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Electrochemical Polymerization (electrochemical + polymerization)
Selected AbstractsElectrochemical Preparation of Poly(acriflavine) Film-Modified Electrode and Its Electrolcatalytic Properties Towards NADH, Nitrite and Sulfur OxoanionsELECTROANALYSIS, Issue 9 2007Shen-Ming Chen Abstract Electrochemical polymerization of acriflavine (AF) was carried out onto glassy carbon electrodes (GCE) from the aqueous buffer solution containing 1.5×10,3,M AF monomer (pH,3.5) which produced a thin electrochemically active film. This is noted as poly(AF) film modified electrodes (PAF/GCE). This modified electrode was shown a stable reversible redox couple centered at +0.22,V in pH,3.5 buffer solutions. PAF/GCE was found to be more stable in acidic solutions and its formal potential was found to be pH dependent with a slope close to ,60,mV/pH. The electrochemical deposition kinetics of poly(AF) onto gold coated quartz crystal was studied by using electrochemical quartz crystal microbalance (EQCM) combined with cyclic voltammetry (CV). PAF/GCE was found be good mediator for electrochemical oxidation of reduced nicotinamide adenine dinucleotide (NADH) in pH,5 buffer solutions. The electrocatalytic oxidation of SO and electrocatalytic reduction of NO, SO and S2O were carried out at PAF/GCE electrode in acidic aqueous solutions. The electrocatalytic oxidation of NADH was also investigated by using amperometric method. [source] Electrochemical polymerization of pyrrole in cholesteric liquid crystals: Morphology and optical propertiesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 8 2007Hiromasa Goto Abstract Electrochemical polymerization in a cholesteric liquid-crystal electrolyte was carried out. Polypyrrole thus synthesized in a cholesteric liquid-crystal electrolyte could be clearly seen to form a specific morphology. The polypyrrole films exhibited chiroptical properties and formed various surface structures such as Schlieren, Nazca-line, sea-anemone, and wire-loop structures. These structures that developed during polymerization were preserved even after washing. Moreover, no chiral molecule reacted chemically with the monomer during polymerization, and the electrolyte functioned only as a matrix chiral continuum. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1377,1387, 2007. [source] Electrochemical polymerization and characterization of polyether-substituted aniline derivativesPOLYMER INTERNATIONAL, Issue 8 2007Seha Tirke Abstract New compounds consisting of aniline units linked by polyether bridges have been synthesized and their electrochemical polymerization was performed via constant potential electrolysis and cyclic voltammetry in an aqueous solution containing 3.0 mol L,1 H2SO4. Chemical polymerization was carried out using (NH4)2S2O8 as oxidizing agent. It was found that both methods gave the same polymer product without any cleavage of the polyether bridge between aniline rings. The polymers were characterized using the Fourier transform infrared spectroscopic technique and the thermal behavior of electrochemically prepared polymers was investigated using thermogravimetric analysis. Spectroelectrochemical properties of the films were investigated using the in situ UV-visible spectroscopic technique. Copyright © 2007 Society of Chemical Industry [source] Chemical and electrochemical synthesis of conducting graft copolymer of acrylonitrile with anilinePOLYMER INTERNATIONAL, Issue 9 2006S Hossein Hosseini Abstract A new conducting copolymer, polyacrylonitrile- graft -polyaniline (PAN- g -PANi), has been prepared by chemical and electrochemical methods from a precursor polymer. Poly[acrylonitrile- co -(acrylimine phenylenediamine)] (PAN- co -PAIPD) was synthesized chemically by reacting PAN with sodium 1,4-phenylenediamine salt. PAN- g -PANi was synthesized chemically using ammonium peroxydisulfate as the oxidant and p -toluenesulfonic acid in dimethylsulfoxide solution and adding aniline to oxidized PAN- co -PAIPD. Electrochemical polymerization was carried out by spin coating PAN- co -PAIPD on the surface of a Pt electrode, then the growth of the graft copolymer (PAN- g -PANi) in the presence of fresh aniline and acidic solution. The structures of the graft copolymer and PAN- co -PAIPD were characterized using UV-visible, Fourier transform infrared, and 1H and 13C NMR spectroscopies. The thermal properties of PAN- g -PANi were studied using thermogravimetric analysis and differential scanning calorimetry. Scanning electron microscopy (SEM) images showed that the morphology of PAN- g -PANi copolymer films was homogeneous. Electrical conductivity of the copolymer was studied using the four-probe method, which gave a conductivity of 4.5 × 10,3 S cm,1 with 51.4% PANi. SEM and electrical conductivity measurements supported the formation of the graft copolymer. Copyright © 2006 Society of Chemical Industry [source] Electrochemical polymerization of chiral pyrrole derivatives in electrolytes containing chiral camphor sulfonic acidPOLYMER INTERNATIONAL, Issue 10 2004GY Han Abstract N -Substituted pyrrole derivatives with chiral side groups have been synthesized and electrochemically polymerized in acetonitrile containing tetrabutylammonium perchlorate (TBAClO4) and (S)-(+)-camphor-10-sulfonic acid ((S)-(+)-CSA) or (R)-(,)-camphor-10-sulfonic acid ((R)-(,)-CSA). The resulting N -substituted polypyrrole films were characterized by cyclic voltammetry, infrared, Raman and X-ray photoelectron (XPS) spectroscopies. XPS results demonstrated that the as-grown polymer films are preferably doped by CSA anions when the monomer and the CSA anion have the same optical rotation dispersion (ORD). Furthermore, the conductivities of the polymers synthesized in the media containing CSA with the same ORD of the corresponding monomers were measured to be about 2,10 times higher than those of polymers obtained from electrolytes without CSA. Copyright © 2004 Society of Chemical Industry [source] Affinity Biosensors Based on Electropolymerized FilmsELECTROANALYSIS, Issue 19 2005Serge Cosnier Abstract This review gives an overview on different types of affinity biosensors based on electropolymerized polymer films that are becoming an important class of analytical tools. These affinity biosensors may be classified according to the strategy used for their fabrication, namely entrapment within polymers during their electrochemical growth, simple adsorption onto electropolymerized films, chemical coupling or affinity interactions between bioreceptors and electropolymerized films or direct electrochemical polymerization of the bioreceptor itself. Recently opened perspectives and potential research directions are also discussed. [source] An Optically Active Polythiophene Exhibiting Electrochemically Driven Light-Interference ModulationADVANCED FUNCTIONAL MATERIALS, Issue 9 2009Hiromasa Goto Abstract Optically active polythiophene (PT*) is successfully prepared by electrochemical polymerization using a cholesteric liquid crystal (CLC) electrolyte solution. Polarizing optical microscopy observations of the polymer reveal a well-resolved fingerprint texture similar to the optical texture of the CLC. Circular dichroism measurements indicate a Cotton effect. The PT* film produced by the asymmetric polymerization in CLC exhibits a variable diffraction function, electrochemically driven refractive index modulation, and electrochromism originating from the periodic dielectric structure, representing a form of structural electrochromism. [source] Multifunctional Nanobiomaterials for Neural InterfacesADVANCED FUNCTIONAL MATERIALS, Issue 4 2009Mohammad Reza Abidian Abstract Neural electrodes are designed to interface with the nervous system and provide control signals for neural prostheses. However, robust and reliable chronic recording and stimulation remains a challenge for neural electrodes. Here, a novel method for the fabrication of soft, low impedance, high charge density, and controlled releasing nanobiomaterials that can be used for the surface modification of neural microelectrodes to stabilize the electrode/tissue interface is reported. The fabrication process includes electrospinning of anti-inflammatory drug-incorporated biodegradable nanofibers, encapsulation of these nanofibers by an alginate hydrogel layer, followed by electrochemical polymerization of conducting polymers around the electrospun drug-loaded nanofibers to form nanotubes and within the alginate hydrogel scaffold to form cloud-like nanostructures. The three-dimensional conducting polymer nanostructures significantly decrease the electrode impedance and increase the charge capacity density. Dexamethasone release profiles show that the alginate hydrogel coating slows down the release of the drug, significantly reducing the burst effect. These multifunctional materials are expected to be of interest for a variety of electrode/tissue interfaces in biomedical devices. [source] Vertically aligned polypyrrole drawing a fingerprint array prepared by electrochemical polymerization in chiral nematic electrolyteJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 2 2006Hiromasa Goto A new electrochemical polymerization method for preparing vertically aligned polypyrrole drawing a fingerprint array was developed. Polymerization of Py in the chiral nematic liquid crystal (N*-LC) produces vertical alignment of the fibril structure. Here, the N*-LC plays a role of a molecular vessel. The fibril can grow with forming vertically aligned fibril structure along the fingerprint texture of N*-LC by electrochemical polymerization process. [source] Ionic liquids in the synthesis and modification of polymersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 20 2005Przemys, aw Kubisa Abstract Ionic liquids are organic salts that are liquid at ambient temperatures, preferably at room temperature. They are nonvolatile, thermally and chemically stable, highly polar liquids that dissolve many organic, inorganic, and metallo-organic compounds. Many combinations of organic cations with different counterions are already known, and the properties of ionic liquids may be adjusted by the proper selection of the cation and counterion. In the last decade, there has been increasing interest in using ionic liquids as solvents for chemical reactions. The interest is stimulated not only by their nonvolatility (green solvents) but also by their special properties, which often affect the course of a reaction. In recent years, ionic liquids have also attracted the attention of polymer chemists. Although the research on using ionic liquids in polymer systems is still in its infancy, several interesting possibilities have already emerged. Ionic liquids are used as solvents for polymerization processes, and in several systems they indeed show some advantages. In radical polymerization, the kp/kt ratio (where kp is the rate constant of propagation and kt is the rate constant of termination) is higher than in organic media, and thus better control of the process can be achieved. Ionic liquids, as electrolytes, have also attracted the attention of researchers in the fields of electrochemical polymerization and the synthesis of conducting polymers. Finally, the blending of ionic liquids with polymers may lead to the development of new materials (ionic liquids may act as plasticizers, electrolytes dispersed in polymer matrices, or even porogens). In this article, the new developments in these fields are briefly discussed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4675,4683, 2005 [source] Helical opposition in poly(2-methoxyaniline) by tuning the concentration of salts in reaction solutionPOLYMER INTERNATIONAL, Issue 9 2010Guo-Li Yuan Abstract The synthesis and application of helical polyaniline derivatives (PANIs) have attracted much interest. However, most of these syntheses have been carried out in organic solutions. In our previous reports, helical PANIs were successfully realized in aqueous solution. Because helical architecture in the backbones of PANIs is an induced rather than the natural arrangement, it is significant to study the change in helicity in aqueous solution, especially opposition or reversion. One excess-handed helicity was induced in poly(2-methoxyaniline) (PMOA) by electrochemical polymerization of 2-methoxyaniline at pH = 2.5 in the presence of protonated ,-cyclodextrin sulfate (CDS, H+). When 0.04 mol L,1 NaCl was added to the reaction solution, the PMOA backbone took on an opposite excess of one-handed helicity, which was confirmed by induced circular dichroism. Such a result originates from the dynamic switch between electrostatic and hydrogen-bonding interactions. The helix-inducing process in PMOA depends on the interaction between PMOA and chiral CDS. Due to the competition of Na+ Cl, with PMOA+ CDS,, the electrostatic interaction between PMOA and CDS is limited or weakened. Thus, the slightly preferred interaction between them switches from electrostatic to hydrogen bonding. Simultaneously, the interaction positions and distance are changed. The changed steric hindrance induces PMOA into adopting an opposite excess-handed helicity. Copyright © 2010 Society of Chemical Industry [source] Electrochemical polymerization and characterization of polyether-substituted aniline derivativesPOLYMER INTERNATIONAL, Issue 8 2007Seha Tirke Abstract New compounds consisting of aniline units linked by polyether bridges have been synthesized and their electrochemical polymerization was performed via constant potential electrolysis and cyclic voltammetry in an aqueous solution containing 3.0 mol L,1 H2SO4. Chemical polymerization was carried out using (NH4)2S2O8 as oxidizing agent. It was found that both methods gave the same polymer product without any cleavage of the polyether bridge between aniline rings. The polymers were characterized using the Fourier transform infrared spectroscopic technique and the thermal behavior of electrochemically prepared polymers was investigated using thermogravimetric analysis. Spectroelectrochemical properties of the films were investigated using the in situ UV-visible spectroscopic technique. Copyright © 2007 Society of Chemical Industry [source] Electrochemical behaviour and electrochemical polymerization of fluoro-substituted anilinesPOLYMER INTERNATIONAL, Issue 8 2002Atilla Cihaner Abstract The electrochemical behaviour of three fluoro-substituted aniline monomers, 2-fluoroaniline (2FAN), 3-fluoroaniline (3FAN) and 4-fluoroaniline (4FAN), was investigated in aqueous acidic and organic media by means of cyclic voltammetry (CV) studies. Constant potential electrolysis (CPE) of the monomers in acetonitrile,water mixture (1:1 by volume) using NaClO4 as supporting electrolyte yielded soluble polymers. The mechanism of electrochemical polymerization was investigated using in situ electron spin resonance (ESR) and in situ UV,VIS spectroscopic techniques for one of the monomers (4FAN). Both CV and in situ UV,VIS measurements indicated that the polymers obtained are in the emeraldine base form. In situ ESR studies indicated that electrochemical polymerization involves a radical-cation as an intermediate. Characterization of polymer products have been carried out using FTIR and NMR spectroscopic techniques, and thermal behaviour was studied using differential scanning calorimetry (DSC). It was found that conductivity can be imparted to as-synthesized polyfluoroanilines via iodine doping. © 2002 Society of Chemical Industry [source] Electroinduced oxidative copolymerization of N -vinyl carbazole with methyl ethyl ketone formaldehyde resinPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 7 2004s Ustamehmeto Abstract In this study, a novel procedure to obtain the non-crosslinked, photoconductive, white form of the linear copolymer of N -vinyl carbazole (NVCz) and methyl ethyl ketone formaldehyde resin (MEKF-R) is reported. A possible mechanism of copolymerization is suggested. The yield of the copolymer is increased almost 10 times by the addition of catalytic amounts of ceric ammonium nitrate as an oxidant during the electrochemical polymerization of NVCz in the presence of MEKF-R in a divided electrochemical cell. Since cerium(III) is readily oxidized to cerium(IV) at the anode, the concentration of cerium(IV) remained constant and the deposition of green poly(NVCz) can be prevented. Copyright © 2004 John Wiley & Sons, Ltd. [source] ,-Substituted Terthiophene [2]RotaxanesCHEMISTRY - A EUROPEAN JOURNAL, Issue 19 2009Taichi Ikeda Dr. Abstract Towards polythiophene polyrotaxanes: The ,-substituted terthiophene [2]rotaxanes have been synthesized (see figure). Basic optical and electrochemical properties of the synthesized [2]rotaxanes are also reported. Two kinds of ,-substituted terthiophene [2]rotaxanes were synthesized using the host-guest pairs of the electron-deficient cyclophane cyclobis(paraquat- p -phenylene) (CBPQT4+) and the electron-rich terthiophenes with diethyleneglycol chains at the ,-position. One is made from the ,-position non-substituted terthiophene (3,T-,-Rx) and the other is made from the ,-dibromo-substituted terthiophene (3,TBr-,-Rx). The binding constants of the ,-substituted terthiophene threads were confirmed to be smaller than that of the ,-substituted terthiophene analogue. By UV/Vis absorption measurements, we confirmed the charge-transfer (CT) band in the visible region with an extinction coefficient of ,102 (M,1,cm,1). Strong, but not quantitative, quenching of the terthiophene fluorescence was confirmed for the [2]rotaxanes. Although the ,-substituted terthiophene thread was electrochemically polymerizable, the [2]rotaxane 3,T-,-Rx was not polymerizable. This result indicates that the interlocked CBPQT4+ macrocycle effectively suppresses the electrochemical polymerization of the terthiophene unit because electrostatic repulsive and steric effects of CBPQT4+ hinder the dimerization of the terthiophene radical cations. In the electrochemical measurement, we confirmed the shift of the first reduction peak towards less negative potential compared to free CBPQT4+ and the splitting of the second reduction peak. These electrochemical behaviors are similar to those observed for the highly-constrained [2]rotaxanes. The ,-substituted terthiophene [2]rotaxanes reported herein are important key compounds to prepare polythiophene polyrotaxanes. [source] Electrosynthesis of Poly(para)phenylene in an Ionic Liquid: Cyclic Voltammetry and in Situ STM/Tunnelling Spectroscopy StudiesCHEMPHYSCHEM, Issue 3 2008T. Carstens Abstract The electropolymerization of benzene in the air and water-stable ionic liquid 1-hexyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate (HMIm)FAP is investigated. The study comprises cyclic voltammetry, IR and in situ STM/tunnelling spectroscopy measurements. The IR results indicate that poly(para)phenylene is the end product of the electropolymerization of benzene in the employed ionic liquid. The resulting conjugation lengths of the product fall between 19 and 21. A polymer reference electrode is used successfully for the electrochemical polymerization of benzene. The first in situ STM results show that the electropolymerization of benzene in the ionic liquid can be probed on the nanoscale and the band gap of the prepared polymer can be determined. The electrodeposited polymer film obtained at a constant potential of 1.0 V vs PPP (polyparaphenylene) exhibits a band gap of 2.9±0.2 eV. [source] Electrochemical synthesis of PEDOT derivatives bearing imidazolium-ionic liquid moietiesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 12 2009Markus Döbbelin Abstract Novel poly(3,4-ethylenedioxythiophene) (PEDOT) polymers bearing imidazolium-ionic liquid moieties were synthesized by electrochemical polymerizations. For this purpose, new functional monomers were synthesized having an 3,4-ethylenedioxythiophene (EDOT) unit and an imidazolium-ionic liquid with different anions such as tetrafluoroborate (BF), bis(trifluoromethane)sulfonimide ((CF3SO2)2N,), and hexafluorophosphate (PF). Next, polymer films were obtained by electrochemical synthesis in dicholoromethane solutions. Obtained polymers were characterized, revealing the characteristics of PEDOT in terms of electrochemical and spectroelectrochemical properties, FTIR, 1H NMR, and AFM microscopy. Interestingly, the hydrophobic character of electropolymerized films could be modified depending on the anion type. The hydrophobicity followed the trend PF > (CF3SO2)2N, > BF > pure PEDOT as determined by water contact angle measurements. Furthermore, the polymers could be dissolved in a range of polar organic solvents such as dimethylformamide, propylene carbonate, and dimethyl sulfoxide making these polymers interesting candidates for wet processing methods. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3010,3021, 2009 [source] | |||||||||||||