Graphic summary
  • Show / hide key
  • Information


Scientific and technological production
  •  

1 to 50 of 498 results
  • All-polythiophene rechargeable batteries

     Aradilla Zapata, David; Estrany Coda, Francisco; Casellas Beneyto, Francisco; Iribarren Laco, Jose Ignacio; Aleman Llanso, Carlos Enrique
    Organic electronics
    Date of publication: 2014-01-01
    Journal article

     Share Reference managers Reference managers Open in new window

  • Measuring the proton conductivity of ion-exchange membranes using electrochemical impedance spectroscopy and Through-Plane cell

     Müller, Franciélli; Ferreira, Carlos A.; Azambuja, Denise S.; Aleman Llanso, Carlos Enrique; Armelin Diggroc, Elaine
    Journal of physical chemistry B
    Date of publication: 2014-01-30
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    The role of the incorporation of conducting polymer (CP), doped with different sulfonic acid organic molecules, in polystyrene (PS) and high-impact polystyrene (HIPS) with poly(styrene-ethylene-butylene) (SEBS) triblock copolymer has been investigated. Two factors associated with this model membrane system are addressed: (i) the influence of the presence of a low concentration of doped conducting polymer and (ii) the influence of the membrane preparation method. Membrane characterization and bulk conductivity measurements allowed the conclusion that proton conductivity has been promoted by the addition of CP; the best results were achieved for PAni-CSA, in either PS/SEBS or HIPS/SEBS blends. Additionally, the water uptake only decreased with the addition of PAni-doped molecules compared to the pure copolymer, without loss of ion-exchange capacity (IEC). Electrodialysis efficiency for HIPS/SEBS (before annealing) is higher than that for HIPS/SEBS (after annealing), indicating that membrane preparation method is crucial. Finally, through-plane cell arrangement proved to be an effective, quick, and time-saving tool for studying the main resistance parameters of isolating polymers, which is useful for application in industry and research laboratories working with membranes for electrodialysis or fuel cells.

  • Mineralization of DNA into nanoparticles of hydroxyapatite

     Bertran Cànovas, Oscar; Del Valle Mendoza, Luis Javier; Revilla Lopez, Guillermo; Chaves Barboza, Gustavo Adolfo; Cardus Andreu, Lluis; Casas Becerra, M. Teresa; Casanovas Salas, Jordi; Turon, Pau; Puiggali Bellalta, Jorge; Aleman Llanso, Carlos Enrique
    Dalton transactions
    Date of publication: 2014-01-07
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Encapsulation of DNA into hydroxyapatite (HAp) has been investigated using a rational approach that involves computer simulation and experimental techniques. The temporal evolution of the radial distribution functions derived from atomistic molecular dynamics simulations of Ca2+, PO 4 3- and OH--containing aqueous solutions in the presence and absence of B-DNA has been used to conclude that the backbone of the double helix acts as a template for HAp growth. More specifically, results reveal the formation of calcium phosphate clusters at the first stages of the simulations, which subsequently re-organize to nucleate HAp. This effect is produced in the absence and, especially, presence, of DNA indicating that the biomolecules do not inhibit but even promote mineral growth. Furthermore, computer simulations suggest that the diffusion of the OH- anions through the inorganic solution is the limiting step for the nucleation of the biomineral. Nanocapsules and crystalline nanorods of HAp containing DNA molecules inside have been prepared by mixing solutions containing Ca 2+ and PO4 3- ions with fish sperm DNA at high pH. The dimensions and morphology of such nanostructures have been examined by transmission electron microscopy, while the characterization of the biomineral has been focused on the identification of DNA inside HAp using infrared, X-ray photoelectron and UV-vis spectroscopies, as well as gel electrophoresis. The biominerals reported in this work are important for biomedical applications requiring the protection of DNA from aggressive environmental conditions. © 2014 The Royal Society of Chemistry.

  • Interactions in dendronized polymers: intramolecular dominates intermolecular

     Cordova Mateo, Ester; Bertran Cànovas, Oscar; Zhang, Baozhong; Vlassopoulos, Dimitris; Pasquino, Rossana; Schlüter, A. Dieter; Kröger, Martin; Aleman Llanso, Carlos Enrique
    Soft matter
    Date of publication: 2014
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    In an attempt to relate atomistic information to the rheological response of a large dendritic object, inter- and intramolecular hydrogen bonds and pi,pi-interactions have been characterized in a dendronized polymer (DP) that consists of a polymethylmethacrylate backbone with tree-like branches of generation four (PG4) and contains both amide and aromatic groups. Extensive atomistic molecular dynamics simulations have been carried out on (i) an isolated PG4 chain and (ii) ten dimers formed by two PG4 chains associated with different degrees of interpenetration. Results indicate that the amount of nitrogen atoms involved in hydrogen bonding is similar to 11% while similar to 15% of aromatic groups participate in pi,pi-interactions. Furthermore, in both cases intramolecular interactions clearly dominate over intermolecular ones, while exhibiting markedly different behaviors. Specifically, the amount of intramolecular hydrogen bonds increases when the interpenetration of the two chains decreases, whereas intramolecular pi,pi-interactions remain practically insensitive to the amount of interpenetration. In contrast, the strength of the corresponding two types of intermolecular interactions decreases with interpenetration. Although the influence of complexation on the density and cross-sectional radius is relatively small, interpenetration affects significantly the molecular length of the DP. These results support the idea of treating DPs as long colloidal molecules.

  • Sequence dependence of C-end rule peptides in binding and activation of > neuropilin-1 receptor

     Zanuy Gomara, David; Kotla, Rohith; Nussinov, Ruth; Teesalu, Tambet; Sugahara, Kazuki N.; Aleman Llanso, Carlos Enrique; Haspel, Nurit
    Journal of structural biology
    Date of publication: 2013-05
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Neuropilin-1 (NRP-1) is a hub receptor that plays an essential role in angiogenesis and vascular permeability. It is over-expressed in the new blood vessels grown by tumor cells and is a target for anti-tumor treatments. Peptides that expose the consensus sequence R/K/XXR/K at the C-terminus (C-end rule or CendR peptides) bind to NRP-1 and are internalized into the cell. We used peptide phage display binding assays and molecular dynamics (MD) simulations to study the potential role of the central residues of CendR peptides in binding and activation of the NRP-1 receptor. The high stability of RPAR-receptor domain complex stems from the formation of a characteristic pattern of three hydrogen bonds between the peptide C-terminus and the residues in the NRP-1 loop III. Any changes in the peptide structure that fail to preserve this triad result in a less-stable complex. We performed a systematic study of RXXR mutants, where X = A/D/S/R/P, in order to test the effect of replacement of A or P on the binding capabilities. Our results, both experimental and computational, show that RRAR, RDAR, RPDR, RPRR and RPPR are capable of binding NRP-1. However, only RPPR and RPRR segments form an optimal organization around loop III with low potential energy. In other analogs, the absence of these stabilizing interactions always results in higher potential energy of the complexes. The binding of RPAR analogs does not guarantee receptor activation; only stable complexes that are properly stabilized via loop III appear able to trigger NRP-1 activation.

  • Polythiophene-g-poly(ethylene glycol) graft copolymers for electroactive scaffolds

     Bendrea, Anca Dana; Fabregat Jove, Georgina; Torras Costa, Juan; Maione, Silvana; Cianga, Ioan; Del Valle Mendoza, Luis Javier; Cianga, Luminita; Aleman Llanso, Carlos Enrique
    Journal of materials chemistry B
    Date of publication: 2013
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    The properties, microscopic organization and behavior as the cellular matrix of an all-conjugated polythiophene backbone (PTh) and well-defined poly(ethylene glycol) (PEG) grafted chains have been investigated using different experimental techniques and molecular dynamic simulations. UV-vis spectroscopy has been used to determine the optical band gap, which has been found to vary between 2.25 and 2.9 eV depending on the length of the PEG chains and the chemical nature of the dopant anion, and to detect polaron ¿ bipolaron transitions between band gap states. The two graft copolymers have been found to be excellent cellular matrices, their behavior being remarkably better than that found for other biocompatible polythiophene derivatives [e.g. poly(3,4-ethylenedioxythiophene)]. This is fully consistent with the hydrophilicity of the copolymers, which increases with the molecular weight of the PEG chains, and the molecular organization predicted by atomistic molecular dynamics simulations. Graft copolymers tethered to the surface tend to form biphasic structures in solvated environments (i.e. extended PTh and PEG fragments are perpendicular and parallel to the surface, respectively) while they collapse onto the surface in desolvated environments. Furthermore, the electrochemical activity and the maximum of current density are remarkably higher for samples coated with cells than for uncoated samples, suggesting multiple biotechnological applications in which the transmission with cells is carried out at the electrochemical level.

  • Access to the full text
    Sensitive thermal transitions of nanoscale polymer samples using the bimetallic effect: Application to ultra-thin polythiophene  Open access

     Ahumada Heredero, Óscar; Perez Madrigal, Maria Del Mar; Ramírez García, Jorge; Curcó Cantarell, David; Esteves, Carina; Armelin Diggroc, Elaine; Luongo, Giovanni; Puiggali Bellalta, Jorge; Aleman Llanso, Carlos Enrique; Salvador Matar, Antonio
    Review of scientific instruments
    Date of publication: 2013-06-15
    Journal article

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    A sensitive nanocalorimetric technology based on microcantilever sensors is presented. The tech- nology, which combines very short response times with very small sample consumption, uses the bimetallic effect to detect thermal transitions. Specifically, abrupt variations in the Young¿s modu- lus and the thermal expansion coefficient produced by temperature changes have been employed to detect thermodynamic transitions. The technology has been used to determine the glass transition of poly(3-thiophene methyl acetate), a soluble semiconducting polymer with different nanotechno- logical applications. The glass transition temperature determined using microcantilevers coated with ultra-thin films of mass = 10 - 13 gis5.2 ¿ C higher than that obtained using a conventional differential scanning calorimeter for bulk powder samples of mass = 5 × 10 - 3 g. Atomistic molecular dynamics simulations on models that represent the bulk powder and the ultra-thin films have been carried out to provide understanding and rationalization of this feature. Simulations indicate that the film-air in- terface plays a crucial role in films with very small thickness, affecting both the organization of the molecular chains and the response of the molecules against the temperature.

    A sensitive nanocalorimetric technology based on microcantilever sensors is presented. The tech- nology, which combines very short response times with very small sample consumption, uses the bimetallic effect to detect thermal transitions. Specifically, abrupt variations in the Young’s modu- lus and the thermal expansion coefficient produced by temperature changes have been employed to detect thermodynamic transitions. The technology has been used to determine the glass transition of poly(3-thiophene methyl acetate), a soluble semiconducting polymer with different nanotechno- logical applications. The glass transition temperature determined using microcantilevers coated with ultra-thin films of mass = 10 − 13 gis5.2 ◦ C higher than that obtained using a conventional differential scanning calorimeter for bulk powder samples of mass = 5 × 10 − 3 g. Atomistic molecular dynamics simulations on models that represent the bulk powder and the ultra-thin films have been carried out to provide understanding and rationalization of this feature. Simulations indicate that the film-air in- terface plays a crucial role in films with very small thickness, affecting both the organization of the molecular chains and the response of the molecules against the temperature.

  • Access to the full text
    Modeling biominerals formed by apatites and DNA  Open access

     Revilla Lopez, Guillermo; Casanovas, Jordi; Bertran Cànovas, Oscar; Turon, Pau; Puiggali Bellalta, Jorge; Aleman Llanso, Carlos Enrique
    Biointerphases: an open access journal for the biomaterials interface community
    Date of publication: 2013-04-08
    Journal article

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    Different aspects of biominerals formed by apatite and DNA have been investigated using computer modeling tools. Firstly, the structure and stability of biominerals in which DNA molecules are embedded into hydroxyapatite and fluoroapatite nanopores have been examined by combining different molecular mechanics methods. After this, the early processes in the nucleation of hydroxyapatite at a DNA template have been investigated using molecular dynamics simulations. Results indicate that duplexes of DNA adopting a B double helix can be encapsulated inside nanopores of hydroxyapatite without undergoing significant distortions in the inter-strand hydrogen bonds and the intra-strand stacking. This ability of hydroxyapatite is practically independent of the DNA sequence, which has been attributed to the stabilizing role of the interactions between the calcium atoms of the mineral and the phosphate groups of the biomolecule. In contrast, the fluorine atoms of fluoroapatite induce pronounced structural distortions in the double helix when embedded in a pore of the same dimensions, resulting in the loss of its most relevant characteristics. On the other hand, molecular dynamics simulations have allowed us to observe the formation of calcium phosphate clusters at the surface of the B-DNA template. Electrostatic interactions between the phosphate groups of DNA and Ca 2+ have been found to essential for the formation of stable ion complexes, which were the starting point of calcium phosphate clusters by incorporating PO34 from the solution

  • Polypyrrole derivatives as solvent vapor sensors

     Aradilla Zapata, David; Estrany Coda, Francisco; Aleman Llanso, Carlos Enrique
    RSC Advances
    Date of publication: 2013-09
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Quantum mechanical calculations have been carried out to investigate the affinity of polypyrrole (PPy) and poly[N-(2-cyanoethyl)pyrrole] (PNCEPy) towards molecules from vapors of different solvents (i.e. water, methanol, acetonitrile and chloroform). Results show that neutral cyano-containing polymers interact more favorably with both water and methanol than neutral PPy, whereas these affinities are the opposite for materials in the oxidized state. Moreover, addition of the geometric distortion contributions and the thermodynamic corrections to the interaction energies allow us to conclude that the binding affinities between the two neutral polymers and small polar molecules in the vapor phase are similar, in excellent agreement with experimental information. On the other hand, the affinity of the two conducting polymers towards chloroform is relatively poor independently of the oxidation state, while acetonitrile interacts more favorably with the N¿H of PPy than with the cyano group. The influence of both the vapor molecules and the solvent on the geometric parameters (i.e. dihedral angles, inter-ring bond lengths and bond length alternation pattern) and electronic properties (i.e. ionization potential and p¿p* lowest transition energy) have been evaluated using different approaches, which include time-dependent density functional theory calculations.

  • Hybrid materials consisting of an all-conjugated polythiophene backbone and grafted hydrophilic poly(ethylene glycol) chains

     Bendrea, Anca Dana; Fabregat Jove, Georgina; Cianga, Luminita; Estrany Coda, Francisco; Del Valle Mendoza, Luis Javier; Cianga, Ioan; Aleman Llanso, Carlos Enrique
    Polymer Chemistry
    Date of publication: 2013-03-01
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Organic hybrid materials consisting of an all-conjugated polythiophene backbone and well-defined poly(ethylene glycol) (PEG) grafted chains have been prepared by anodic polymerization of chemically synthesized macromonomers. The latter consist of a pentathiophene sequence in which the central ring bears a PEG chain with Mw = 1000 or 2000 at the 3-position. The influence of the polymerization potential, the length of the PEG branches and the dopant agent on the structure and properties of the graft copolymers has been examined. The chemical structure of the grafted materials has been corroborated by FTIR and X-ray photoelectron spectroscopies. Scanning electron microscopy and atomic force microscopy studies reveal that the morphology and topography of these materials are influenced by the above mentioned factors, even though homogeneous films showing a compact distribution of nanoaggregates, very flat surfaces (i.e. roughness < 15 Å) and nanometric thickness (i.e. 100¿500 nm) were obtained in all cases. Cyclic voltammetry assays have been used to determine the presence of charged species, the electroactivity, the electrostability and the formation of cross-links. The electrochemical stability of the copolymer with grafted PEG chains of Mw = 1000 has been found to increase with the number of consecutive oxidation¿reduction cycles (self-electrostabilizing behavior). Finally, a preliminary investigation into the applicability of these hybrid materials as active surfaces for the selective adsorption of proteins is presented.

  • A synergistic combination of tetraethylorthosilicate and multiphosphonic acid offers excellent corrosion protection to AA1100 aluminum alloy

     Dalmoro, Viviane; dos Santos, João Henrique Zimnoch; Armelin Diggroc, Elaine; Aleman Llanso, Carlos Enrique; Azambuja, Denise S.
    Applied surface science
    Date of publication: 2013-05-15
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    This work describes a new mechanism for the incorporation of organophosphonic acid into silane self-assembly monolayers, which has been used to protect AA1100 aluminum alloy. The protection improvement has been attributed to the fact that phosphonic structures promote the formation of strongly bonded and densely packed monolayer films, which show higher surface coverage and better adhesion than conventional silane systems. In order to evaluate the linking chemistry offered by phosphonic groups, two functionalized organophosphonic groups have been employed, 1,2-diaminoethanetetrakis methylenephosphonic acid (EDTPO) and aminotrimethylenephosphonic acid (ATMP), and combined with tetraethylorthosilicate (TEOS) films prepared by sol¿gel synthesis. Results suggest that phosphonic acids may interact with the surface through a monodentate and bidentate coordination mode and, in addition, form one or more strong and stable linkages with silicon through non-hydrolysable bonds. Therefore, the incorporation of a very low concentration of phosphonic acids on TEOS solutions favors the complete coverage of the aluminum substrate during the silanization process, which is not possible using TEOS alone. The linking capacity of phosphonic acid has been investigated by FTIR-RA spectroscopy, SEM and EDX analysis, X-ray photoelectron spectroscopy (XPS), and quantum mechanical calculations. Finally, electrochemical impedance spectroscopy has been used to study the corrosion protection revealing that EDTPO-containing films afforded more protection to the AA1100 substrate than ATMP-containing films.

  • Computer simulation of fifth generation dendronized polymers: impact of charge on internal organization

     Bertran Cànovas, Oscar; Zhang, Baozhong; Schlüter, A. Dieter; Kröger, Martin; Aleman Llanso, Carlos Enrique
    Journal of physical chemistry B
    Date of publication: 2013-05-16
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    The internal organization of a fifth-generation dendronized polymer (PG5) has been investigated by atomistic molecular dynamics simulations in a vacuum. This study reveals an exceptional behavior of PG5 within the homologous series of g-generation PGg polymers. Three molecular configurations, which present a heterogeneous distribution of dendrons and an amount of backfolding lower than PG4 and PG6, have been obtained for PG5. The highest stability and closest agreement with available experimental data corresponds to a helical conformation characterized by a pitch of about 30 A, thickness of 105 A, and average density of 0.861 g/cm3. While small angle neutron scattering studies of PG5 in solution show a constant radial density distribution around the backbone, we here in our vacuum studies find a cylindrical volume element of sharply reduced density reminiscent of a pore. This neutral PG5 was compared with its charged deprotected analogue, dePG5 in water, to see in as much the positive charges in the periphery of this macromolecule would affect its conformational behavior. During deprotection of PG5, the tert-butyloxycarbonyl protected amine groups are converted into ammonium, mimicking the experimental situation during a divergent synthesis procedure. The repulsive interactions among the positively charged ammonium groups are responsible for a huge (30%) reduction of the average density and a small (1%) increase of elongation of the helical backbone, which results in a structure with a spongy appearance. Also here, we find a reduced dendron density near the backbone which is compensated for by the pore being filled with water. 2013 American Chemical Society

  • Determination of new Cu+, Cu2+, and Zn2+ Lennard-Jones ion parameters in acetonitrile

     Torras Costa, Juan; Aleman Llanso, Carlos Enrique
    Journal of physical chemistry B
    Date of publication: 2013-08-14
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    We present new Lennard-Jones (LJ) parameters for Cu+, Cu2+, and Zn2+ ion-acetonitrile interactions. The adjustment of ion parameters is made to reproduce simultaneously experimental solvation free energy and structural properties, namely ion¿N distance and coordination numbers. Initially, the methodology has been validated deriving parameters for well-studied Na+ and Cl¿ ions in acetonitrile being compared with experimental and theoretical data. The transferability of parameters is checked by the calculation of thermodynamic and structural properties with three different acetonitrile models. The results obtained for transition metal ions show an overall agreement with reference values. The solvation free energy calculated with new LJ trained parameters using a six-site acetonitrile model, and two older three- and six-site acetonitrile models presents, respectively, percent differences of 0.4, 4.8, and 7.3% when compared with experimental values.

  • Amphiphilic polythiophenes- A multifunctional biomedical platform

     Bendrea, Anca-Dana; Cianga, Luminita; Fabregat Jove, Georgina; Del Valle Mendoza, Luis Javier; Aleman Llanso, Carlos Enrique; Timur, Suna; Cianga, Ioan
    Conference on Colloid and Surface Chemistry
    Presentation's date: 2013-05-09
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Computer simulation of dendronized polymers: organization and characterization at the atomistic level

     Bertran Cànovas, Oscar; Zhang, Baozhong; Schlüter, A. Dieter; Halperin, Avraham; Kröger, Martin; Aleman Llanso, Carlos Enrique
    RSC Advances
    Date of publication: 2013
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Sequence dependence of C-end rule peptides in binding and activation of neuropilin-1 receptor

     Zanuy Gomara, David; Kotla, Rohith; Nussinov, Ruth; Teesalu, Tambet; Sugahara, Kazuki N.; Aleman Llanso, Carlos Enrique; Haspel, Nurit
    Journal of structural biology
    Date of publication: 2013-02-24
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Neuropilin-1 (NRP-1) is a hub receptor that plays an essential role in angiogenesis and vascular perme- ability. It is over-expres sed in the new blood vessels grown by tumor cells and is a target for anti-tumor treatment s. Peptides that expose the consensus sequence R/K/ XX R/K at the C-terminus ( C-end rule or CendR peptides) bind to NRP-1 and are internalized into the cell. We used peptide phage display binding assays and molecular dynamics (MD) simulations to study the potential role of the central residues of CendR peptides in binding and activa tion of the NRP-1 receptor. The high stability of RPAR–receptor domain complex stems from the formation of a characteristic pattern of three hydrogen bonds between the peptide C-terminus and the residues in the NRP-1 loop III. Any changes in the peptide structure that fail to preserve this triad result in a less-stable complex. We performed a systematic study of R XX R mutants, where X = A/D/S/R/P, in order to test the effect of replacement of A or P on the binding capabil- ities. Our results, both experimental and computational, show that RRAR, RDAR, RPDR, RPRR and RPPR are capable of binding NRP-1. However, only RPPR and RPRR segments form an optimal organization around loop III with low potential energy. In other analogs, the absence of these stabilizing interactions always results in higher potential energy of the complexes. The binding of RPAR analogs does not guarantee receptor activation; only stable complexes that are properly stabilized via loop III appear able to trigger NRP-1 activati on

  • Conducting polymers obtained from quiescent and stirred solutions: Effects on the properties

     Sanchez Jimenez, Margarita; Aleman Llanso, Carlos Enrique; Estrany Coda, Francisco
    Polymer Engineering & Science Journal
    Date of publication: 2013
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Poly(3,4-ethylenedioxythiophene), poly(N-methylpyr- role), and three-layered systems made of alternated layers of such two conducting polymers have been prepared by agitating the generation solution through a magnetic bar at a stirring speed of 400 rpm. The influence of these controlled dynamic conditions on both the electrochemical behavior and the superficial morphology has been examined. Results indicate that the increase in transport rate of reactants slightly favors the generation of more polymer weight at equal charge consumed. Consequently, the thickness of the materials prepared under stirring increases consider- ably with respect to those obtained from quiescent solutions, systems prepared using short (100 s) and large (300 s) polymerization times changing from nano- metric to submicrometric and from submicrometric to micrometric length-scales, respectively. Moreover, the porosity of PNMPy and PEDOT films also increases upon agitation. Thus, quiescent solutions produce compact and cavernous morphologies, respectively, for these materials, whereas the PNMPy and PEDOT obtained from agitated solutions are globular and spongy, respectively. Finally, the electroactivity, elec- trochemical stability, and electrical conductivity of the materials obtained from stirred solutions have been found to be significantly higher than those of the poly- mers prepared using quiescent solutions.

  • Nanometric ultracapacitors fabricated using multilayer of conducting polymers on self-assembled octanethiol monolayers

     Aradilla Zapata, David; Perez Madrigal, Maria Del Mar; Estrany Coda, Francisco; Azambuja, Denise S.; Iribarren Laco, Jose Ignacio; Aleman Llanso, Carlos Enrique
    Organic electronics
    Date of publication: 2013-06
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Symmetric ultracapacitors have been fabricated considering nanometric 3-layered films made of alternated layers of poly(3,4-ethylenedioxythiophene) (external and internal layers) and polypyrrole (intermediate layer) deposited on steel uncoated and coated with octanethiol self-assembled monolayer. The highest electrochemical and capacitance parameters (i.e. electroactivity, doping level, stored charge, specific capacitance, Coulomb efficiency, energy density and power density) correspond to the ultracapacitor derived from the assembly of 3-layered films deposited on pre-treated steel. Thus, the interface separating the octanethiol monolayer and the most internal layer of the 3-layered film produces a very favorable interaction, which promotes important electrochemical benefits similar to those found for the interfaces in conventional multilayered films. Moreover, the pre-treatment of the steel electrode enhances the roughness and porosity of the film deposited on it, transmitting this effect layer-by-layer. Structural and morphological characteristics, which have been characterized using scanning electron microscopy and atomic force microscopy, have been related with the electrochemical and capacitance properties of the ultracapacitors.

    Symmetric ultracapacitors have been fabricated considering nanometric 3-layered films made of alternated layers of poly(3,4-ethylenedioxythiophene) (external and internal layers) and polypyrrole (intermediate layer) deposited on steel uncoated and coated with octanethiol self-assembled monolayer. The highest electrochemical and capacitance parameters (i.e. electroactivity, doping level, stored charge, specific capacitance, Coulomb efficiency, energy density and power density) correspond to the ultracapacitor derived from the assembly of 3-layered films deposited on pre-treated steel. Thus, the interface separating the octanethiol monolayer and the most internal layer of the 3-layered film produces a very favorable interaction, which promotes important electrochemical benefits similar to those found for the interfaces in conventional multilayered films. Moreover, the pre-treatment of the steel electrode enhances the roughness and porosity of the film deposited on it, transmitting this effect layer-by-layer. Structural and morphological characteristics, which have been characterized using scanning electron microscopy and atomic force microscopy, have been related with the electrochemical and capacitance properties of the ultracapacitors.

  • Resolving the subnanometric structure of ultrathin films of poly(3,4-ethylenedioxythiophene) on steel surfaces: A molecular modeling approach

     Zanuy Gomara, David; Aleman Llanso, Carlos Enrique
    Soft matter
    Date of publication: 2013-12-28
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Poly(3,4-ethylenedioxythiophene), abbreviated PEDOT, is one of the most outstanding electroactive polymers, whose applications cover a wide range of fields from biomedicine to electronic components. In this work the physicochemical properties of nanoconstructs obtained by growing PEDOT chains over steel surfaces are investigated. The structural features of such nanostructures, which had successfully been used to build supercapacitors, are investigated, revealing that the polymeric phase plays a key role in the charge accumulation process. The ultra-structure organization and dynamics of these constructs are explored by molecular simulations and the results are compared with the available experimental data. The outcome of this investigation has offered a detailed vision of the structural features that lead to an extraordinarily efficient charge accumulation. Atomistic models generated using stochastic methods had provided different distributions of polymer chains over a metallic surface. Molecular dynamics simulations performed on such models have demonstrated that the extraordinary capacity for charge accumulation stems from a thin balance between the electrostatic repulsion that polymer chains exercise to each other and the attraction that the counterions present in the electropolymerization exert on those oxidized PEDOT chains. This situation favors the aggregation of the PEDOT chains mediated by the perchlorate ions, which act over them as inter-chain cement and which leads to regular three dimensional organization of chains, regardless of their initial distribution over the metallic surface. At the same time, such inner proximity of the polymer chains when growing upwards forces the capture of perchlorate ions, acting as accumulated charges that could be further released if the PEDOT oxidation state is externally reversed.

  • Novel epoxy coating based on DMSO as a green solvent, reducing drastically the volatile organic compound content and using conducting polymers as a nontoxic anticorrosive pigment

     Martí Barroso, Mireia; Molina Pérez, Laura; Aleman Llanso, Carlos Enrique; Armelin Diggroc, Elaine
    ACS Sustainable Chemistry & Engineering
    Date of publication: 2013-12-02
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    This work reports novel anticorrosive epoxy coatings based on safer dimethyl sulfoxide solvent and free of zinc anticorrosive pigment. The latter was replaced by conducting polymers, as nontoxic anticorrosive pigments. The procedure used for their formulation, spectroscopic characterization, thermal and mechanical properties have been discussed and compared with those of conventional epoxy coatings. Furthermore, accelerated and long-term corrosion assays have evidenced that the new epoxy coatings protect steel from chlorine aggressive medium for 2880 h and for 2 years in atmospheric corrosive medium. Therefore, the results evidenced an excellent corrosion resistance, excellent application, and aesthetic appearance of the new coatings. © 2013 American Chemical Society.

  • Atomistic organization and characterization of tube-like assemblies comprising peptide-polymer conjugates: computer simulation studies

     Bertran Cànovas, Oscar; Curcó Cantarell, David; Zanuy Gomara, David; Aleman Llanso, Carlos Enrique
    FARADAY DISCUSSIONS
    Date of publication: 2013
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    The structure and stability of the nanotube obtained by assembling peptide-polymer conjugates consisting of two poly(n-butyl acrylate) blocks coupled to the cyclic (D-alt-L)-octapeptide cyc[(L-Gln-D-Ala-L-Lys-D-Ala)(2)], have been investigated at the molecular level using atomistic molecular dynamics simulations. The effect of the wrapping polymer shells in the tube-like core, which consists of stacked beta-sheet cyclopeptides, has been examined by simulating assemblies of both unsubstituted cyclopeptides, and conjugates in chloroform and N,N-dimethylformamide solutions. Furthermore, the influence of the environment has been investigated by comparing conjugate assemblies in solution with those deposited on mica. In addition, nanotubes stabilized by beta-sheet-like hydrogen bonds between both parallel and antiparallel oriented cyclopeptides have been considered in all cases. The results, which have been analysed in terms of energy contributions, partial radial distribution functions, inter-subunit distances, shape of the cyclopeptide ring, internal van der Waals diameters, and both height and width of the nanostructures deposited on mica, have provided important microscopic insights. For example, analysis of both the energy terms and the structural dynamics obtained for the different assemblies indicate that the mica surface interacts more favourably with the parallel assembly than with the antiparallel ones, whereas the only configuration that is structurally stable in solution is the latter. Furthermore, adsorption onto the solid substrate produces a small deformation of the cylindrical molecular system.

  • Transport of hydronium ions inside poly(styrene-co-divinyl benzene) cation exchange membranes

     Cordova Mateo, Ester; Bertran Cànovas, Oscar; Ferreira, Carlos Arthur; Aleman Llanso, Carlos Enrique
    Journal of membrane science
    Date of publication: 2013-02-01
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Bioactive nanomembranes of semiconductor polythiophene and thermoplastic polyurethane: Thermal, nanostructural and nanomechanical properties

     Perez Madrigal, Maria Del Mar; Giannotti, Marina I.; Oncins Marco, Gerard; Franco Garcia, Maria Lourdes; Armelin Diggroc, Elaine; Puiggali Bellalta, Jorge; Sanz Carrasco, Fausto; Del Valle Mendoza, Luis Javier; Aleman Llanso, Carlos Enrique
    Polymer Chemistry
    Date of publication: 2013-02-07
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Engineering strategy to improve peptide analogs: from structure-based computational design to tumor homing

     Zanuy Gomara, David; Sayago García, Francisco Javier; Revilla Lopez, Guillermo; Ballano Ballano, María Gema; Agemy, Lilach; Kotamraju, Venkata Ramana; Jimenez, Ana I.; Cativiela, Carlos; Nussinov, Ruth; Sawvel, April M.; Ruoslahti, Erkki; Stucky, Galen; Aleman Llanso, Carlos Enrique
    Journal of computer-aided molecular design
    Date of publication: 2013-01
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    We present a chemical strategy to engineer analogs of the tumor-homing peptide CREKA (Cys-Arg-Glu-Lys-Ala), which binds to fibrin and fibrin-associated clotted plasma proteins in tumor vessels (Simberg et al. in Proc Natl Acad Sci USA 104:932-936, 2007) with improved ability to inhibit tumor growth. Computer modeling using a combination of simulated annealing and molecular dynamics were carried out to design targeted replacements aimed at enhancing the stability of the bioactive conformation of CREKA. Because this conformation presents a pocket-like shape with the charged groups of Arg, Glu and Lys pointing outward, non-proteinogenic amino acids alpha-methyl and N-methyl derivatives of Arg, Glu and Lys were selected, rationally designed and incorporated into CREKA analogs. The stabilization of the bioactive conformation predicted by the modeling for the different CREKA analogs matched the tumor fluorescence results, with tumor accumulation increasing with stabilization.

  • Synergy of the I-/I-3(-) redox pair in the capacitive properties of nanometric poly(3,4-ethylenedioxythiophene)

     Aradilla Zapata, David; Estrany Coda, Francisco; Aleman Llanso, Carlos Enrique
    Organic electronics
    Date of publication: 2013-01
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Revestimientos a base de sílica e ácido fosfônico para proteção anticorrosiva da liga de alumínio AA2024-T3

     Dalmoro, Viviane
    Defense's date: 2013-11-04
    Universitat Politècnica de Catalunya
    Theses

     Share Reference managers Reference managers Open in new window

  • Design, synthesis, characterization and development of novel organic conducting polymers with technological applications  Open access

     Aradilla Zapata, David
    Defense's date: 2013-01-11
    Department of Chemical Engineering, Universitat Politècnica de Catalunya
    Theses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    In this thesis, a series of novel organic conducting polymers have been synthesized using alternative methods based on electrochemical techniques, which have allowed to broaden the knowledge in the field of the characterization by means of topological, spectroscopic, electrochemical and structural techniques. Among the variety of synthesis techniques of conducting polymers, layer-by-layer (LbL) has been one of the most important to build multilayered systems. Thus, in this thesis the LbL has shown to be an excellent procedure to explore new applications in the field of energy storage using conducting polymers. On the other hand, recently, the influence of new sustituents on functionalized conducting polymers has been proved to modify the structural, optical and physical properties of conducting polymers. Within this context, synthesis of novel functionalized conducting polymers bearing strong electron-withdrawing sustituents such as cyano group or halide atoms have been widely studied and characterized throughout this thesis. The presence of these substituents have emerged as promising candidates in the field of chemical sensors and electrochromic devices. Although the functionality of polymers or the development of new techniques are excellent procedures to synthesize and to develop new properties on the field of conducting polymers, it is worth mentioning that the substrate plays a crucial role on the electrochemical field. Accordingly, the substrates can also modify and change the properties of conducting polymers during the electropolymerization process. In this way, different substrates were employed in this work with the aim of achieving new applications in the field of corrosion inhibitors and as supercapacitors. Supercapacitors as energy storage device has been an outstanding application during this thesis. Thus, the field of nanotechnology has taken an important part in this thesis through development and design of promising hybrid nanocomposites based on conducting polymers and clay with technological applications and interesting optoelectronic properties. The contribution of theoretical techniques based on quantum mechanical calculations have allowed to predict some electronic and structural properties of conjugated polymers, which could be corroborated experimentally. The quantum mechanics is a useful tool to check experimental results and to understand mechanisms not fully understood at experimental level. Therefore, theoretical calculations have provided promising information to obtain new insights in the field of conducting polymers.

    La presente tesis se encuentra focalizada en el estudio de nuevos polímeros conductores orgánicos obtenidos a partir de métodos alternativos basados en principios electroquímicos. Entre los principales métodos de polimerización la técnica conocida como capa-a-capa ha emergido con gran fuerza en los últimos años dada sus numerosas ventajas y propiedades. En este contexto, la síntesis de polímeros conductores mediante este procedimiento permitió comprender y analizar el efecto sinérgico entre capas, consiguientemente la caracterización de estos nuevos materiales a partir de técnicas estructurales, espectroscópicas, morfológicas, electroquímicas y ópticas permitió indagar y desarrollar aplicaciones en diferentes campos tecnológicos tales como la electrónica o la corrosión. Otro de los factores que influyen en las propiedades de los polímeros conductores es el proceso de funcionalización. En esta tesis, la incorporación de grupos funcionales con elevado carácter aceptor de electrones centró una parte importante del trabajo, de este modo, los polímeros conductores funcionalizados con átomos halogenados o mediante el grupo ciano evidenciaron una gran influencia en las propiedades físicas, estructurales, ópticas y morfológicas de las estructuras químicas en tiofeno y pirrol. La modificación de determinadas propiedades en estos polímeros permitió desarrollar componentes basados en sensores químicos o dispositivos electrocrómicos. Acorde a esta temática, la modificación de la superficie juega también un papel importante y crucial en las propiedades de los polímeros conductores durante el proceso de síntesis electroquímica. Análogamente al caso de la funcionalización el estudio de la modificación de la superficie denotó una gran expectativa en el desarrollo de nuevos supercondensadores orgánicos, así como una gran alternativa para aplicación como inhibidores de corrosión. Finalmente, en el ámbito experimental de esta tesis, se han orientado estudios en el campo de la nanotecnología en la síntesis y caracterización de nuevos materiales híbridos nanocompuestos con interesantes propiedades optoelectrónicas y electroquímicas. A nivel teórico, la contribución de cálculos teóricos basados en mecánica quántica permitieron predecir determinadas propiedades electrónicas y estructurales de polímeros conductores, cuyos valores fueron corroborados experimentalmente. Así, la química teórica proporcionó un amplio conocimiento en la exploración y comprensión de los mecanismos estructurales de los polímeros conductores.

  • Membranas Poliméricas Íon Seletivas Aniônicas e Catiônicas Para Uso Em Eletrodiálise

     Müller, Franciélli
    Defense's date: 2013-09-27
    Universitat Politècnica de Catalunya
    Theses

     Share Reference managers Reference managers Open in new window

  • Formulation of anticorrosive paints employing conducting polymers  Open access

     Martí Barroso, Mireia
    Defense's date: 2013-07-08
    Universitat Politècnica de Catalunya
    Theses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    The intention and purpose of the present thesis is to prepare a series of protective coatings using some conducting polymers (CPs) as corrosion inhibitors. The use of organic paints is the most common method for corrosion prevention. Anticorrosive coatings form a class of high-performance systems with a very wide range of applications and being classified in two broad groups: heavy-duty coatings, for high performance, and light-duty coatings, for medium performance. The first class being required for highly aggressive medium, like oil platforms, bridges, chemical industry plants, containers, shipping, and others; the late being employed mainly for outside industrial environments, urban environments, houses, offices, and others. This thesis consists of an overview and a compendium of the following work stages and results: 1. Preparation of nanostructured CPs for corrosion inhibition: Study of the ability of poly(N-methylpyrrole) to form nanostructures and the performance of such nanostructures when act as anticorrosive additive of organic coatings. 2. Partial replacement of metallic zinc dust usually employed in heavy duty protective coatings, by a small concentration of CPs: Study of the use of a small amount of polyaniline emeraldine salt as a partial substitute of metallic zinc dust in marine epoxy primers in order to maintain corrosion inhibition. 3. Evaluation of an environmentally friendly anticorrosive pigment for alkyd priming: Study of the substitution of a high concentration of zinc phosphate, commonly employed in light-duty coatings, by a very low concentration of polyaniline emeraldine base (undoped form), polyaniline emeraldine salt (doped form) and an eco-friendly polythiophene derivative (partially oxidized) in an alkyd coatings and the study of their protective performance using accelerated corrosion assays. 4. Preparation of a novel epoxy coating, based on DMSO as green solvent and free of zinc anticorrosive pigment, and its application on carbon steel protection: Formulation and evaluation of a novel anticorrosive epoxy coating based on DMSO solvent and free of zinc, using polyaniline emeraldine base and poly[2,2’-(3-methylacetate)thiophene] as anticorrosive pigments. All the results derived from the present thesis have been accepted or have been sent for publication in international journals and also reported in some international congresses, as we point below: 1. M. Martí, G. Fabregat, F. Estrany, C. Alemán, E. Armelin, “Nanostructured conducting polymer for dopamine detection”, J.Mater. Chem., 2010, 20, 10652-10660. 2. E. Armelin, M. Martí, F. Liesa, J.I. Iribarren, C. Alemán, “Partial replacement of metallic zinc dust in heavy duty protective coatings by conducting polymer”, Prog. Org. Coat., 2010, 69, 26-30. 3. M. Martí, G. Fabregat, D.S. Azambuja, C. Alemán, E. Armelin, “Evaluation of an environmentally friendly anticorrosive pigment for alkyd primer”, Prog. Org. Coat., 2012, 73, 321–329. 4. M. Martí, L. Molina, C. Alemán, E. Armelin, “Replacement of toxic solvents and anticorrosive pigments used in solvent-borne epoxy coatings by safer functional organic compounds”, submitted for publication in Journal of Hazardous Materials, 2013. 5. M. Martí, E. Armelin, J. Iribarren, C. Alemán. Soluble polythiophenes as anticorrosive additives for marine epoxy paints”, submitted for publication in Materials and Corrosion, 2013. 6. G. Fabregat, M. Martí, F. Estrany, C. Alemán, E. Armelin, “Nanostructured Poly(N-Methylpyrrole) and Its Application in Dopamine Detection”, E-MRS 2010 Spring Meeting. 2010, Strasbourg, France. 7. E. Armelin, M. Martí, F. Estrany, C. Alemán, “Environmentally friendly anticorrosive additive to replace zinc and its compounds in alkyd and epoxy primers”, 12th Mediterranean Congress of Chemical Engineering: shaping the future of chemical engineering. 2011, Barcelona, Spain

    El propósito de la presente tesis es preparar una serie de recubrimientos protectores empleando polímeros conductores (CPs) como inhibidores de la corrosión. El uso de pinturas orgánicas es el método más empleado para la prevención de la corrosión. Los recubrimientos anticorrosivos forman una clase de sistemas de alto rendimiento con una amplia variedad de aplicaciones y pueden ser clasificados en dos grandes grupos: recubrimientos de altas prestaciones y recubrimientos de suaves prestaciones. El primero de ellos es el que se emplea en estructuras expuestas a ambientes muy agresivos, tales como: plataformas petrolíferas, puentes, plantas industriales químicas, contenedores, barcos, entre otros; y el último es el que se suele emplear en el exterior de ambientes industriales, ambientes urbanos, casas, oficinas, entre otros. La presente tesis consiste en un compendio de las siguientes etapas del trabajo y resultados: 1. Preparación de CPs nanoestructurados para inhibición de la corrosión: Estudio de la habilidad del Poli(N-metilpirrol) para formar estructuras nanoestructuradas y la actuación de éstas como aditivo anticorrosivo en recubrimientos orgánicos. 2. Sustitución parcial del zinc metálico en polvo habitualmente empleado en pinturas de altas prestaciones, por una pequeña cantidad de CP: Estudio del uso de pequeñas concentraciones de polianilina sal emeraldina (PAni-EB), como sustituto parcial del zinc metálico en polvo, en pinturas de imprimación epoxi marinas, con el objetivo de mantener la inhibición a la corrosión. 3. Evaluación de pigmentos anticorrosivos amigables con el medio ambiente para pinturas de imprimación alquídicas: Estudio de la sustitución de una elevada concentración de fosfato de zinc, generalmente empleado en recubrimientos de suaves prestaciones, por una concentración muy baja de PAni-EB (forma no-dopada), PAni-ES (forma dopada) y un derivado del politiofeno (parcialmente dopado) en un recubrimiento alquídico, y el estudio de sus capacidades protectoras empleando ensayos de corrosión acelerados. 4. Preparación de una nueva pintura epoxi, basada en DMSO como disolvente ecológico y libre de pigmento anticorrosivo de zinc, y su aplicación para la protección de acero al carbono: Formulación y evaluación de una nueva pintura epoxi basada en DMSO como solvente y empleando PAni-EB y poli[2, 2’-(3-metilacetato)tiofeno] como nuevos pigmentos anticorrosivos. Todos los resultados obtenidos en la presente tesis han sido aceptados o han sido enviados para publicación en revistas internacionales; además, algunos resultados han sido divulgados recientemente en congresos internacionales, tal y como se describe abajo: 1. M. Martí, G. Fabregat, F. Estrany, C. Alemán, E. Armelin, “Nanostructured conducting polymer for dopamine detection”, J. Mater. Chem., 2010, 20, 10652-10660. 2. E. Armelin, M. Martí, F. Liesa, J.I. Iribarren, C. Alemán, “Partial replacement of metallic zinc dust in heavy duty protective coatings by conducting polymer”, Prog. Org. Coat., 2010, 69, 26-30. 3. M. Martí, G. Fabregat, D.S. Azambuja, C. Alemán, E. Armelin, “Evaluation of an environmentally friendly anticorrosive pigment for alkyd primer”, Prog. Org. Coat., 2012, 73, 321–329. 4. M. Martí, L. Molina, C. Alemán, E. Armelin, “Replacement of toxic solvents and anticorrosive pigments used in solvent-borne epoxy coatings by safer functional organic compounds”, enviado para publicación en Journal of Hazardous Materials, 2013. 5. M. Martí, E. Armelin, J. Iribarren, C. Alemán. Soluble polythiophenes as anticorrosive additives for marine epoxy paints”, enviado para publicación en Materials and Corrosion, 2013. 6. G. Fabregat, M. Martí, F. Estrany, C. Alemán, E. Armelin, E-MRS 2010 Spring Meeting. 2010, Strasbourg, France. 7. E. Armelin, M. Martí, F. Estrany, C. Alemán, 12th Mediterranean Congress of Chemical Engineering: shaping the future of chemical engineering. 2011, Barcelona, Spain.

  • POLIMEROS CONDUCTORES Y SUS DERIVADOS HIBRIDOS CON APLICACIONES AVANZADAS

     Estrany Coda, Francisco; Armelin Diggroc, Elaine; Zanuy Gomara, David; Iribarren Laco, Jose Ignacio; Sanchez Jimenez, Margarita; Aleman Llanso, Carlos Enrique
    Participation in a competitive project

     Share

  • An electroactive and biologically responsive hybrid conjugate based on chemical similarity

     Fabregat Jove, Georgina; Ballano Ballano, María Gema; Armelin Diggroc, Elaine; Del Valle Mendoza, Luis Javier; Cativiela, Carlos; Aleman Llanso, Carlos Enrique
    Polymer Chemistry
    Date of publication: 2012-11-20
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Synthetic amino acids have become very important tools for the design of new materials. In this work, an electroactive polymer¿amino acid hybrid material has been synthesized by conjugating poly(3,4-ethylenedioxythiophene) (PEDOT), a well known conducting polymer, with a synthetic amino acid bearing 3,4-ethylenedioxythiophene, which has been explicitly designed and prepared for such a purpose. Nanometric films have been electrochemically generated using a two-step procedure to evaluate the properties and potential applications of the resulting hybrid material. The successful incorporation of the amino acid as end-capping of the PEDOT chains has been proved by FTIR, energy dispersive X-ray and X-ray photoelectron spectroscopies. The fabrication of the hybrid material using an engineered tissue has allowed us to preserve not only morphological and structural characteristics of the conducting polymer but also, and most importantly, to preserve the electrical conductivity, electroactivity, electrochemical stability and specific capacitance. Finally, the behavior of the hybrid material as a cellular matrix has been compared with that of PEDOT using cellular adhesion and proliferation assays. Results obtained in this work represent the success of a new strategy for the preparation of peptide-conducting polymer hybrid materials, which is currently being improved upon by transforming the 3,4-ethylenedioxythiophene-containing amino acid into a cell adhesive peptide

  • Factors governing the conformational tendencies of Ca- ethylated a-amino acids: Chirality and side-chain size effects

     Casanovas, Jordi; Revilla Lopez, Guillermo; Crisma, M.; Toniolo, Claudio; Aleman Llanso, Carlos Enrique
    Journal of physical chemistry B
    Date of publication: 2012-11-15
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • New insights into the characterization of poly(3-chlorothiophene) for electrochromic devices

     Aradilla Zapata, David; Casanovas, Jordi; Estrany Coda, Francisco; Iribarren Laco, Jose Ignacio; Aleman Llanso, Carlos Enrique
    Polymer Chemistry
    Date of publication: 2012
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Access to the full text
    Response of crown ether functionalized polythiophenes to alkaline ions  Open access

     Zanuy Gomara, David; Preat, Julien; Perpete, Eric A.; Aleman Llanso, Carlos Enrique
    Journal of physical chemistry B
    Date of publication: 2012-04-19
    Journal article

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    The sensing response of 15-crown-5-ether functionalized polythiophene to Li+, Na+, and K+ has been investigated at the atomistic level using molecular dynamics simulations. The stability associated with all the identified binding sites has been corroborated by quantum mechanical calculations. Although the cavity of the macrocycle is not the most visited binding site, such receptor is responsible of the selective sensing response of this polythiophene derivative. PF6– counterions reduce the mobility of the alkaline cations, which do not occupy the crown ether cavity of consecutive repeating units due to electrostatic repulsions. Furthermore, the relative entropy for the “free state → bound state” has been estimated using a procedure based on the covariance matrix atom-positional fluctuations. Evaluation of the entropic contributions allow us to complete the thermodynamics scenario of binding process, which was recently initiated by calculating the enthalpies at quantum mechanical level [ Chem. Eur. J. 2009, 15, 4676]. Results indicate an entropycally driven binding preference.

  • Bioactive and electroactive response of flexible polythiophene:Polyester nanomembranes for tissue engineering

     Perez Madrigal, Maria Del Mar; Armelin Diggroc, Elaine; Del Valle Mendoza, Luis Javier; Estrany Coda, Francisco; Aleman Llanso, Carlos Enrique
    Polymer Chemistry
    Date of publication: 2012-04
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Properties of oligothiophene dendrimers as a function of molecular architecture and generation number

     Cordova Mateo, Ester; Rodriguez Ropero, Francisco; Bertran Cànovas, Oscar; Aleman Llanso, Carlos Enrique
    Chemphyschem
    Date of publication: 2012-04-10
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Controlling the morphology of poly(N -cyanoethylpyrrole)

     Fabregat Jove, Georgina; Aleman Llanso, Carlos Enrique; Casas Becerra, M. Teresa; Armelin Diggroc, Elaine
    Journal of physical chemistry B
    Date of publication: 2012-04-26
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    The morphology of poly(N-cyanoethylpyrrole) has been controlled through the polymerization process. This polymer has been prepared by anodic polymerization, chemical oxidative polymerization in emulsion medium, and layer-by-layer templating polymerization. Anodic polymerization using LiClO4 as supporting electrolyte provides compact films, in which the oxidation degree is controlled through the thickness, useful for the microdetection of dopamine. Chemical polymerization using FeCl3 as oxidant agent results in very well-defined microspheres with porous internal structure, which may be useful in molecular loading and transport processes. Finally, the layer-by-layer templating technique produces core−shell particles of controlled size and thickness. Moreover, these core−shell particles can be easily converted in hollow microspheres by removing the template

  • Examining the formation of specific interactions between poly(3,4-ethylenedioxythiophene) and nucleotide bases

     Zanuy Gomara, David; da Cruz Teixeira Dias, Bruno José; Del Valle Mendoza, Luis Javier; Poater, Jordi; Solà, Miquel; Aleman Llanso, Carlos Enrique
    RSC Advances
    Date of publication: 2012-12-17
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • New Sulfonated Polystyrene and Styrene¿Ethylene/Butylene¿Styrene Block Copolymers for Applications in Electrodialysis

     Müller, Franciélli; Ferreira, Carlos Arthur; Franco Garcia, Maria Lourdes; Puiggali Bellalta, Jorge; Aleman Llanso, Carlos Enrique; Armelin Diggroc, Elaine
    Journal of physical chemistry B
    Date of publication: 2012-09
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Phosphonic acid/silica-based films: A potential treatment for corrosion protection

     Dalmoro, Viviane; dos Santos, João Henrique Zimnoch; Armelin Diggroc, Elaine; Aleman Llanso, Carlos Enrique; Azambuja, Denise S.
    Corrosion science
    Date of publication: 2012-07
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Films of tetraethyl orthosilicate (TEOS) and 1,2-diaminoethanetetrakis methylenephosphonic acid (EDTPO) were evaluated as a anticorrosive treatment against corrosion for AA2024-T3 in a 0.05 mol L−1 NaCl solution. The electrochemical behavior was investigated using electrochemical impedance spectroscopy. The chemical composition of the silanization bath and films were analyzed by infrared spectroscopy. The effect of hydrolysis time on sol–gel TEOS/EDTPO was monitored, being obtained the best performance after 72 h of hydrolysis at 25 °C. The optimal concentration of EDTPO within the TEOS matrix was 3.75 × 10−4 mol L−1. Improved barrier properties of these films were achieved by the addition of silica nanoparticles.

  • A conducting polymer/protein composite with bactericidal and electroactive properties

     Teixeira Dias, Bruno; Del Valle Mendoza, Luis Javier; Aradilla Zapata, David; Estrany Coda, Francisco; Aleman Llanso, Carlos Enrique
    Macromolecular materials and engineering
    Date of publication: 2012-05
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Dextrin- and conducting-polymer-containing biocomposites: Properties and behavior as cellular matrix

     Teixeira Dias, Bruno; Del Valle Mendoza, Luis Javier; Estrany Coda, Francisco; Mano, J.F.; Reis, Rui Luís; Aleman Llanso, Carlos Enrique
    Macromolecular materials and engineering
    Date of publication: 2012-04
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Preparation and characterization of semiconducting polymeric blends. Photochemical synthesis of poly(3-alkylthiophenes) using host microporous matrices of poly(vinylidene fluoride)

     Gomes, Alex Linardi; Pinto Zakia, Maria Beny; Armelin Diggroc, Elaine; Filho, Jose Godoy; Aleman Llanso, Carlos Enrique; Sinezio De Carvalho Campos, Joao
    Polymer Chemistry
    Date of publication: 2012-05
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Chemical and electrochemical synthesis techniques have been the principal methods of obtaining polymers in industry and scientific research laboratories. However, during the last two decades, photochemical synthesis, although poorly studied, has been reported to present several advantages, in that it is a fast and cheap technique, and it is not aggressive to the environment. The technique has been applied to the production of some conducting polymers. In this study, semiconducting polymeric blends composed of PT3AA-K¿PVDF and PT3MA¿PVDF were respectively obtained by photochemical polymerization in aqueous solutions of 3-thiophene acetic acid and 3-thiophene methyl acetate monomers using PVDF microporous matrices and potassium dichromate as catalyst. The percentage of products and by-products incorporated in the host matrix was obtained by gravimetric analysis. The chemical structures of the polymers synthesized were analyzed by FTIR, UV-vis and 1H NMR. GPC analysis indicated the formation of oligomers composed of 5¿6 mers. The morphology of the matrices and polymeric blends was observed by SEM-EDS and their electric behavior evaluated by measures of electric conductivity. The SEM images show the presence of polythiophene in the pores of the PVDF microporous membrane. The thermal properties of the polymers and their blends were evaluated by DSC and TGA. Thermal analysis by DSC demonstrated an increase in melting temperature of the blends, attributed to the confinement of PVDF crystalline phases for the polymer photosynthesized. The results of volumetric conductivity measurements of polymeric blends show an increase in conductivity in the matrices from 10-15 to 10-11 S cm-1.

  • Hybrid polythiophene-clay exfoliated nanocomposites for ultracapacitor devices

     Aradilla Zapata, David; Azambuja, Denise S.; Estrany Coda, Francisco; Casas Becerra, M. Teresa; Ferreira, Carlos Arthur; Aleman Llanso, Carlos Enrique
    Journal of materials chemistry B
    Date of publication: 2012-06-14
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Exfoliated nanocomposites of poly(3,4-ethylenedioxythiophene) (PEDOT) and montmorillonite (MMT) have been prepared by in situ anodic polymerization, concentrations of clay ranging from 5% w/w to 50% w/w being included in the aqueous polymerization medium. The morphology, electrical conductivity, adherence, thermal stability, charge storage, specific capacitance, electrostability, doping level and band gap have been determined for the different PEDOT–MMT nanocomposites and compared with those of pristine PEDOT. Many of these properties have been found to depend on both the concentration of clay and the thickness (micrometric or nanometric) of the generated films. Types I and II ultracapacitors have been fabricated using nanometric and micrometric films of PEDOT and PEDOT–MMT. The properties of such devices have been characterized and compared with those reported in the literature for ultracapacitors fabricated using nanocomposites of PEDOT and other inorganic materials. Both nanometric and micrometric type II ultracapacitors, which correspond to an asymmetric configuration of PEDOT and PEDOT–MMT films, have been found to present the better properties (e.g. the specific capacitance for nanometric and micrometric devices is 429 and 116 F g 1, respectively), evidencing the favorable effect of the clay. Finally, the effects of the electrochemicaldegradation on the ultracapacitors have been rationalized using electrochemical impedance spectroscopy.

  • Ultraporous poly(3,4-ethylenedioxythiophene) for nanometric electrochemical supercapacitor

     Aradilla Zapata, David; Estrany Coda, Francisco; Armelin Diggroc, Elaine; Aleman Llanso, Carlos Enrique
    Thin solid films
    Date of publication: 2012-04-30
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Evaluation of an environmentally friendly anticorrosive pigment for alkyd primer

     Martí Barroso, Mireia; Fabregat Jove, Georgina; Azambuja, Denise S.; Aleman Llanso, Carlos Enrique; Armelin Diggroc, Elaine
    Progress in organic coatings
    Date of publication: 2012-04
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    An alkyd formulation containing zinc phosphate (10 wt.%) was prepared and subsequently modified replacing the latter anticorrosive additive by a very low concentration of conducting polymer. Specifically, three modified paints, which contain polyaniline emeraldine base (undoped form), polyaniline emeraldine salt (doped form) and an eco-friendly polythiophene derivative (partially oxidized), were formulated. The properties and corrosion resistance of the four alkyd coatings have been characterized. Among the three modified paints, the one containing polythiophene shows the best adherence and the highest corrosion resistance. This has been attributed to the fact that the miscibility of the polythiophene derivative with the alkyd formulation is better than that of polyaniline. Furthermore, accelerated corrosion assays and electrochemical impedance spectroscopy measurements revealed that the corrosion resistance of the paint with polythiophene is several orders of magnitude higher than that with zinc phosphate. The polythiophene derivative has been found to induce the formation of a passivating and well-adhered layer between the coating and the surface, preventing the access of chloride anions and oxygen to the substrate.

  • Stochastic simulation of structural properties of natively unfolded and denatured proteins

     Curcó Cantarell, David; Michaux, Catherine; Roussel, Guillaume; Tinti, Emmanuel; Perpete, Eric A.; Aleman Llanso, Carlos Enrique
    Journal of molecular modeling
    Date of publication: 2012-09
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    A new simulation strategy based on a stochastic process has been developed and tested to study the structural properties of the unfolded state of proteins at the atomistic level. The procedure combines a generation algorithm to produce representative uncorrelated atomistic microstructures and an original relaxation method to minimize repulsive non-bonded interactions. Using this methodology, a set of 14 unfolded proteins, including seven natively unfolded proteins as well as seven “classical” proteins experimentally described in denaturation conditions, has been investigated. Comparisons between the calculated and available experimental values of several properties, at hydrodynamic and atomic level, used to describe the unfolded state, such as the radius of gyration, the maximum length, the hydrodynamic radius, the diffusion coefficient, the sedimentation coefficient, and the NMR chemical shifts, reflect a very good agreement. Furthermore, our results indicate that the relationship between the radius of gyration and the hydrodynamic radius deviates from the Zimm’s theory of polymer dynamics for random coils, as was recently observed using single-molecule fluorescent methods. Simulations reveal that the interactions between atoms separated by three chemical bonds (1–4 interactions) play a crucial role in the generation process, suggesting that the unfolded state is essentially governed

  • Reviewing Extrapolation Procedures of the Electronic Properties on the p-Conjugated Polymer Limit

     Torras Costa, Juan; Casanovas, Jordi; Aleman Llanso, Carlos Enrique
    Journal of physical chemistry A
    Date of publication: 2012-06-19
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Effects of ring contraction on the conformational preferences of a-substituted proline analogs

     Revilla Lopez, Guillermo; Warren, Javier G.; Torras Costa, Juan; Jiménez, Ana I.; Cativiela, Carlos; Aleman Llanso, Carlos Enrique
    Biopolymers
    Date of publication: 2012-03-01
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    The structural consequences derived from the incorporation of either a methyl or a phenyl group at the a carbon of proline were recently investigated by quantum mechanical calculations (J Org Chem 2008, 73, 3418). In this work, the effect produced by contraction of the pyrrolidine ring on such a-substituted proline analogs has been explored using the same computational methods. Specifically, the intrinsic conformational preferences of the N-acetyl-N 0 -methylamide derivatives of the lower proline homolog L-azetidine-2-carboxylic acid (Aze), characterized by a four- instead of a fivemembered ring, and its a-methyl (aMeAze) and aphenyl (aPhAze) derivatives have been determined using quantum mechanical calculations and compared to those observed before for the proline counterparts. Replacement of the pyrrolidine ring by an azetidine cycle leads to a reduction of the conformational flexibility, especially for the Aze and aMeAze derivatives, which should be attributed to the quasi-planar geometry of the fourmembered ring. Furthermore, the azetidine nitrogen shows pyramidalization, which depending on the peptide backbone conformation favors the formation of an attractive N–H N interaction or alleviates a severe steric hindrance. Calculations on different environments predict that the tendency of aMeAze to adopt g-turns is higher than that of unsubstituted Aze and amethylproline, this feature being in full agreement with the experimental observations available

  • Thermodynamic and stereochemical aspects of the polymerizability of glycolide and lactide

     Aleman Llanso, Carlos Enrique; Bertran Cànovas, Oscar; Houk, K.N.; Padias, Anne Buyle; Hall, H.K.
    Theoretical chemistry accounts
    Date of publication: 2012-03-01
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    The ring-opening polymerizations of the dilactones glycolide and the S,S- and S,R-stereoisomers of lactide were studied using quantum mechanical methods. The ring strain and the conformational distribution of these cyclic monomers and of the polymers were calculated, and the effect of the medium on the polymerization was predicted, for both bulk and solution. The polymerizability of the three monomers in the gas phase, that is, nonpolar medium, is much greater than that of d-valerolactone or 1,4-dioxan-2-one. This difference vanishes in the polar medium chloroform, which is attributed to the fact that, while all of these monomers possess polar cis-lactone bonds, the three dilactones possess small dipole moments. The data are combined to give polymerization enthalpy and free energy values. The four stereoregular lactide polymers did not differ significantly in energy. Accordingly, the ability to synthesize any one of these rests on catalyst specificity (‘‘polymer chain-end control’’). Although introduction of sterically demanding methyl groups into glycolide is expected to favor coiled conformations and decrease polymerizability, this was not found to be the case. Good agreement of calculated values with experimental data from the literature was achieved.