Journal of Solid State Electrochemistry | Year: 2010
The effect of thermal annealing of poly(3-octylthiophene) (P3OT) and polystyrene (PS) blend coatings on the corrosion inhibition of stainless steel in a 0.5 M NaCl solution was investigated. P3OT was synthesized by direct oxidation of the 3-octylthiophene monomer with ferric chloride (FeCl 3) as oxidant. Stainless steel electrodes with mirror finish were coated with P3OT/PS blend by dropcasting technique. In order to study the temperature effect on the function like physical barrier against the corrosive species of P3OT/PS polymeric blend, the coatings were thermally annealed at three different temperatures (55°C, 80°C, and 100°C). The corrosion behavior of P3OT/PScoated stainless steel was investigated in 0.5 M NaCl at room temperature, by using potentiodynamic polarization curves, linear polarization resistance (LPR), and electrochemical impedance spectroscopy. The LPR values indicated that, at 100°C, P3OT/PS coatings showed a better protection of the 304 stainless steel in 0.5 M NaCl; the corrosion rate diminished in two orders of magnitude with regard to the bare stainless steel. The superficial morphology of the coatings before and after the corrosive environment was researched by atomic force microscopy, optic microscopy, and scanning electronic microscopy. Morphological study showed that the increased temperature benefited the integration of the two polymeric phases, which improved the barrier properties of the coatings. The coating/metal adhesion and the coating thickness were evaluated. The temperature increases the adhesion degree coating/substrate; thus, the coating annealed at 100°C showed the best adhesion. © Springer-Verlag 2009.
Cervantes-Navarro F.,CIMAV |
Journal of Photochemistry and Photobiology A: Chemistry | Year: 2013
Theoretical analyses of the indigo dye molecule and its derivatives with Chlorine (Cl), Sulfur (S), Selenium (Se) and Bromine (Br) substituents, were performed using the Gaussian 09 software package. Calculations were performed based on the framework of density functional theory (DFT) with the Becke 3-parameter-Lee-Yang-Parr (B3LYP) functional, where the 6-31G(d,p) basis set was employed. All this for study they properties for be used with metal oxides in dye-sensitized solar cells (DSSC). Each of the molecules was theoretically analyzed. According to this results all dyes can work for DSSC with TiO 2, while no one can work with ZnO, and just Indigo can work with (ZnO)12. © 2013 Elsevier B.V. All rights reserved.
Sanchez-Dominguez M.,CIMAV |
Pemartin K.,CIBER ISCIII |
Boutonnet M.,KTH Royal Institute of Technology
Current Opinion in Colloid and Interface Science | Year: 2012
In this review, the synthesis of inorganic nanoparticles using oil-in-water (O/W) microemulsions as confined reaction media is discussed. Synthesis using (O/W) microemulsions has been demonstrated for a great variety of inorganic nanoparticles: metallic (Pt, Pd, Rh, Ag), single metal oxides (CeO 2, ZrO 2, TiO 2, Fe 2O 3), mixed and doped metal oxides (Ce 0.5Zr 0.5O 2, Ce 0.99Eu 0.01O 2, Zr 0.99Eu 0.01O 2, and Fe 2Mn 0.5Zn 0.5O 4), semiconductors (PbS, CdS, Ag 2S, ZnS, CdSe, PbSe, Ag 2Se), fluorides (CaF 2, YF 3, NdF 3, PrF 3), phosphates (CePO 4, HoPO 4), and chromates (BaCrO 4 and PbCrO 4). There are two synthetic strategies: 1) the use of oil-in water (O/W) microemulsions, in which the precursor is an ionic salt which is dissolved in the continuous aqueous phase; and 2) use of O/W microemulsions, in which the precursor is an organometallic salt dissolved in the oil droplets of the microemulsion. The latter approach keeps more resemblance to the typical W/O microemulsion reaction method, as it has the greatest level of precursor confinement. © 2012 Elsevier Ltd.
Procedia Computer Science | Year: 2013
The M06 family of density functionals has been assessed for the calculation of the molecular structure and properties of the Rhodamine B molecule. The chemical reactivity descriptors have been calculated through Conceptual DFT. The active sites for nucleophilic and electrophilic attacks have been chosen by relating them to the Fukui function indices and the dual descriptor f (2)(r). A comparison between the descriptors calculated through vertical energy values and those arising from the Koopmans' theorem approximation have been performed in order to check for the validity of the last procedure. © 2013 The Authors. Published by Elsevier B.V.
Chemistry Central Journal | Year: 2013
Background: Chemicals generically referred to as flavonoids belong to the group of phenolic compounds and constitute an important group of secondary metabolites due to their applications as well as their biochemical properties. Flavonoids, which share a common benzo- γ-pyrone structure, constitute a kind of compound which are highly ubiquitous in the plant kingdom.Findings: The M06 family of density functionals has been assessed for the calculation of the molecular structure and properties of the Naringenin flavonoid. The chemical reactivity descriptors have been calculated through Conceptual DFT. The active sites for nucleophilic and electrophilic attacks have been chosen by relating them to the Fukui function indices and the dual descriptor f(2)(r). A comparison between the descriptors calculated through vertical energy values and those arising from the Koopmans' theorem approximation have been performed in order to check for the validity of the last procedure.Conclusions: The M06 family of density functionals (M06, M06L, M06-2X and M06-HF) used in the present work leads to the same qualitatively and quantitatively similar description of the chemistry and reactivity of the Naringenin molecule, yielding reasonable results. However, for the case of the M06-2X and M06-HF density functionals, which include a large portion of HF exchange, the calculations considering the validity of the Koopmans' theorem lead to negative electron affinities. © 2013 Glossman-Mitnik; licensee Chemistry Central Ltd.
Cokun E.,CSIC - Institute of Polymer Science and Technology |
Cokun E.,CIMAV |
Zaragoza-Contreras E.A.,CIMAV |
Salavagione H.J.,CSIC - Institute of Polymer Science and Technology
Carbon | Year: 2012
The sulfonation of graphene by coupling with the diazonium salts of sulfanilic (SA) acid and amino-4-hydroxy-2-naphthalenesulfonic (NSA) acid is studied. Coupling with the diazonium salt of NSA gives the highest degree of sulfonation. Composites of polyaniline (PANI) and sulfonated graphene (SG) are prepared by the polymerization of aniline in the presence of the SG. The materials have been characterized by Raman, Fourier transformed infrared spectroscopy, thermogravimetric analysis and cyclic voltammetry. These materials are electrochemically active at pHs close to physiological pH due to the doping of PANI with the sulfonic groups in SG trapped in the polymer. Furthermore, good conductivity values are obtained. © 2011 Elsevier Ltd. All rights reserved.
Garay-Tapia A.M.,CINVESTAV |
Garay-Tapia A.M.,CIMAV |
Romero A.H.,CINVESTAV |
Barone V.,Central Michigan University
Journal of Chemical Theory and Computation | Year: 2012
We have studied Li adsorption on graphene for Li concentrations ranging from about 1% to 50% by means of density functional theory calculations. At low adsorbant densities, we observe a strong ionic interaction characterized by a substantial charge transfer from the adatoms to the substrate. In this low concentration regime, the electronic density around the Li adatoms is well localized and does not contribute to the electronic behavior in the vicinity of the Fermi level. For larger concentrations, we observe the formation of a chemically bound Li layer characterized by a stronger binding energy as well as a significant density of states above the Fermi level coming from both graphene and the two-dimensional Li sheet. © 2012 American Chemical Society.
Agency: European Commission | Branch: FP7 | Program: CP-FP | Phase: NMP.2010.1.2-4 | Award Amount: 4.04M | Year: 2010
Silver nanoparticles and silver based nanostructured composites are being frequently used in a variety of biomedical and industrial applications, such as an antimicrobial agents, lead-free solders, electric contact materials, gas-sensitive sensor, etc. The most complicated Silver using problems are related to: i) recovery of silver from ore waste materials; ii) the controlled synthesis of metal nanoparticles of well-defined size, shape and composition; iii) nanoparticles incorporation to desired implant surfaces; iv) synthesis of Silver based nanostructured composites for industrial purposes. The main goal of the Project is to develop: 1. Clean and efficient procedure of silver recovery from waste: Combined Mechanical Activation Thermal Oxidation Processing jarosite type residues to alleviate and accelerate the following precious metal leaching; 2. Combined nanotechnology of biological synthesis (use of plants for the nanoparticles synthesis) of Ag nanoparticles and its deposition on implant surfaces by electrophoretic and plasma spraying deposition; 3. Nanostructuring technology of Silver based nanocomposites manufacturing for electrical contact applications. Pilot production and trials of developed Ag nanoparticle modified implants and Ag based nanostructured composites: 1. TiO2 and Hydroxyapatite Ca10(PO4)6(OH)2) coated implants which are widely used in orthopaedic surgery because of their good biocompatibility related to the osteoconductive properties of calcium phosphate coating; 2. Ag-SnO contacts for electrical systems; these composites combine high resistance to welding and to electric arch erosion of the refractory phases with the high electric and thermal conductivities.
Agency: European Commission | Branch: FP7 | Program: CP-FP | Phase: NMP.2010.1.2-4 | Award Amount: 3.75M | Year: 2010
Successful adaptation of nanotechnology in the end-products requires an access to the nanofiller technology and to the raw materials. The MINANO-project brings together partners representing end-users product know-how, formulation and processing technology and most importantly secure and reliable source of nano raw materials. Although there has been tremendous development in the area of nanocompounds with improved functionality, there exists a need to develop an efficient, continuous method of large-scale, low-cost synthesis of such materials. To answer to this need the following steps are suggested: 1) Integrate the functionalization of the high-quality nanoparticles directly on the continuous mass-production process already in the mining industry, 2) ensure controlled dispersion to the matrix material in large scale by cooperation between nanoparticle producer and end-product manufacturer, 3) assure sustainable and safe production and use by state-of-the-art life-cycle analysis. Based on the mass production process and cooperative value chain we concentrate on three major functionalities: Flame retardancy, UV resistance and antimicrobial properties. These properties are achieved by functionalized Mg(OH)2, ZnO and Ag nanoparticles. Societal and industrial impacts of these properties are extensive and there is a strong request of these functionalities for both plastic and wood-plastic based matrix materials. The use of nano-sized functional filler materials enables to use smaller amount of additives thus giving better recyclability, lower weight, higher mechanical strength and potential multifunctional features to the end-product. The combination of new nanofunctionalities gives far reaching possibilities for new types of functional plastics, and completely new possibilities to wood-plastic composites as well. This moves both mining industry and end-product companies towards high-tech on the long run.
Agency: European Commission | Branch: FP7 | Program: CSA-SA | Phase: NMP.2013.4.0-5 | Award Amount: 1.12M | Year: 2013
A thorough approach to nanotechnology and advance materials development must take into consideration the international dimension, in terms of R&D, access to information and regulation. International cooperation, including collaboration in research but not limited to this, is an integral part of the Commissions policy in all areas of the Action Plan. However, despite the fact that international collaboration has been made so far; there is still a challenge of filling knowledge gaps with less industrially advanced nations in order to enhance quality of life and industrial competitiveness in those areas where Nanotechnology has the potential. European industrial players and research organizations seek new collaborative agreements in order to share risks and explore new market opportunities. On the other hand, Latin America has started new nanotechnology development programs in the last ten years. However, according to national agencies, the investment in nanotechnology R\D and the results achieved remains now relatively unpretentious. The main objective of NMP-DeLA project is to develop a series of activities between European and Latin American countries, aiming to strengthening the local research and training potential, as means to achieve the goal of deployment of Nanomaterials technologies on those areas of major social challenge in Latin America: energy, water and Health. This will be achieved through: Networking, education and training in Advance materials (nanosciences, nanotechnologies, materials and new production techs). Building new skills, aiming to enhance and strengthening the local knowledge in Latin America about nanomaterial technologies. Boost synergy with local/regional policy and cooperation programs related to advance materials. Exchange of best practices, build capacity in nanomaterial-innovation and technology transfer in cooperation with central and south America. Contribute toward the United Nations Millennium development goals.