Electrodeposition of polyaniline nanostructures: A lamellar structure (original) (raw)
… of Nanoscience and …, 2009
Potentiodynamic electrochemical synthesis was used to controllably synthesize nanofibers (mean diameter 48 nm) and/or nanoparticles (mean diameter 88 nm) of polyaniline (PANI) on gold electrodes. The films were characterized by cyclic voltammetry (CV), field emission gun scanning electron microscopy (FEG-SEM) and atomic force microscopy (AFM). The type and dimensions of the nanostructures depend on deposition conditions such as monomer concentration and scan rate. This study shows that the nucleation and growth steps play a key role on the film development and its nano-morphology.
Electrochemical Synthesis of Polyaniline Nanoparticles and Nanofibers
2006
The electrochemical deposition of polyaniline nanofibers and nanoparticles have been investigated on gold electrodes by cyclic voltammetry and their morphology by high resolution scanning electron microscopy and atomic force microscopy. The type and dimensions of the nanostructures obtained depend on deposition conditions such as monomer concentration, scan rate and electrical potential. We have observed that the nucleation and growth steps play a key role on the film growth and its nano-morphology.
Polyaniline Thin Film Prepared by Electrochemical Polymerization Method
Biointerface Research in Applied Chemistry, 2021
Polyaniline (PANI) slim film was set up by electrochemical polymerization strategy at room temperature in a standard three-electrode cell from (0.1M) aniline monomer and (0,5M) from Sulfuric acid in the presence of distilled water. The development of PANI film was portrayed by Voltammetric studies, SEM, XRD, and FTIR. Voltammetric studies were performed in 0.5 M acidic aqueous solutions using H2SO4. The XRD design demonstrated that the diffraction top at 2θ = (30˚). The FTIR spectroscopy spectra give particular and unmistakable bonds at 3500, 1572.52, 1302.53, 831.98, and 592.85 cm-1.
Polyaniline nanostructures and the role of aniline oligomers in their formation
Progress in Polymer Science, 2010
Polyaniline (PANI) is prepared by the oxidation of aniline. Depending on the acidity conditions during the chemical oxidation, different types of products can be identified. The aniline dimers, semidines, are the first oxidation products. In the next step, aniline trimers containing a phenazine moiety, the nucleates, are produced. At moderate acidity, pH > 3.5, the reaction pathway further leads to higher brown non-conducting aniline oligomers. Alternatively, when the acidity is sufficiently high, pH < 2.5, the nucleates convert to initiation centers that start the subsequent propagation of PANI chains. The model of phenazine nucleates is offered to explain the various supramolecular nanostructures produced by PANI. It is proposed that the hydrophobic nucleates randomly aggregate in the aqueous phase or become organized to form one-dimensional stacks stabilized byinteractions. This step is followed by the growth of PANI chains from the self-assembled nucleates. The evolution of the nanostructures is conveniently observed by the combination of microscopic and spectroscopic techniques. The random agglomeration of nucleates gives rise to PANI granules and regular self-assembly into stacks subsequently leads to PANI nanofibers. The growth of other nanostructures requires a starting template. A model of a flowing template combined with a helical nanotubular growth is proposed to account for the formation of nanotubes, monomer droplets serve as templates for microspheres. The detailed chemical structure of nucleates has still to be elucidated. The nucleates adsorb and self-assemble along various interfaces giving subsequently rise to additional conducting polymer morphologies. The adsorption of nucleates at solid surfaces immersed in the reaction mixture leads to PANI nanofilms or coatings of various substrates. The competition between nucleate adsorption and nucleate self-assembly may lead to more complex morphologies combining one-dimensional and three-dimensional features, such as nanobrushes, hairy spheres, etc. The control of nucleates self-assembly and of PANI growth, the involvement of various interfaces in this process, and the role of PANI conductivity are discussed. The nanostructures produced by other conducting polymers, especially by substituted PANI, polypyrrole, or poly(3,4-ethylenedioxythiophene) are also considered. Two potential extensions to the preparation of related materials, such as nitrogen-containing carbonized PANI nanostructures or the composites of conducting polymers with noble metals are outlined. The present review accounts for the latest development in the realm of PANI nanostructures in past few years and provides an upgrade in the models proposed for their formation.
Effect of temperature on the electrochemical synthesis and properties of polyaniline films
Journal of Non-Crystalline Solids, 2010
The effect of temperature on the electrochemical oxidative polymerization of aniline and on the electrochemical properties of the resulting polyaniline (PANI) film was studied. The electrochemical deposition of PANI has been carried out on platinum at different temperatures. Three different films (PANI-25, PANI-40 and PANI-60) have been prepared at 25, 40 and 60°C by electrochemical polymerization and characterized by cyclic voltammetry and electrochemical impedance spectroscopy. Increasing the synthesis temperature leads to an increase of the polyaniline films thickness from 0.4 to 0.9 lm and, respectively, 1.1 lm, associated with an increase of the films capacitances from 3 Â 10 À2 F cm À2 to 7 Â 10 À2 F cm À2 and 10 Â 10 À2 F cm À2 . The impedance measurements showed that only PANI-25 and PANI-40 exist in the conductive state over a large potential window, while PANI-60 has an intermediate behavior at low and high electrode potentials.
Study of the Electrical Characteristics of Polyaniline Prepeared by Electrochemical Polymerization
Energy Procedia, 2012
Polyaniline (PAni) is one of imported polymer for synthesis solar cells .The quality of film depended on the method of polymerization. In this research PAni have been prepared by the electrochemical polymerization of aniline on stainless steel electrode. The electrical conductivity of these films was measured by two-probe method .The electrical conductivity is influenced by preparation conduction such as concentration of H 2 SO 4 and current density .The conductivity between (0.1 -10 -10 ) S/cm depends on PH and current density . The best electrical conductivity about (0.1) S/cm was found PH at (4.2) and current density 0.3mA/cm2.
Electropolymerization of polyaniline thin films
High Performance Polymers, 2014
Polyaniline (PANI) thin films have been electrochemically synthesized onto conducting glass substrates. The current study demonstrates that the properties of PANI films depend on the concentration of dopant acid. Well-adherent PANI coatings were obtained under potentiodynamic conditions during sequential scanning of the potential region between −0.35 V and +1.7 V with respect to silver/silver chloride. The structural, optical, and morphological properties of PANI films were studied with the aid of X-ray diffraction (XRD), Raman spectroscopy, ultraviolet–visible (UV-Vis) absorption spectroscopy, photoluminescence (PL) spectroscopy, and field-emission scanning electron microscopy (FESEM). Current–voltage ( I- V) measurements were performed to study the electrical properties of PANI films. The XRD peaks observed at 2 θ = 15.4°, 24.2°, and 25.1° confirm the synthesis of emeraldine form of PANI. The strong absorption peaks observed in the UV-Vis absorption spectra at 317 nm (π–π* interba...
Chemical and electrochemical synthesis of polyaniline micro- and nano-tubules
Synthetic Metals, 2000
The synthesis of polyaniline/platinum composites (PANI/Pt) has been achieved using both chemical and electrochemical methods. The direct chemical synthesis of PANI/Pt proceeds through the oxidation of aniline by PtCl 6 2− in the absence of a secondary oxidant. SEM images of these samples indicate that the Pt particles are on the order of ∼1 m for the chemically prepared composite. Electrochemical PANI/Pt synthesis is initiated by the uptake and reduction of PtCl 6 2− into an a priori electrochemically deposited PANI film. This method produces a uniform dispersion of Pt particles with smaller particles with diameters ranging between 200 nm and 1 m. The results indicate that electrochemical methods may be more suitable for controlling particle dimension. Both materials show reduced proton doping relative to PANI without Pt, indicating the metal particles directly influence proton doping and the oxidation state of the polymer. The electrochemical data indicate that the conductivity in solution is sufficient such that the normal acid doping is attainable for PANI/Pt produced using either synthetic method.
Novel approach to the synthesis of polyaniline possessing electroactivity at neutral pH
Synthetic Metals, 2019
A new approach is proposed for the synthesis of polyaniline via electrochemical polymerization of aniline at a very low concentration on a modified electrode surface. The electrode was modified with a sulfonated polyaniline, poly(2-methoxy aniline-5-sulfonic acid) (PMAS), which acted as an electroactive conductive template for the aniline monomer. The electrode surface was modified with PMAS via a number of different methods including cyclic voltammetric and potentiostatic deposition as well as dip and drop casting water-soluble PMAS onto the electrode surface. Electrochemical polymerization of aniline was then carried out at the surface of the modified electrode. Effect of different variables such as PMAS concentration, volume and pretreatment of the modified electrode on the polymerization of aniline was studied. The polymer synthesized at the PMAS modified electrode was characterized by electrochemical and UV-vis spectrophotometic techniques. Electrochemical studies showed that even at very low concentration of aniline (5.0 mM), an adherent, uniform and stable polyaniline film was deposited on the electrode surface. Without any further treatment, this polyaniline layer was found to be electroactive at a neutral pH which is crucial for biosensing applications.