Studies on poly(diphenylamine) synthesized electrochemically in nonaqueous media (original) (raw)
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Journal of Macromolecular Science, Part A, 2012
Poly(diphenylamine) has been synthesized electrochemically under galvanostatic condition in nonaqueous acetonitrile media at different monomer concentrations. The UV±Vis spectra reveals the selective formation of conducting phase $840 nm at a low monomer concentration of 0.05 M. An increase in monomer concentration to 0.1 and 0.4 M leads to a loss in selectivity in the formation of conducting phase (especially at a higher time interval). The characteristics observed in the IR absorption spectra are in accordance with those obtained in the UV±Vis spectra. Morphology of the ®lms exhibit a change over from ®brillar to granular type on going from a monomer concentration of 0.05 to 0.4 M. The effect of monomer concentration on the redox properties of diphenyl amine and poly(diphenylamine) are investigated using a cyclic voltammetric technique. On comparing the two sets of cyclic voltammograms, a shift in peak potential is observed. From the thermal analysis it is found that the loss in second step is greater at lower monomer concentration due to predominant formation of conducting phase. # 1999 Elsevier Science S.A. All rights reserved.
Polymer Journal, 1998
Two kinds of films, named A and B, ofpolydiphenylamine (PDPA) electrochemically synthesized have been characterized by ex situ resonance Raman, FT-IR and UV-Vis-NIR Reflectance spectroscopies. The ex situ RR spectra of the films showed differences, that were rationalized assuming the predominance of the diphenosemiquinone aminoimine structure in the film A, while in the film B the diphenoquinone diimine segments were predominant. The variation of the nature of the film adsorbed on the electrode with the applied potential has been monitored by means of the in situ resonance Raman technique. The bands characteristics of the diphenosemiquinone aminoimine moiety are dependent on the laser power employed, being converted to diphenoquinone diimine and diphenyl diamine segments. This result was confirmed by FT-IR spectra of the film A after heating. The thermal behavior of the films was monitored by thermogravimetry (TG), derivative thermogravimetry (DTG), and differential scanning calorimetry (DSC).
Electrochemical synthesis of electroactive polytriphenylamine
Synthetic Metals, 2000
In this paper the electrochemical synthesis of polytriphenylamine is shown for the first time. The electrochemical oxidation of Ž . triphenylamine TPA in nonpolar solvents leads to the formation of oligomers of TPA in solution and the formation of a polymer film with TPA as repeating unit. Cyclic voltammetry of these electrochemically produced TPA films is compared to that of chemically produced polytriphenylamine what demonstrates a similar electrochemical behaviour. From FTIR spectra of the polymer film it is concluded that the electrochemically formed polymer is more crosslinked than the chemically produced one. Therefore, it is a very stable redox polymer and a promising candidate for application in batteries, electrochromic displays, sensors or organic electronic devices. q
Deposition, growth processes and characterization of poly(diphenylamine-co- N-methyl aniline
Thin Solid Films, 2004
Copolymerization of diphenylamine (DPA) with N-methyl aniline (NMA) was carried out in aqueous sulfuric acid medium by pulse potentiostatic method (PPSM). The copolymer film was grown on the surface of the working (platinum) electrode for various experimental conditions and the charge associated with film deposition was followed by cyclic voltammetry. The charge values were correlated to the amount of copolymer deposition (growth) and amount of copolymer deposited per unit time of electropolymerization (growth rate). The kinetics of the electrochemical copolymerization was followed by deducing the growth and growth rate equations in terms of charge associated with the film deposition and the conditions of electropolymerization. The deduced growth and growth rate functions indicate the dependences of concentration of DPA and NMA. The copolymer was also synthesized through oxidative polymerization and characterized by conductivity measurement, Fourier transform infra-red spectroscopy, nuclear magnetic resonance spectroscopy, ultra violet-visible spectroscopic techniques and thermogravimetric analysis. ᮊ
Electrochemical synthesis and study of polydiphenylamine
Journal of Electroanalytical Chemistry, 1987
The electrochemical oxidation of diphenylamine in acetonitrile produces an adherent conducting polymer film at the electrode. Conductivity measurements on pressed pellets of this polymer give a room temperature conductivity of 10 S cm-'. The polymer can be cycled between 25 and 2OO'C without deterioration in the conductivity. Preliminary SEM/EDS studies suggest that there is one BFi counter ion for every four monomer units in the oxidised polymer film. 0022-0728/87/$03.50 0 1987 Elsevier Sequoia S.A.
Journal of Applied Electrochemistry, 1988
Theory is presented for the interpretation of cyclic voltammetric and chronoamperometric measurements made on electrodes modified by being covered with an insoluble layer of a polymer containing electroactive pendant groups. It is assumed that the redox behaviour of the film is non-ideal and that the activity coefficients of the components of the redox couple can be reasonably modelled by regular solution theory. In this way non-ideal behaviour is interpreted in terms of a single 'interaction parameter'. It is found that a wide range of cyclic voltammograms for diverse polymer systems reported in the literature can be thus very satisfactorily described. We also report the synthesis of the novel polymer poly(4-vinyl-triphenylamine), PVTPA, and describe and interpret the behaviour of electrodes coated with this polymer during electro-oxidation in acetonitrile solution. Excellent agreement with the regular solution theory is found. Chronoamperometric data for the related polymer poly(4-vinyl-4',4"-dibromotriphenylamine) is also reported and found to give good agreement with the theory.
Helvetica Chimica Acta, 2008
The substituted monomers 4a,c,d, 5a,b, 6a, 7a,b, and 8a of novel poly(diphenylamines), possessing the respective photochromic groups, were synthesized by the Stille cross-coupling methodology (Scheme). The hyperbranched structures were characterized by 1H- and 13C-NMR spectroscopy. The obtained monomers show good stability in common organic solvents such as CHCl3, toluene, and CH2Cl2, and exhibit excellent thermal stability. Electrochemical results and theoretical calculations suggest that oxidation and reduction of the monomers start from the side of the amine function and the five-membered heterocyclic ring moieties, respectively.
Journal of Solid State Electrochemistry, 2002
Triphenylamine was electrochemically polymerized in a mixture of toluene and acetonitrile with different electrolyte salts. The poly(triphenylamine) (PTPA) films are insoluble in polar solvents and show high stability and no degradation or loss in electrochemical properties when stored in a laboratory atmosphere. The PTPA films were characterized in situ by FTIR external reflection spectroscopy and by Raman spectroscopy.
Electrochromism and electrochemical characterization of soluble poly[3-alkylhetero(arylene)s]
Solar Energy Materials and Solar Cells, 1992
Soluble conducting poly[3-alkylhetero(arylene)s] have been prepared electrochemically from 3-alkylheteroarylene monomers. Optical conditions for the electrochemical polymerization were in acetonitrile and tetrabutylammonium hexafluorophosphate (Bu4NPF 6) as the solvent and the electrolyte, respectively. Two oxidation potential values (Eox) were exhibited in the ranges 0.75-1.12 V and 1.86-2.02 V versus Ag/AgCI, respectively. On the other hand, the polymer oxidation potentials (Epo x) in monomer-free solution were 1.34-1.42 V versus Ag/AgCI. The electrochemical data of these compounds are compared with those of poly(3-methylthiophene), polythiophene and their derivatives prepared under the same polymerization conditions. The conductivities of the electrochemically grown films were measured using the four-probe technique before and after exposure to doping agents. The values for the conductivities (or) of the "as-grown" films were in the order of = 10-2-10 1) -x cm -x. The infrared (IR) and nuclear magnetic resonance (NMR) spectra of these polymers indicated that the bonding of the monomer units are mainly 2,5 linkages. Solubility tests of these polymers are also given. Thin films formed under constant current density of 1 mA cm -2 (galvanostatically) or cast by evaporation of the solvent on optically transparent electrodes (OTE) displayed electrochromic properties. The film colors are dark blue and brick red in the oxidized (doped) and in the neutral (undoped) states, respectively. The formal potentials (E °') and n values of the polymer films are reported. The E °' values of the films in the monomer-free solution were 0.73-0.96 V versus Ag/AgCI. These values were compared to the (Eoo x) values from the cyclic voltammetric technique for the same polymer films. The fluorescence spectra of the polymer solutions in different solvents showed an intense broad emission band at --410-660 nm.
Low potential electrochemical polymerization of diphenyl ether and characterization of its polymers
Journal of Polymer Science Part A-polymer Chemistry, 2007
High-quality poly(diphenyl ether) (PDPE) films with electrical conductivity of 4.4 × 10−1 S cm−1 were synthesized electrochemically by direct anodic oxidation of diphenyl ether (DPE) in boron trifluoride diethyl etherate (BFEE) containing 5% concentrated sulfuric acid (SA) (by volume). The oxidation potential onset of DPE in pure BFEE was measured to be only 1.37 V versus a saturated calomel electrode (SCE), which was much lower than that determined in acetonitrile + 0.1 mol L−1 tetrabutylammonium tetrafluoroborate (1.98 V vs. SCE). The addition of SA to BFEE can further decrease the oxidation potential onset of the monomer to 1.18 V versus SCE in the mixed electrolyte of BFEE + 5% SA. PDPE films obtained from this medium showed good redox activity and stability even in concentrated SA. Dedoped PDPE films were partly soluble in the strong polar organic solvent dimethyl sulfoxide. Fluorescent spectral studies indicated that soluble PDPE was a good blue-light emitter with a quantum yield of 0.30. Infrared spectroscopy and quantum chemistry calculations indicated that the electropolymerization of DPE occurred mainly at C4 and C4′. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5932–5941, 2007