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The electrochemical polymerization of polypyrrole nanowires is carried out using potentiodynamic and galvanostatic methods in order to enhance the performance of the modified electrodes as capacitor devices. The electrochemical, spectroscopic, and morphological properties are determined through cyclic voltammetry, Raman spectroscopy and scanning el...
In this work, platinum electrodes are modified with poly[4-(3-hexyl-2-thiophene)-aniline], PTANIr2, and characterized by cyclic voltammetry. In the presence of nitrate in the electrolytic medium, an oxidation signal at 0.6 V vs . SCE is recorded, so the response of this modified electrode, Pt|PTANIr2, is evaluated to determine its relationship with...
Modification with polypyrrole nanowires, PPy-nw, is accomplished directly upon the working electrode by electrochemical polymerization methods using mesoporous silica as a template. The silica template is prepared by a potentiostatic method, generating a homogeneous film over a previously deposited thin layer of PPy, so that PPy-nw grows within the...
Studying the electrochemical characteristics is an important step for determining interactions between molecules and the chemical environment. Moreover, the electrochemical evaluation of dyes is highly needed to establish the behavior of electro-active chemical species inside dye-sensitized solar cells (DSSCs). Four compounds, M8-1, M8-2, M8-O1, an...
The relationship between the p-doping/undoping process (charge, stability and reversibility) and the nucleation and growth mechanisms concerning the influence of the type of electrochemical perturbation of the system during the electropolymerization of pyrrole (PPy) by oxidation of the monomer, is reported in the presence of different salts (LiClO4...
In the continuous search for new compounds for solar devices, the family of dipolar D-π-A molecules, which have a donor (D) and an acceptor (A) charge joined by a conjugate bridge, have been the focus of attention in the recent years due their different properties. As we have shown before, there is a connection between the geometry of molecules bas...
A systematic steel and platinum electrodes were modified via drop-coating with polymers based on aniline and thiophene or aniline and 3-alkylthiophene previously synthesized and reported by us. Having in mind the possible applications of these materials, electrochemical (cyclic voltammetry, CV, in different electrolytic solutions), morphological an...
The study of new dipolar A-π-D molecules, which have an acceptor (A) and donor (D) charge joined by a conjugate bridge, have been an attention focus in the recent years due their different properties. In the current work, a molecular system has been modified in order to compare the effect on properties, such as quantum yield. Thus, two series were...
Conducting polymer nanostructuring enables a substantial improvement of many electro-catalytic processes, e.g., formic acid (HCOOH, FA) electro-oxidation. In this case, a stainless steel (SS) electrode is first modified with poly(1-amino-9,10-anthraquinone-co-o-phenylenediamine) (COP) and then, by means of a template that can be chemically removed,...
A systematic study of the influence of the type of electrochemical perturbation, in the presence of various salts, namely LiClO4, TBAClO4, TBAPF6, TEAPF6, LITFMS or TBATFMS in acetonitrile, on the electropolymerization of 3,4-ethylenedioxythiophene on platinum was accomplished. Poly(3,4-ethylenedioxythiophene) (PEDOT) electrodeposits were electroch...
Poly(1-amino-9,10-anthraquinone) (P1AAQ) nanowires have been directly electro-synthesized on a steel electrode, previously modified with a thin film of poly(P1AAQ-co-o-phenylenediamine), via a SiO2 mesoporous template. Nanostructures obtainment was verified by electrochemical techniques and TEM. After template removal, it was corroborated that the...
Using the methodology previously reported for the obtaining of polythiophene by electrochemical methods, on a silica template modified Pt electrode, that tunes the growth into its pores confined space, in the current paper poly(3,4-ethylenedioxythiophene) (PEDOT) nanowires, also obtained directly on the electrode surface, were prepared. The Pt elec...
One of the new uses for polyanilines (PANIs) is as sensors, being able to measure the concentration of different types of compounds. As a positive charge exists on PANI's nitrogen, nucleophilic compounds can interact with the polymer leading to an observable and measurable change. In this case, modification of Pt electrodes with polymers derived fr...
The electro-synthesis of poly(3,4-ethylenedioxythiophene), PEDOT, has been widely studied due to its different and important applications. Considering that one of the most important electrochemical characteristics of this polymer is its ability to undergo p- and n-doping/undoping, our research group has tested its potential usefulness for cations e...
Two new conjugated polymers, poly(2,3-di(thiophen-2-yl)pyrido[2,3-b]pyrazine) and poly(2,3-di(thiophen-2-yl)pyrido[3,4-b]pyrazine), based on thiophene and pyridine rings were chemically and electrochemically synthesized and characterized by IR, UV-Vis and elemental analysis. Monomers were chemically synthesized at high yield percentages and charact...
The present work deals with copolymers synthesized by reacting aniline units or blocks with 2,6-di(thiophen-2-yl)aniline and 2,2'-(thiophen-2,5-diyl)dianiline monomers. Characterization by spectroscopic techniques such as FT-IR, UV-vis, 1H-NMR corroborated the formation of true copolymers. Synthesized products showed improved solubility and better...
Nanostructures of poly(2,2':5',2″-terthiophene) have been synthesized using only electrochemical techniques. To this end, a porous silica film modified platinum disc was used as working electrode (Pt|(SiO2) n). The silica coating acts as a template so that the subsequent electro-polymerization occurs in their confined space pores, perpendicular to...
Polyanilines have different macroscopic properties according to the substituent incorporated into their monomers. Being conducting polymers, one of these properties is conductivity, which may increase or decrease depending on the substituent and its position in the chain. This work is focused on the modification of aniline monomers, which character...
Poly(1-amino-9,10-anthraquinone-co-o-phenylenediamine) (P1AAQ-co-POPD) was synthesized by electrochemical methods on stainless steel electrodes (SS) using equal monomer concentration in acetonitrile/acidified water mixture as solvent. Electrochemical characterization allows, among others, determining the characteristic redox couple potential of the...
The current work studies the effect of ultrasound on nucleation and growth mechanisms (NGM) from the respective i-t transients obtained during the electro-polymerization of ortho-anisidine (OAN) and aniline (ANI), using a potentiostatic (potential step) approach. To this end, optimum electro-synthesis working conditions were searched for using cycl...
In this work temperature effect on poly(ortho-anisidine), POAN, and polyaniline, PANT, nucleation and growth (NGM) mechanism was studied. Synthesis conditions using potentiodynamic method (cyclic voltammetry) at all operating temperatures were first optimized; it was found that as the system cools, the monomer oxidation potential increases. The i-t...
We investigated the effect of a CuI anode buffer layer (ABL) on the molecular orientation of the copper phthalocyanine (CuPc) in organic photovoltaic cells (OPV cells), and we compare it to the effect of MoO3 buffer layer. While, in the presence of CuI, the CuPc molecules lie down parallel to the substrate, they stand up perpendicular in the case o...
3,4-ethylenedioxythiophene (EDOT) was electro-polymerized by potentiodynamic (scan potential range between -1.0 and 1.5 V vs SCE) and potentiostatic method (potential step of 1.4 V during 5 min) on stainless steel AISI 316 (SS) electrodes, using lithium perchlorate as support electrolyte in acetonitrile, to obtain the modified electrode SS|PEDOT, t...
Polyaniline derivatives were synthesized using chemical methods by varying the oxidant concentration to favor the quinoid units formation. FT-IR, UV-vis and cyclic voltammetry characterization cnclusively demostrated that polymer oxidation becomes more difficult as the size of the substituent increases. At the same time, lager substituent size tend...
Organic photovoltaic cells using polymer belonging to the aniline-heteroaryl family as electron donor have been achieved by thermal evaporation. We show that the properties of the polymer film, morphology, molecule order and conductivity depend strongly on the bottom anode buffer layer. While cells without anode buffer layer or with MoO3 or CuI ano...
In this research, poly(α-tetrathiophene), poly(α-TTP), was potentiostatic and potentiodynamically electrosynthesized on Pt and F-doped SnO2 electrodes. The solvent effect (CH2Cl2 and CH3CN) on the nucleation and growth mechanism, NGM, and morphology of the respective deposit was established by potentiostatic method and scanning electron microscopy...
A new series of polymers, chemically and electrochemically obtained from monomers containing aniline and thiophene moieties, has been prepared. The purpose is to use them as electron donor layers in the fabrication of dual-layer organic solar cells. Both the monomers and the polymers were characterized using techniques such as NMR, FT-IR, cyclic vo...
Temperature and ultrasound effect on the nucleation and growth mechanisms (NGM) of poly(ortho-toluidine) (POT) was investigated. Synthesis conditions at temperatures between 263 and 303 K were optimized with and without ultrasonic irradiation. The obtained i-t transient is complex and its deconvolution showed to be made up of three contributions th...
Monomers composed of thiophene and aniline rings, 4-(2-thiophen)aniline and 4-(3-thiophen)aniline, were successfully synthetized through the Suzuki-Miyaura cross coupling reaction and then polymerized. The polymers poly 4-(2-tiophen)aniline and poly 4-(3-tiophen)aniline (P4,2TA and P4,3TA) were characterized via spectroscopycal NMR, optical and ele...
3,4-ethylenedioxythiophene (EDOT), 3,4-propylenedioxythiophene (PRODOT), 3,4-ethylenedioxypyrrole (PEDOP) and 3,4 propylenedioxypyrrole (PRODOP), thiophene and pyrrole derivatives, were electro-polymerized by potentiodynamic and potentiostatic methods on stainless steel AISI 316 electrodes, using lithium perchlorate as support electrolyte in aceton...
Intrinsic properties of conducting polymers, such as oxidation potential and band gap, are very important for designing new materials with improved properties. Computa-tional chemistry offers suitable tools capable of predicting these quantities. This work presents electrochemical informa-tion about accurate oxidation potentials of oligothiophenes...
In this paper electrode miniaturization with prospective use in electro-catalysis or as sensors is proposed. To this purpose it was postulated that dispersion of metal particles in a polymer matrix increases the effective area, on the same geometric area. In addition, the catalytic effect would significantly improve the sensitivity and detection li...
To improve the performances of organic solar cells, many efforts have been devoted to the synthesis of new compounds whose absorption spectra allow a better matching with that of the solar spectrum. To that respect, a new poly(isothianaphthene) derivative, with a low band gap, called, poly(benzo[c]thiophene-2-oxide), was synthesized and characteriz...
Multi-heterojunction Organic solar cells based on small molecule have been deposited in vacuum by sublimation. The heart of the cell consists in a three superposed multilayers structure. A blend Cu-phthalocyanine:fullerene (Cu-Pc:C60) or CuPc:perylene derivative (CuPc:PTCBI) deposited by co-evaporation is sandwiched between a CuPc and a C60 (or PTC...
In optoelectronic devices, the work function of the transparent conductive oxide, which is used as anode, does not match well the highest occupied molecular orbital of the organic material, which induces the formation of a barrier opposed to hole exchange at this interface. Therefore a thin buffer layer is often used to achieve good matching of the...
The nucleation and growth mechanism of some homopolymers of aniline (six monomers were studied: 3,5-dichloroaniline, 2,5-dichloroaniline, 2,6-dichloroaniline, 2,3-dichloroaniline, 2,5-dibromoaniline, and 2,6-dibromoaniline), synthesized by potentiostatic methods, was determined with a mathematical model that considers different contributions from c...
In a previous work 3′,4′-dibromo substituted polythiophene film was used to produce an electronic device with photovoltaic characteristic but only 0.006% yield was achieved. In an effort to understand the reason of this low-yield, we intend to elucidate the effect of substituents of terthiophene compounds on the morphological characteristics and co...
The variation of the open circuit voltage of organic photovoltaic cells based on a donor/acceptor heterojunction was studied as a function of the couple donor/acceptor and of the encapsulation process used for the cells. The donors used were zinc and copper phthalocyanine and the acceptors were fullerene, perylene-3,4,9,10-tetracarboxylic dianhydri...
Polyterthiophene (PTT) thin films have been electrosynthesized using potentiodynamic and potentiostatic methods. The optimal experimental conditions to prepare organic solar cells were determined by deposition of films on platinum and then the process was adapted to an indium tin oxide substrate. Surface morphology of films deposited by potentiosta...
In the present work the electrochemical study of compounds based on 3-((ω-bromoalkyloxy) methyl) thiophene, varying the length of the alkyl chain between 6 and 12 carbon atoms, is reported. Electropolymerization of the monomers was achieved by potentiodynamic (cyclic voltammetry, CV) and potentiostatic (constant potential) techniques. Voltammograms...
Al or Sn doped ZnO films were deposited by spray pyrolysis using aqueous solutions. The films were deposited on either indium tin oxide coated or bare glass substrates. ZnCl2, AlCl3 and SnCl2 were used as precursors. The effect of ZnCl2 molar concentration (0.1–0.3M) and doping percentage (2–4% AlCl3 or SnCl2) have been investigated. The main goal...
Poly(pyridylureas) and poly(pyridylthioureas) were synthesized by reacting 2,6-diaminopyridine with phosgene and thiophosgene, respectively, using THF and pyridine as solvent. The synthesized polymers were characterized by IR-spectroscopy, elemental analysis, and X-ray photoelectron spectroscopy. Thermal stability of the polymers was determined by...
Thiophene structures anchored in position 3 of the ring were synthesized using spacers of different lengths (6,8,10, and 12
carbon atoms linked to a 2-((4-octylphenylimino)methyl)phenol) group. The thermal studies of the units demonstrated that they
possess liquid-crystal properties and their optical study indicated that all the compounds present a...
Polycarbonates and polythiocarbonates derived from diphenols containing Si or Ge, bis(4-hydroxyphenyl)-dimethyl-germane (I), bis(4-hydroxyphenyl)-diphenyl-germane (II), bis(4-hydroxy-phenyl)-dimethyl-silane (III), and bis(4-hydroxyphenyl)-diphenyl-silane (IV), and phosgene (a) or thiophosgene (b), respectively, were synthesized under phase transfer...
Organic microelectronic devices performances are strongly dependant on the energy level alignment of their different constituents
(electrode/organic, organic/organic). The cyclic voltammograms (CV) of 1.4-diaminoanthraquinone (1,4-DAAQ) have been measured.
The CV curves of 1,4-DAAQ show a one electron reversible reduction and oxidation wave. The en...
Recent studies on conducting polymers have demonstrated that polymers of 3-substituted thiophene produce very stable compounds. Although this kind of substitution improves the regularity, structural defects still exist. To overcome this drawback, the polymerization of 3,4-disubstituted thiophene is proposed as a convenient way of synthesizing regul...
The electropolymerization process of N-vinylcarbazole in anhydrous medium in the presence of 2,6-tert-butyl-a-(3,5-di-terbutyl-4-oxo-cyclohexadien-1-ylidene)-p-tolyloxy
(Galvinoxyl), stable nitroxide radical, was studied. Electrolysis of the monomer at constant potential in the presence of
Galvinoxyl, generated an adduct between both species. In or...
A new family of conjugated polymers formed by 3-alkyloximethylthiophenes substituted with a biphenyl group was synthesised by a route involving first the coupling of a functionalised alkyl chain, from 8 to 12 carbon atoms, to 3-methanolthiophene, and then the attachment of the mesogen group. The monomer was characterised by conventional techniques,...
A new conjugated polymer combining in its structure thiophene rings and nitrogen containing heterocycles, poly[2,3-di(2-thienyl)quinoxaline],
was synthesized by electrochemical methods using different experimental conditions. The monomer was electrochemically characterized.
The morphology of the respective polymer was studied by SEM. The polymer sh...
Summary A new family of conjugated polymers formed by 3-alkyloximethylthiophenes substituted with a biphenylcarbonitryl group was synthesized by a route involving first the coupling of a functionalized alkyl chain, from 6 to 12 carbon atoms, to 3-methanolthiophene, and then the attachment of the mesogenic group. The monomeric units were characteriz...
The influence of electrolyte and deposition potential on polyfurane doped/undoped electrogenerated films was analyzed by potentiodynamic profiles and current–time transients. The films were formed on platinum electrodes from the monomer and tetrabutylammonium hexafluorophosphate, tetrabutylammonium tetrafluoroborate, or tetraethylammonium perchlora...
Summary Bis(m-aminophenyl)diselenide was synthesized by diazotation of m-nitroaniline followed by incorporation of potassium selenium cyanate, and the reduction of the nitro groups by addition of tin and concentrated HCl. This dihydrochloride monomer was polymerised using ammonium persulphate in 0.25 M HCl as oxidizing agent. Copolymers of aniline...
The influence of electrolyte and monomer concentration on
properties and morphology of electrochemically obtained
polyselenophene films doped and undoped with hexafluorophosphate
and tetrafluoroborate anions was analyzed. The films were
deposited on SnO2-coated glass in a
classical three-electrode cell from the monomer and the
electrolyte in anhydr...
The chemical copolymerization of aniline and 2,5-dibromoaniline or 2,6-dibromoaniline by oxidation with K2Cr2O7 in H2SO4/acetonitrile media has been carried out. Copolymer composition can be effectively controlled varying the monomer feed ratio. When substituted aniline fraction is increased in the copolymer, the electrical conductivity (s) decreas...
The anodic electropolymerization process of 2,2' dithienyl ketone in acetonitrile or dichloromethane electrolytic solutions on Pt, Au or SnO2 electrodes, has been studied by means of cyclic voltammetry and potential step methods. The electrochemical response indicates that the electro-oxidation process is slightly solvent dependant, but the electro...
The anodic electropolymerization process of 2,2' dithienyl ketone in acetonitrile or dichloromethane electrolytic solutions on Pt, Au or SnO2 electrodes, has been studied by means of cyclic voltammetry and potential step methods. The electrochemical response indicates that the electro-oxidation process is slightly solvent dependant, but the electro...
The thermal properties of poly(carbonates) and poly(thiocarbonates) containing silicon or germanium in the main chan, derived from thediphenolsbis(4-hydroxy-phenyl)-dimethylsilane, bis(4-hydroxyphenyl)-dimethylgermane, bis(4-hydroxy-phenyl)-diphenylsilane and bis(4-hydroxyphenyl)-diphenylgermane, and phosgene or thiophosgene, were studied by differ...
Poly(ether-ester)s from (2,2-bis(1,4-phenyleneoxy)-propylidene)-diacetic acid and related diacids with diphenols were synthesized using several ammonium and phosphonium salts as phase transfer catalysts. The best results were obtained with benzyltriethylammonium chloride, which is a hydrophilie catalyst that not promotes hydrolysis of the polymeric...
Polyesters derived from diphenols containing Si or Ge and isophthalic and terephthalic acids dichlorides have been synthesized using phase transfer conditions, and characterized by spectroscopic methods. Two phase transfer catalysts and three molar ratios NaOH/diphenol were used, and the results evaluated by the yields and the inherent viscosity va...
Novel polyamide-imides were prepared from 3′,4′-dicarboxy-4″-chloroformyl terephthaloylphenone anhydride and various aromatic and aliphatic diamines. The polymers were characterized by viscosity, infrared spectra, TGA, DSC, and elemental analysis. The thermal stability of the films was comparable to that of polyamide-imides previously reported.
Poly(carbonates) derived from diphenols that contain Si or Ge and bisphenol A bis(chloroformate) have been synthesized using phase-transfer conditions. The products were characterized by spectroscopic methods. Two phase-transfer catalysts and three molar ratios of NaOH/diphenol were used. The results were evaluated by the yields of product and thei...
Poly(esters) containing two heteroatoms, Si or Ge, in the main chain, derived from diphenols bis(4-hydroxyphenyl)-dimethyl-germane, bis(4-hydroxyphenyl)-diphenyl-germane, bis(4-hydroxyphenyl)-dimethyl-silane and bis(4-hydroxyphenyl)-diphenyl-silane, and the acid dichlorides bis(4-chloroformyl-phenyl)-dimethyl-germane, bis(4-chloroformyl-phenyl)-dip...
Organic light-emitting diodes were obtained using a thiophene vynilic derivative polymer electrochemically synthesized. The electrochemistry of the thiophene vynilic derivative, 1,5-bis(2-thienyl)-1,4-pentadien-3 one (CDV), was conducted in a nonaqueous media. The polymer was deposited on tin oxide (SnO2)-coated glass substrates. The films obtained...
The poly(ether-ester) derived from 4,4'-(1,5-naphthalenedioxy)-dibenzoic acid and bisphenol-A was synthesized under phase transfer conditions using quaternary ammonium salts as catalysts. The phase transfer process was effective showing an increase of the yields and m inh values with respect to those obtained without a catalyst. The best results we...
From the diphenol N-(2,6-diiodo-4-nitrophenyl)-3,3-bis(4-hydroxyphenyl)-butanamide, the synthesis of the poly(carbonate) with phosgene, the poly(thiocarbonate) with thiophosgene and the poly(ester)s with adipoyl chloride, isophthaloyl chloride and terephthaloyl chloride are described under phase transfer conditions using several quaternary ammonium...
The initiation of the electrochemical growth of polythiophene thin films was studied by X-ray photoelectron spectroscopy (XPS), electron probe micro analysis (EPMA), and mainly by scanning electron microscopy (SEM). The films were deposited on SnO2-coated glass in a classical three-electrode cell. Depositions were done under pure argon atmosphere....
It has been shown that thin insulating film at the interface transparent conductive oxide/organic electroluminescent film could improve the performance of organic electroluminescent diodes (OLED). Such insulating film can be inorganic or organic. Poly-(tetrabromo-p-phenylenediselenide) (PBrPDSe) has been proved to be an efficient insulating film in...
Polycarbazole (PCZ) thin films have been electrochemically synthesized on SnO2 coated glass substrates. The electrolyte used was the anhydric LiClO4. It is shown that, after optimization of the potential scanning domain, PCZ films are systematically obtained. The physical and morphological properties of films are described. The films obtained with...
The thermal properties of poly(esters) containing silicon or germanium in the main chain and derived from the diphenols bis(4-hydroxyphenyl)-diphenylsilane and bis(4hydroxyphenyl)-diphenylgermane and isophthaloyl or terephthaloyl acid dichlorides were studied by differential scanning calorimetry and dynamic thermogravimetry. Poly(esters) derived fr...
A serie of thiophene derivatives having functional groups of different nature between 2 and 2' ring positions has been synthesized. Through ab-initio calculations using HF 631G basis, the geommetry was optimized and the atomic distribution of the electronic densities of each neutral molecules were determined. It was found that the electronic densit...
The synthesis of poly(2,5-selenophen-oxo-1,4-phenylen-selenide-1,4-phenylene-oxo) (I) and poly(2,5-selenophen-oxo-1,4-phenylen-diselenide-1,4-phenylen-oxo) (II) by reaction of 2,5-bis(1,4-bromo-phenylen-oxo-)-selenophene with sodium selenide or diselenide, respectively, using dimethylformamide as solvent, is described. Both monomers and polymers we...
Polyarylureas were synthesized from the reaction between phosgene with aromatic diamines. Depending on the pH, the polyarylureas presented different colors when the solvent used was pyridine. The polyarylureas were characterized by IR spectroscopy, elemental analysis, and X-ray photoelectron spectroscopy (XPS). To study the thermal stability of the...
Poly(tetrabromo-p-phenylenediselenide) (PBrPDSe) has been doped by IBr, H2SO3, and CH3COOH acids. The samples have been studied by X-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR). Conductivity measurements have also been performed on pressed pellet samples. It has been shown by XPS and ESR that, after doping, positive charg...
The thermal behaviour of poly(amide-ester)s with the amide group in the side chain was studied. Polymers were sinthesized from the diphenol-amides N-(2,6-dichloro-4-nitrophenyl)-2, 2-bis(4-hydroxyphenyl)-propanamide, N-(2, 6-dichloro-4-nitrophenyl)-3,3-bis(4-hydroxyphenyl)-butanamide, and N-(2,6-dichloro-4-nitrophenyl)-4, 4-bis(4-hydroxyphenyl)-pen...