- San Sebastian, Pais Vasco, Spain
Research Interests: Chemistry, Bioelectrochemistry, Carbon, Nanofibers, Nanotechnology, and 15 moreMedicine, Food Analysis, Graphite, Biosensor, Platinum, Temperature, Beverages, Reproducibility of Results, Platinum Nanoparticles, Electrodes, Lactic Acid, Equipment Design, Biosensing Techniques, Amperometry, and Biochemistry and cell biology
The development of distributed pressure sensors based on conducting polymers for automotive application is described. These pressure sensors can be placed on large surfaces due to its flexibility and low cost. As a consequence, pressure... more
The development of distributed pressure sensors based on conducting polymers for automotive application is described. These pressure sensors can be placed on large surfaces due to its flexibility and low cost. As a consequence, pressure data are obtained not only from some discrete points but also from continuous surface points. 256 of these sensors have been placed on an automotive
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Summary:Coinage metal salts (e.g. AuIII, AgI and CuII salts) readily react with thiols to give the corresponding metal(I) thiolates. These thiolate species are known to either self‐assemble into insoluble polymeric species or to form... more
Summary:Coinage metal salts (e.g. AuIII, AgI and CuII salts) readily react with thiols to give the corresponding metal(I) thiolates. These thiolate species are known to either self‐assemble into insoluble polymeric species or to form soluble oligomers, depending on the nature of the thiol ligand. Here we demonstrate that this self‐assembling ability can be applied to create supramolecular hydrogels. Glutathione (GSH), a naturally occurring tripeptide, has been used in combination with AuIII, AgI and CuII salts to obtain pH responsive hydrogels that are able to gelate 100 times their weight in water.
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We have studied the kinetics of polymeric nanoparticle formation for poly(styrene‐block‐4‐vinylpyridine) [P(S‐b‐4‐VPy)], chains in a non‐selective solvent using 1,4‐dibromobutane (DBB) as a cross‐linker by means of different nuclear... more
We have studied the kinetics of polymeric nanoparticle formation for poly(styrene‐block‐4‐vinylpyridine) [P(S‐b‐4‐VPy)], chains in a non‐selective solvent using 1,4‐dibromobutane (DBB) as a cross‐linker by means of different nuclear magnetic resonance (NMR) spectroscopy techniques. The kinetic process was followed using 1H, 13C, and 2‐D Heteronuclear Single Quantum Correlation (HSQC) NMR experiments. The kinetic data obtained from 2‐D HSQC and 1H NMR experiments were in good agreement between them, proving the reliability of the 2‐D HSQC NMR technique for the in situ study of the kinetics of core‐shell nanoparticle formation. A value of 1.5 × 10−5 s−1 was determined for the apparent kinetic constant of the P(S‐b‐4‐VPy)‐DBB core‐shell nanoparticle formation process.magnified image
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The ability of gold(I) thiolates to self-assemble into polymeric species has been exploited to create a pH responsive supramolecular hydrogel based on glutathione.
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Research Interests: Chemistry, Analytical Chemistry, Biomedical Engineering, Carbon, Nanofibers, and 15 moreNanotechnology, Medicine, Humans, Biosensor, Platinum, Hydrogen Peroxide, Carbon Nanofiber, Reproducibility of Results, Platinum Nanoparticles, Polyethylenes, Quaternary Ammonium Compounds, Lactic Acid, Biosensing Techniques, Amperometry, and limit of detection
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ABSTRACT Recently we have shown the self-healing ability of a poly(urea-urethane) elastomer reversibly cured with aromatic disulfide bridges. Here we show that although being chemically crosslinked, such materials can be easily... more
ABSTRACT Recently we have shown the self-healing ability of a poly(urea-urethane) elastomer reversibly cured with aromatic disulfide bridges. Here we show that although being chemically crosslinked, such materials can be easily reprocessed by applying heat and pressure to obtain any desired form. This offers a unique paradigm towards thermoset processing and recycling, as well as for isocyanate-free manipulation of polyurethanes.
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In this work the growth of polymer brushes was combined with nanoimprint lithography (NIL) in order to obtain new functional nanopatterns. First, a functional thermoplastic methacrylic copolymer poly(methyl... more
In this work the growth of polymer brushes was combined with nanoimprint lithography (NIL) in order to obtain new functional nanopatterns. First, a functional thermoplastic methacrylic copolymer poly(methyl methacrylate-co-2-bromoisobutyryl-oxy-ethyl methacrylate) was synthesized. This copolymer was successfully patterned by NIL using a silicon stamp at 160 °C and 60 bar. Next, hydrophilic polymer brushes based on poly(3-sulfopropylmethacrylate) and hydrophobic polymer brushes
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ABSTRACT Promising results on flexible and large area pressure sensors for human-neuroprostheses and humanneurobotic interface assessment are presented. Array sensors of 4x4 and 8x8 based on polymer and plastic electronics have been... more
ABSTRACT Promising results on flexible and large area pressure sensors for human-neuroprostheses and humanneurobotic interface assessment are presented. Array sensors of 4x4 and 8x8 based on polymer and plastic electronics have been fabricated and characterized with a resolution of 1 and 0.25 cm2. The working pressure range is between 0 and 1 Kg/cm2 and the offset measured is around 0.03 Kg/cm2. The response time is around 1 ms.
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The synthesis of polymer nanoparticles (NPs) with controlled characteristics has become an appealing research topic lately. Nanomedicine, and especially drug delivery and imaging, are fields that require particles of a controlled size and... more
The synthesis of polymer nanoparticles (NPs) with controlled characteristics has become an appealing research topic lately. Nanomedicine, and especially drug delivery and imaging, are fields that require particles of a controlled size and with a tailored arrangement of functional groups. Intramolecular cross-linking or collapse of single polymer chains has emerged as an efficient alternative for the synthesis of well-defined polymer NPs. This technique allows the generation of 1.5-20 nm particles with a wide variety of chemical compositions and functionalities. This review begins by gathering synthetic strategies described in the literature and groups them into four main synthetic methods: homo-functional collapse, hetero-functional collapse, crosslinker-mediated collapse, and one-block collapse of diblock or triblock copolymers. Afterwards, the main characterization techniques and physical properties of single-chain polymer NPs (SCPNs) are exposed. Finally, several applications in nanomedicine are mentioned followed by some future perspectives.
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A new approach to prepare Pt-based hydrogen diffusion anodes for PEMFCs based on galvanostatic pulsed electrodeposition is demonstrated to be a reliable alternative to the conventional electrode preparation methods. The performance of the... more
A new approach to prepare Pt-based hydrogen diffusion anodes for PEMFCs based on galvanostatic pulsed electrodeposition is demonstrated to be a reliable alternative to the conventional electrode preparation methods. The performance of the PtRu electrodeposited anodes depends on the electrodeposition parameters such as the peak current, on time, off time, and the total charge applied. The peak current density and the relaxation time are crucial in the control of electrode performance. Electrodes prepared using a cathodic peak current of 0.400Acm−2, a duty cycle of 5.66% and a charge density of 6Ccm−2 demonstrate high catalytic performance towards hydrogen oxidation.
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In this article, a disposable magnetic DNA sensor using an enzymatic amplification strategy for the detection of specific hybridization processes, based on the coupling of streptavidin-peroxidase to biotinylated target sequences, has been... more
In this article, a disposable magnetic DNA sensor using an enzymatic amplification strategy for the detection of specific hybridization processes, based on the coupling of streptavidin-peroxidase to biotinylated target sequences, has been developed. A thiolated 19-mer capture probe was attached to gold coated ferric oxide nanoparticles and hybridization with the biotinylated target was allowed to proceed. Then, a streptavidin-peroxide was attached to the biotinylated target and the resulting modified gold coated ferric oxide nanoparticles were captured by a magnetic field on the surface of a home-made carbon screen printed electrode (SPE). Using hydroquinone as a mediator, a square wave voltammetric procedure was chosen to detect the hybridization process after the addition of hydrogen peroxide. Different aspects concerning the assay protocol and nanoparticles fabrication were optimized in order to improve the sensitivity of the developed methodology. A low detection limit (31 pM) with good stability (RSD=7.04%, n=10) was obtained without the need of polymerase chain reaction (PCR) amplification.
Research Interests: Chemistry, Analytical Chemistry, Biomedical Engineering, Magnetic field, In Situ Hybridization, and 15 moreGold, Magnetic nanoparticles, DNA hybridization, Iron Oxide Nanoparticles, Hydrogen Peroxide, Development Methodology, Disposable Equipment, Magnetic Nanoparticles, Equipment Design, Equipment Failure Analysis, Ferric Compounds, Hydroquinone, Biosensing Techniques, Colloidal Gold, and Biotinylation
By electrochemical stimulation of conformational changes along a chain of a conjugated polymer a molecular muscle is obtained. The electrochemically stimulated conformational relaxation model allows a good theoretical description of the... more
By electrochemical stimulation of conformational changes along a chain of a conjugated polymer a molecular muscle is obtained. The electrochemically stimulated conformational relaxation model allows a good theoretical description of the electrochemical chronoamperograms, voltammograms or chronocoulograms performed under influence of different chemical or physical variables. Electrochemical and structural magnitudes were integrated in the same model. Through a geometrical model three dimensional processes (change of volume) occurring in polymeric films were transformed in one dimensional change, describing bilayer effects, angles described by a bilayer muscle and angular movements as a function of the current flowing by the device. Being the current a function of both, electrochemical and structural magnitudes, angular movements can be described as a function of then.
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Abstract In this study, flexible plastic electrochromic devices (ECDs) based on viologen-modified TiO2 nanostructured films thermally treated at only 120 °C are reported. Even if a sintering process at typically above 450 °C was avoided,... more
Abstract In this study, flexible plastic electrochromic devices (ECDs) based on viologen-modified TiO2 nanostructured films thermally treated at only 120 °C are reported. Even if a sintering process at typically above 450 °C was avoided, the resulting mesoporous TiO2 films were highly transparent on both TCO-coated glass and plastic substrates while presenting adequate conductivity and high active surface area suitable for anchoring electro-chromophores. The synthesis of a viologen specifically designed to provide colorless-to-blue switching while being more compatible with plastic substrates than the traditional ethyl viologen is reported as well. The effect of the TiO2 layer thickness and pore characteristics as well as the grafting time on the device performance were also investigated. Transparent ECDs based on these viologen-modified TiO2 films have been assembled on flexible plastic substrate (ITO/PET) offering transmittance changes (ΔT) above 60% and switching speeds of 6–8 s. The change in transmittance is further enhanced up to 71% in dual ECDs using PB on ITO/PET as the counter electrode and viologen-modified TiO2 films on FTO/glass. Finally, operational large-area all-solid devices (40 cm×30 cm) are presented, demonstrating the suitability of the present technology for the production of large-area plastic ECDs.
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The solution processing of pinhole-free methylammonium lead triiodide perovskite-C70 fullerene (MAPbI3 :C70 ) blend films on fluorine-doped tin oxide (FTO)-coated glass substrates is presented. Based on this approach, a simplified and... more
The solution processing of pinhole-free methylammonium lead triiodide perovskite-C70 fullerene (MAPbI3 :C70 ) blend films on fluorine-doped tin oxide (FTO)-coated glass substrates is presented. Based on this approach, a simplified and robust protocol for the preparation of efficient electron-transport layer (ETL)-free perovskite solar cells is described. Power conversion efficiency (PCE) of 13.6 % under AM 1.5 G simulated sunlight is demonstrated for these devices. Comparative impedance spectroscopy and photostability analysis of the MAPbI3 :C70 and single MAPbI3 films compared with conventional compact TiO2 ETL-based devices are shown. The beneficial impact of using MAPbI3 :C70 blend films is emphasized.
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Summary form only given. The electrochemical oxidation of conducting polymers such as polypyrrole or polythiophene, requires the simultaneous incorporation of counterions into the polymer structure to compensate positive charges. The... more
Summary form only given. The electrochemical oxidation of conducting polymers such as polypyrrole or polythiophene, requires the simultaneous incorporation of counterions into the polymer structure to compensate positive charges. The process is accompanied by a molecular movement in the polymer, promoting the opening of chanels across the polymeric entanglement. When the polymer is reduced those processes are reversed and the molecular structure experiments a compactation process. The influence of the molecular entanglement opening and closing during oxidation or reduction is shown as a maximum in the chronoamperometric responses, or as an induction time in the charge time or current-voltage evolutions. In this work the chronoamperometric curves corresponding to the doping processes of polypyrrole films, have been simulated from theoretical models of relaxation processes in non crystalline polymers. A good correlation between experimental and theoretical results was obtained.
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A new technology of flexible all-plastic pressure sensors is developed using conducting polymers as electroactive materials on plastic substrates. The lithography of one of the conducting sheets being part of the device makes feasible the... more
A new technology of flexible all-plastic pressure sensors is developed using conducting polymers as electroactive materials on plastic substrates. The lithography of one of the conducting sheets being part of the device makes feasible the construction of a distributed pressure sensor giving not only the cuantitative pressure information but also its spatial distribution. A response time as low as 2
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... TF Otero, H. Grande, J. Rodriguez Laboratorio de Electroquhica, Facultad de Quhica, UPV/EHU, PO Box 1072, 20080 San Sebastidn, Spain ... and repulsion between charged chains has been correlated to the mechanical strain during stress... more
... TF Otero, H. Grande, J. Rodriguez Laboratorio de Electroquhica, Facultad de Quhica, UPV/EHU, PO Box 1072, 20080 San Sebastidn, Spain ... and repulsion between charged chains has been correlated to the mechanical strain during stress relaxation in a Voight-Kelvin element. ...
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An improved method, based on mechanical stirring and a controlled solvent evaporation process, is proposed to obtain PANI(CSA) 0.5 /m-cresol solutions, which lead to gels with conductivities in the range 3 to 150 S/cm, preserving the... more
An improved method, based on mechanical stirring and a controlled solvent evaporation process, is proposed to obtain PANI(CSA) 0.5 /m-cresol solutions, which lead to gels with conductivities in the range 3 to 150 S/cm, preserving the elasticity associated to the gel network. Such ...
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We report the phase behavior of nanocomposites composed of weakly-charged flexible polymers and polar nanoparticles by extending a mean-field theory for all-polymer nanocomposites recently introduced (Journal of Nano Research 2 (2008)... more
We report the phase behavior of nanocomposites composed of weakly-charged flexible polymers and polar nanoparticles by extending a mean-field theory for all-polymer nanocomposites recently introduced (Journal of Nano Research 2 (2008) 105). Translational, nanoparticle-driven, electrostatic and enthalpic interaction effects are taken into account. Weakly-charged polymers are predicted to be miscible with polar nanoparticles about one order of magnitude larger (in radius) than conventional uncharged polymers, even in the presence of moderate unfavorable enthalpic interactions. The detrimental effect of addition of a low molecular weight monovalent 1-1 salt on nanocomposite miscibility is also evaluated.
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A compressible regular solution free energy model for describing the phase behavior of weakly interacting binary blends comprising nonrigid polymer nanoparticles and linear-polymer chains (i.e., all-polymer nanocomposites) has been... more
A compressible regular solution free energy model for describing the phase behavior of weakly interacting binary blends comprising nonrigid polymer nanoparticles and linear-polymer chains (i.e., all-polymer nanocomposites) has been developed by incorporating specific nanoparticle-nanoparticle and nanoparticle-polymer contributions into the original free volume theory for binary polymer blends of Ruzette et al. [J. Chem. Phys. 114, 8205 (2001)]. The extended model allows predicting phase behavior for weakly interacting polymer-nanoparticle/linear-polymer nanocomposites using only pure component properties (nanoparticle and polymer sizes, mass densities, coefficients of thermal expansion, and solubility parameters). The effect of polymer and nanoparticle size, as well as those arising from nanoparticle rigidity, exchange interaction energy and composition on the phase behavior of all-polymer nanocomposites have been systematically investigated. A rich variety of phase diagrams (including upper critical solution temperature-type, lower critical solution temperature-type, and hour-glass shape) are illustrated. Predicted phase diagrams for nonrigid poly(styrene)-nanoparticle (PS-np)/linear-poly(styrene) (l-PS), and branched poly(ethylene)-nanoparticle (PE-np)/l-PS nanocomposites were in excellent agreement with available experimental data.
Research Interests: Engineering, Materials Science, Chemistry, Nanoparticle, Chemical Physics, and 14 moreMedicine, Polymer, Nanocomposite, Physical sciences, Free Energy, CHEMICAL SCIENCES, Free volume, Polymer Blend, Thermal Expansion, Phase Behavior, Experimental Data, Polymer Nanocomposite, Coefficient of Thermal Expansion, and phase diagram
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Effect of Gas Diffusion Layer Composition on the Performance of Direct Methanol Fuel Cells. [Electrochemical and Solid-State Letters 13, B73 (2010)]. Francisco Alcaide, Garbiñe Álvarez, Pere L. Cabot, Hans-Jürgen Grande, Oscar Miguel.... more
Effect of Gas Diffusion Layer Composition on the Performance of Direct Methanol Fuel Cells. [Electrochemical and Solid-State Letters 13, B73 (2010)]. Francisco Alcaide, Garbiñe Álvarez, Pere L. Cabot, Hans-Jürgen Grande, Oscar Miguel. Abstract. ...