applied Polymer Science, 91(6), 4064-4071. doi:10.1002/app.13625Bhat, N. V., Seshadri, D. T., Nate, M. M., & Gore, A. V. (2006). Development of conductive cotton fabrics for heating devices. Journal of Applied Polymer Science, 102(5), 4690-4695. doi:10.1002/app.24708Hakansson, E., Kaynak, A., Lin, T., Nahavandi, S., Jones, T., & Hu, E. (2004). Characterization of conducting polymer coated synthetic fabrics for heat generation. Synthetic Metals, 144(1), 21-28. doi:10.1016/j.synthmet.2004.01.003Boutrois, J. P., Jolly, R., & Pétrescu, C. (1997). Process of polypyrrole deposit on textile. Product characteristics and applications. Synthetic Metals, 85(1-3), 1405-1406. doi:10.1016/s0379-6779(97)80294-9Kuhn, H. H., Child, A. D., & Kimbrell, W. C. (1995). Toward real applications of conductive polymers. Synthetic Metals, 71(1-3), 2139-2142. doi:10.1016/0379-6779(94)03198-fVaresano, A., & Tonin, C. (2008). Improving Electrical Performances of Wool Textiles: Synthesis of Conducting Polypyrrole on the Fiber Surface. Textile Research Journal, 78(12), 1110-1115. doi:10.1177/0040517507077488Najar, S. S., Kaynak, A., & Foitzik, R. C. (2007). Conductive wool yarns by continuous vapour phase polymerization of pyrrole. Synthetic Metals, 157(1), 1-4. doi:10.1016/j.synthmet.2006.11.003Kaynak, A., Najar, S. S., & Foitzik, R. C. (2008). Conducting nylon, cotton and wool yarns by continuous vapor polymerization of pyrrole. Synthetic Metals, 158(1-2), 1-5. doi:10.1016/j.synthmet.2007.10.016Neoh, K. G., Young, T. T., Kang, E. T., & Tan, K. L. (1997). Structural and mechanical degradation of polypyrrole films due to aqueous media and heat treatment and the subsequent redoping characteristics. Journal of Applied Polymer Science, 64(3), 519-526. doi:10.1002/(sici)1097-4628(19970418)64:33.0.co;2-nLin, T., Wang, L., Wang, X., & Kaynak, A. (2005). Polymerising pyrrole on polyester textiles and controlling the conductivity through coating thickness. Thin Solid Films, 479(1-2), 77-82. doi:10.1016/j.tsf.2004.11.146Ferrero, F., Napoli, L., Tonin, C., & Varesano, A. (2006). Pyrrole chemical polymerization on textiles: Kinetics and operating conditions. Journal of Applied Polymer Science, 102(5), 4121-4126. doi:10.1002/app.24149Garg, S., Hurren, C., & Kaynak, A. (2007). Improvement of adhesion of conductive polypyrrole coating on wool and polyester fabrics using atmospheric plasma treatment. Synthetic Metals, 157(1), 41-47. doi:10.1016/j.synthmet.2006.12.004Molina, J., del Río, A. I., Bonastre, J., & Cases, F. (2008). Chemical and electrochemical polymerisation of pyrrole on polyester textiles in presence of phosphotungstic acid. European Polymer Journal, 44(7), 2087-2098. doi:10.1016/j.eurpolymj.2008.04.007Seung Lee, H., & Hong, J. (2000). Chemical synthesis and characterization of polypyrrole coated on porous membranes and its electrochemical stability. Synthetic Metals, 113(1-2), 115-119. doi:10.1016/s0379-6779(00)00193-4Gasana, E., Westbroek, P., Hakuzimana, J., De Clerck, K., Priniotakis, G., Kiekens, P., & Tseles, D. (2006). Electroconductive textile structures through electroless deposition of polypyrrole and copper at polyaramide surfaces. Surface and Coatings Technology, 201(6), 3547-3551. doi:10.1016/j.surfcoat.2006.08.128Dall’Acqua, L., Tonin, C., Varesano, A., Canetti, M., Porzio, W., & Catellani, M. (2006). Vapour phase polymerisation of pyrrole on cellulose-based textile substrates. Synthetic Metals, 156(5-6), 379-386. doi:10.1016/j.synthmet.2005.12.021Dall’Acqua, L., Tonin, C., Peila, R., Ferrero, F., & Catellani, M. (2004). Performances and properties of intrinsic conductive cellulose–polypyrrole textiles. Synthetic Metals, 146(2), 213-221. doi:10.1016/j.synthmet.2004.07.005Gomez-Romero, P. (2001). Hybrid Organic-Inorganic Materials—In Search of Synergic Activity. Advanced Materials, 13(3), 163-174. doi:10.1002/1521-4095(200102)13:33.0.co;2-uCui, Y., Wu, Q., & Mao, J. (2004). Preparation and conductivity of polypyrrole molybdotungstovanadogermanic heteropoly acid hybrid material. Materials Letters, 58(19), 2354-2356. doi:10.1016/j.matlet.2004.02.037KORMALI, P., TRIANTIS, T., DIMOTIKALI, D., HISKIA, A., & PAPACONSTANTINOU, E. (2006). On the photooxidative behavior of TiO2 and PW12O403−: OH radicals versus holes. Applied Catalysis B: Environmental, 68(3-4), 139-146. doi:10.1016/j.apcatb.2006.07.024DEVASSY, B., LEFEBVRE, F., & HALLIGUDI, S. (2005). Zirconia-supported 12-tungstophosphoric acid as a solid catalyst for the synthesis of linear alkyl benzenes. Journal of Catalysis, 231(1), 1-10. doi:10.1016/j.jcat.2004.09.024Zhu, J., Wei, S., Zhang, L., Mao, Y., Ryu, J., Mavinakuli, P., … Guo, Z. (2010). Conductive Polypyrrole/Tungsten Oxide Metacomposites with Negative Permittivity. The Journal of Physical Chemistry C, 114(39), 16335-16342. doi:10.1021/jp1062463Kuhn HH and Child AD Electrically conducting textiles. In: Skotheim TA, Elsenbaumer RL and Reynolds JR (eds) Handbook of conducting polymers . New York: Marcel Dekker, Inc, 1998, pp. 993-1013.Avlyanov, J. K., Kuhn, H. H., Josefowicz, J. Y., & MacDiarmid, A. G. (1997). In-situ deposited thin films of polypyrrole: conformational changes induced by variation of dopant and substrate surface. Synthetic Metals, 84(1-3), 153-154. doi:10.1016/s0379-6779(97)80689-3Vishnuvardhan, T. K., Kulkarni, V. R., Basavaraja, C., & Raghavendra, S. C. (2006). Synthesis, characterization and a.c. conductivity of polypyrrole/Y2O3 composites. Bulletin of Materials Science, 29(1), 77-83. doi:10.1007/bf02709360Feng, W., Zhang, T. R., Liu, Y., Lu, R., Zhao, Y. Y., & Yao, J. N. (2003). Journal of Materials Science, 38(5), 1045-1048. doi:10.1023/a:1022302031156Su, W., & Iroh, J. O. (1999). Electropolymerization of pyrrole on steel substrate in the presence of oxalic acid and amines. Electrochimica Acta, 44(13), 2173-2184. doi:10.1016/s0013-4686(98)00343-0López, J., Parres, F., Rico, I., Molina, J., Bonastre, J., & Cases, F. (2010). Monitoring the polymerization process of polypyrrole films by thermogravimetric and X-ray analysis. Journal of Thermal Analysis and Calorimetry, 102(2), 695-701. doi:10.1007/s10973-010-0870-1Andanson, J.-M., & Kazarian, S. G. (2008). In situ ATR-FTIR Spectroscopy of Poly(ethylene terephthalate) Subjected to High-Temperature Methanol. Macromolecular Symposia, 265(1), 195-204. doi:10.1002/masy.200850521Al-Jabareen, A., Illescas, S., Maspoch, M. L., & Santana, O. O. (2010). Effects of composition and transesterification catalysts on the physico-chemical and dynamic properties of PC/PET blends rich in PC. Journal of Materials Science, 45(24), 6623-6633. doi:10.1007/s10853-010-4753-4Gregory, R. V., Kimbrell, W. C., & Kuhn, H. H. (1989). Conductive textiles. Synthetic Metals, 28(1-2), 823-835. doi:10.1016/0379-6779(89)90610-3Textor, T., & Mahltig, B. (2010). A sol–gel based surface treatment for preparation of water repellent antistatic textiles. Applied Surface Science, 256(6), 1668-1674. doi:10.1016/j.apsusc.2009.09.09

Correlations between acoustic and electrochemical measurements for metallic corrosion on steel strings used in guitars

The corrosion state of steel guitar strings and their morphology were evaluated according to exposure time to artificial human sweat solution. The instantaneous corrosion rate was evaluated using polarization resistance. Electrochemical impedance spectroscopy was used to measure the strings' state due to corrosion in artificial human sweat solution. Modification of vibroacoustic parameters was analyzed: changes in harmonic content of sound were studied by means of the Fast Fourier Transform and spectrograms. The correlation between corrosion and acoustic measurements was established in the successive stages of corrosion. Thus, the strings' acoustic properties could be modified by means of controlled corrosion processes. (C) 2015 Elsevier Ltd. All rights reserved.The authors wish to thank to the Spanish Ministerio de Ciencia e Innovacion (contract CTM2011-23583) for the financial support.López Muelas, JL.; Bonastre Cano, JA.; Segura Alcaraz, JG.; Gadea Borrell, JM.; Juliá Sanchis, E.; Cases Iborra, FJ. (2015). Correlations between acoustic and electrochemical measurements for metallic corrosion on steel strings used in guitars. Engineering Failure Analysis. 57:270-281. https://doi.org/10.1016/j.engfailanal.2015.07.014S2702815

Chemical, electrical and electrochemical characterization of hybrid organic/inorganic polypyrrole/PW12O403- coating deposited on polyester fabrics

A study of the stability of conducting fabrics of polyester (PES) coated with polypyrrole/PW12O403¿ (organic/inorganic hybrid material) in different pH solutions (1, 7, 13) has been done. Washing tests were also done in views of its possible application in electronic textiles such as antistatic clothing. X-ray photoelectron spectroscopy (XPS) studies have been done to quantify the amount of counter ion that remains in the polymer matrix and determine the doping ratio (N+/N) after the different tests. Scanning electron microscopy (SEM) was also used to observe morphological differences after the different tests. Surface resistivity changes were measured by means of electrochemical impedance spectroscopy (EIS). Scanning electrochemical microscopy (SECM) was employed to measure changes in electroactivity after the different tests. Higher pHs caused a decrease of the doping ratio (N+/N), the loss of part of the counter ions and the decrease of its conducting and electrocatalytic properties. The stability in acid media and neutral media and after the washing test was good. Only at pH 13 the loss of the counter ion was widespread and there was a decrease of its conducting and catalytic properties; although the fabrics continued acting mainly as a conducting material.Authors thank the Spanish Ministerio de Ciencia y Tecnologia, European Union Funds (FEDER) (contract CTM2007-66570-C02-02) and Universitat Politecnica de Valencia (Programa de apoyo a la investigacion y desarrollo de la UPV (PAID-05-08)) for the financial support. J. Molina is grateful to the Conselleria d'Educacio (Generalitat Valenciana) for the FPI fellowship. A.I. del Rio is grateful to the Spanish Ministerio de Ciencia y Tecnologia for the FPI fellowship.Molina Puerto, J.; Fernández Sáez, J.; Del Río García, AI.; Bonastre Cano, JA.; Cases Iborra, FJ. (2011). Chemical, electrical and electrochemical characterization of hybrid organic/inorganic polypyrrole/PW12O403- coating deposited on polyester fabrics. Applied Surface Science. 257:10056-10064. doi:10.1016/j.apsusc.2011.06.140S100561006425

Study on the specific capacitance of an activated carbon cloth modified with reduced graphene oxide and polyaniline by cyclic voltammetry

This work describes a two-step process for the electrochemical coating of reduced graphene oxide (RGO) and polyaniline (PANI) onto an activated carbon cloth (ACC) by cyclic voltammetry (CV). The fact that the two syntheses are carried out independently of each other, makes it possible to select the experimental conditions for each one and to study the electrochemical response of RGO, PANI, and PANI onto RGO (RGOPANI), separately. Thus, by modifying the potential limits of the aniline-polymerization reaction, it was possible to observe the influence of RGO and the maximum amount of PANI that the carbon cloth can receive in terms of proper electrochemical response. Electrochemical properties were characterized by CV, galvanostatic charge-discharge curves (using three or two-electrodes symmetric cell configurations) and electrochemical impedance spectroscopy (EIS). A maximum improvement of 25%, 56% and 61% over the initial specific capacitance of ACC (about 129 F g−1) were obtained for RGO, PANI and RGOPANI coatings, respectively. Good cycling stability retaining 83% of the initial capacitance, after 1000 cycles stability test, was obtained for RGOPANI sample. Promising results of energy and power densities were also achieved. In the analyses by Fourier transform infrared spectroscopy (FTIR), the PANI-bands could be clearly identified which is indicative of a significant presence of PANI. Field emission scanning electron microscopy (FESEM) showed the morphology of RGO, PANI and RGOPANI onto the ACC fibers. These analyses helped to explain the electrochemical results.The authors wish to acknowledge to Chemviron Carbon who kindly donated the ZORFLEX (R) activated carbon fabric. The authors wish to thank the Spanish Agenda Estatal de Investigacion (AEI) and European Union (FEDER funds) for the financial support (contract MAT2016-77742-C2-1-P). Tim Vickers is gratefully acknowledged for help with the English revision.Fernández Sáez, J.; Bonastre Cano, JA.; Molina Puerto, J.; Del Río García, AI.; Cases Iborra, FJ. (2017). Study on the specific capacitance of an activated carbon cloth modified with reduced graphene oxide and polyaniline by cyclic voltammetry. European Polymer Journal. 92:194-203. doi:10.1016/j.eurpolymj.2017.04.044S1942039