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Gomez-Romero P.,Catalan Institute of Nanoscience and Nanotechnology | Gomez-Romero P.,Research Center | Fraile J.,ICMAB CSIC | Ballesteros B.,Catalan Institute of Nanoscience and Nanotechnology
RSC Advances | Year: 2013

A simple modification of a combustion method has been used for the production of ultraporous metals in air. Nitrates of different metallic elements were reacted with glycine as a reducing fuel. The glycine to nitrate ratio can be simply used to control the formation of oxides or, in the case of fuel-rich mixtures, the formation of metals such as Ni, Co, Cu or Ag. Furthermore, the metallic monoliths obtained present a remarkable porosity of fractal nature (from macro to nano scales) with pores ranging from many microns down to at least 5 nm. This exceedingly simple approach shows the way for the design and synthesis of complex porous microstructures of metals for the wide variety of applications where interface optimization is crucial. © 2013 The Royal Society of Chemistry.


Amoros J.,Polytechnic University of Catalonia | Carrera M.,University of Lleida | Granados X.,ICMAB CSIC
Superconductor Science and Technology | Year: 2012

Computation of the current distribution of superconducting devices is an important topic in the understanding of the behavior of superconducting materials, in the development of their applications and in testing the quality of the materials. The most successful technique to measure the currents is based on mapping the magnetic field in the surface of the superconducting sample during or after a magnetization process. Models for solving the inverse problem have been developed based on different techniques. The inversion technique based on considering the currents as the result of a distribution of magnetic moments has been tested for many years in the description of the currents in bulks, giving a useful tool for their characterization, including junctions and porous samples. The restriction of this technique to closed loops of currents does not allow its application to the exploration of superconducting wires. Specific considerations developed for this technique have, however, allowed extension of the technique to the study of HTS tapes in a simple and fast way that can be applied to the exploration of long tapes to determine the current distribution on the fly. In this work we report on the model and the procedure to perform the calculation of currents on tapes carrying current. The specific application to the detection of defects that do not affect the ability to carry current, such as longitudinally centered scratches, is experimentally tested. Details of the application of the method for long tapes are also reported. © 2012 IOP Publishing Ltd.


Aragay G.,Institute of Chemical Research of Catalonia | Frontera A.,University of the Balearic Islands | Lloveras V.,ICMAB CSIC | Lloveras V.,CIBER ISCIII | And 4 more authors.
Journal of the American Chemical Society | Year: 2013

We report experimental evidence indicating that the nature of the interaction established between HAT(CN)6, a well-known strong electron acceptor aromatic compound, with mono-or polyatomic anions switches from the almost exclusive formation of reversible anion-π complexes, featuring a markedly charge transfer (CT) or formal electron-transfer (ET) character, to the quantitative and irreversible net production of the anion radical [HAT(CN)6]•- and the dianion [HAT(CN) 6]2- species. The preferred mode of interaction is dictated by the electron donor abilities of the interacting anion. Thus, weaker Lewis basic anions such as Br- or I- are prone to form mainly anion-π complexes. On the contrary, stronger Lewis basic F- or -OH anions display a net ET process. The ET process can be either thermal or photoinduced depending on the HOMO/LUMO energy difference between the electron donor (anion) and the electron acceptor (HAT(CN)6). These ET processes possibly involve the intermediacy of anion-π complexes having strong ET character and producing an ion-pair radical complex. We hypothesize that the irreversible dissociation of the pair of radicals forming the solvent-caged complex is caused by the reduced stability (high reactivity) of the radical resulting from the anion. © 2013 American Chemical Society.


Pasker F.M.,University of Bonn | Klein M.F.G.,Karlsruhe Institute of Technology | Sanyal M.,Max Planck Institute for Intelligent Systems (Stuttgart) | Barrena E.,ICMAB CSIC | And 3 more authors.
Journal of Polymer Science, Part A: Polymer Chemistry | Year: 2011

The synthesis, characterization, and photovoltaic properties of a series of four conjugated polymers containing 2-aryl-2H-benzotriazoles and "bis(thiopheno)dialkylfluorenes" is described. The polymers were obtained via Suzuki-polycondensation and comprise alternating electron rich and electron poor building blocks. The impact of systematic structural changes on the electronic and morphological properties and device efficiencies were studied. Application of these polymers as light-harvesting and electron-donating materials in organic solar cells using PCBM derivatives as electron accepting materials resulted in power conversion efficiencies up to 1.8%. Both the properties of the pristine polymers and the device performance show that the impact of the substitution farther-off the backbone is negligible while substitution directly on the backbone has a major impact. © 2011 Wiley Periodicals, Inc.


Bastos-Gonzalez D.,University of Granada | Perez-Fuentes L.,University of Granada | Drummond C.,CNRS Paul Pascal Research Center | Faraudo J.,ICMAB CSIC
Current Opinion in Colloid and Interface Science | Year: 2016

It is increasingly being accepted that solvation properties of ions and interfaces (hydration of ions, hydrophobic or hydrophilic character of interfaces) play a fundamental role in ion-surface interaction in water. However, a fundamental understanding of the precise role of solvation in ionic specificity in colloidal systems is still missing, although important progress has been made over the last years. We present in this contribution experimental evidences (including also ions not usually included in specific ion studies) together with Molecular Dynamics (MD) simulations that highlight the importance of the hydration of ions and surfaces in order to understand the origin of ionic specificity. We first show that both surface polarity and ion hydration determine the sorting of ions according to their ability to induce specific effects (the so-called Hofmeister series). We extend these classical series by considering the addition of the inorganic anions IO3 -, BrO3 - and ClO3 -, which present unusual properties as compared with the ions considered in classical Hofmeister series. We also consider big hydrophobic organic ions such as tetraphenylborate anion (Ph4B-) and tetraphenylarsonium cation (Ph4As+) that in the context of the Hofmeister series behave as super-chaotropes ions. © 2016 Elsevier Ltd.


Arin M.,Ghent University | Lommens P.,Ghent University | Hopkins S.C.,University of Cambridge | Pollefeyt G.,Ghent University | And 5 more authors.
Nanotechnology | Year: 2012

In this paper, we present an inkjet printing approach suited for the deposition of photocatalytically active, transparent titanium oxide coatings from an aqueous, colloidal suspension. We used a bottom-up approach in which a microwave-assisted hydrothermal treatment of titanium propoxide aqueous solutions in the presence of ethylenediaminetetraacetic acid and triethanolamine was used to create suspensions containing titania nanoparticles. Different inkjet printing set-ups, electromagnetic and piezoelectric driven, were tested to deposit the inks on glass substrates. The presence of preformed titania nanoparticles was expected to make it possible to reduce the heating temperature necessary to obtain the functionality of photocatalysis which can widen the application range of the approach to heat-sensitive substrates. We investigated the crystallinity and size of the obtained nanoparticles by electron microscopy and dynamic light scattering. The rheological properties of the suspensions were evaluated against the relevant criteria for inkjet printing and the jettability was analyzed. The photocatalytic activity of the obtained layers was analyzed by following the decomposition of a methylene blue solution under UV illumination. The influence of the heat treatment temperature on the film roughness, thickness and photocatalytic activity was studied. Good photocatalytic performance was achieved for heat treatments at temperatures as low as 150°C, introducing the possibility of using this approach for heat-sensitive substrates. © 2012 IOP Publishing Ltd.


Brusselle D.,CNRS Marcoule Institute for Separative Chemistry | Bauduin P.,CNRS Marcoule Institute for Separative Chemistry | Girard L.,CNRS Marcoule Institute for Separative Chemistry | Zaulet A.,ICMAB CSIC | And 4 more authors.
Angewandte Chemie - International Edition | Year: 2013

B in phase: Lyotropic lamellar phases can not only be formed from alkyl-chain-based surfactants with a well-defined amphiphilic structure, now they can be obtained from metallacarborane clusters, described as θ-shaped amphiphiles. The lamellae formed are unique as they have a monomolecular thickness. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Bauduin P.,CNRS Marcoule Institute for Separative Chemistry | Prevost S.,Helmholtz Center Berlin | Farras P.,ICMAB CSIC | Teixidor F.,ICMAB CSIC | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2011

Sandwiched: The cobaltabisdicarbollide (mono-)anion ([3,3′-Co(1,2- C2B9H11)2]-, COSAN -) forms monolayer vesicles at low concentrations in water (see picture). An increase in concentration leads to a Coulomb explosion of the closely packed vesicles into small micelles, which results in the coexistence of both aggregation states at higher concentrations. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Roy C.,University of Paris 13 | Vega-Gonzalez A.,University of Paris 13 | Garcia-Gonzalez C.A.,ICMAB CSIC | Tassaing T.,CNRS Institute of Molecular Sciences | And 2 more authors.
Journal of Supercritical Fluids | Year: 2010

In order to effectively exploit the remarkable properties of fine particles to form hybrid nanostructured composites with applications in the biomedical area, one essential step is their surface functionalization. The overall objective of the present work was to use supercritical carbon dioxide (scCO 2) for the design of the surface of inorganic particles by depositing thin and ultrathin films. Two scCO2 routes were proposed to modify the surface of micro- (SiO2, 5 μm) and nanometric (TiO 2, 20-30 nm) oxide particles: antisolvent methods for polymers that are non-soluble in CO2 (polymethylmethacrylate), and the use of compressed CO2 as a solvent for modifiers with certain solubility in scCO2 (octadecylsilane, salicylic acid). In the antisolvent technique, solid particles were dispersed in a solution containing the polymer and mixed with scCO2; polymer precipitation, induced by the presence of CO2, occurred preferentially onto the available surface offered by the oxide particles. For CO2-soluble modifiers, the molecules were transferred from the compressed phase to the surface of the solid particles by diffusion; reactivity between adequate moieties permitted to form covalently grafted films. Vibrational ATR-FTIR spectroscopy was used to evaluate potential interactions between samples components. The wettability of the produced systems was analyzed by dispersion experiments in water and toluene. © 2010 Elsevier B.V.


PubMed | ICMAB CSIC and University of Girona
Type: | Journal: Chemistry (Weinheim an der Bergstrasse, Germany) | Year: 2017

The preparation and characterization of new complexes with a phosphonated trpy ligand (trpy-P-Et) and a bidentate pyridylpyrazole (pypz-Me) ligand, with formula [RuII(trpy-P-Et)(pypz-Me)X]n+ (X = Cl, n= 1, 2; X=H2O, n=2, 3) is described, together with the anchoring of 3 onto two types of supports: mesoporous silica particles (SP) and silica coated magnetic particles (MSP). The aqua complex 3 is easily obtained through reflux of 2 in water and displays a bielectronic Ru(IV/II) redox process. It has been anchored onto SP and MSP supports through two different synthetic strategies, yielding the heterogeneous systems SP@3 and MSP@3 that have been fully characterized by IR, UV-vis, SEM, CV and DPV. Catalytic olefin epoxidation has been tested with the molecular complex 3 and the SP@3 and MSP@3 heterogeneous counterparts, including the reuse of the heterogeneous systems. The MSP@3 material can be easily recovered by a magnet facilitating their reusability.

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