Sharif Digital Repository

A glassy carbon electrode (GCE) was modified with a thin layer of multiwalled carbon nanotubes (MWCNTs) and subsequently, electrochemically deposited poly-pyrrole. The electrochemical behavior of mesalazine was studied on the surface of the modified electrode by applying linear sweep voltammetry (LSV). The electropolymerization process and the electrochemical response toward mesalazine were investigated in the presence of different aromatic anion dopants including, benzenesulfonic acid (BSA), 1,3-benzenedisulfonic acid (1,3-BDSA), 1,5-naphthalenedisulfonic acid (1,5-NDSA) and new coccine (NC). By using 1,5-NDSA as dopant, a significant increase (~418 times) in the peak current of mesalazine... 

A new sensitive electrochemical sensor was fabricated based on a layer by layer process. In this process the glassy carbon electrode (GCE) is first coated by a thin film of multiwalled carbon nanotubes (MWCNTs). In the next step, the electropolymerization of pyrrole in the presence of Nitrazine Yellow (NY) as a dopant anion is performed on the surface of the MWCNTs precoated electrode. The electrochemical response characteristics of the modified electrode toward naltrexone (NTX) were studied by means of linear sweep voltammetry (LSV). A remarkable increase (~19 times) was observed in the anodic peak current of NTX on the surface of the modified electrode relative to the bare GCE. The effects... 

A composite surface coating is prepared by electropolymerization of a mixture of pyrrole and carbon nanoparticles onto a glassy carbon electrode (GCE). The microscopic structure and morphology of the composite film is characterized by scanning electron microscopy. The modified electrode offers a considerable improvement in voltammetric sensitivity toward methyldopa (m-dopa), compared to the bare and polypyrrole-coated GCEs. A significantly enhanced anodic peak current together with a remarkable increase in sharpness of the cyclic voltammetric (CV) signals are observed for the detection of m-dopa. The effect of experimental parameters, such as scan rate and pH, are investigated by monitoring... 

Two different ternary nanocomposites, PPy/CNT/CoFe2O4 and PPy/CNT/NiFe2O4, were synthesized by in situ polymerization method. The resulting composites were characterized using Fourier transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction. They were evaluated with the aim of investigating microwave absorption properties. The results showed that the value of microwave reflection decreases as that of prepared nanocomposites increases. This happens with increase in the PPy content and polymerization on the surface. © 2018 Académie des sciences  

The electrosynthesis of polypyrrole (PPy) film has been achieved on glassy carbon electrode (GCE) in aqueous medium of Congo red (CR) by means of cyclic voltammetry (CV). The modified electrode exhibits high electrocatalytic activity toward dopamine (DA) oxidation, with drastic enhancement of the reversibility and peak currents. This modified electrode, due to electrostatic interactions, is capable to mask the response of ascorbic acid (AA) completely and provide an effective method for the detection of minor amounts of dopamine in the presence of high concentrations of AA. The electrochemical response of the film modified electrode is strongly dependent to the switching potential applied in... 

A pyrrole-based conductive polymer was prepared and applied as new sorbent for on-line solid-phase extraction (SPE) of phenol and chlorophenols from water samples. Polypyrrole (PPy) was synthesized by chemical oxidation of the monomer in non-aqueous solution. The efficiency of this polymer for extraction of phenol and chlorophenols was evaluated using 35 mg of PPy as the sorbent in an on-line SPE system coupled to reversed-phase liquid chromatography with UV detection. The mobile phase were mixture of phosphate buffer-acetonitrile and compounds were eluted by the mobile phase using a six-port switching valve. High volumes of water, up to 160 ml, could be preconcentrated without the loss of... 

A pyrrole-based polymer was synthesized and applied as a new sorbent for solid-phase extraction (SPE) of some environmental pollutants from water samples. Polypyrrole (PPy) was synthesized by chemical oxidation of the monomer in nonaqueous solution. SPE of selected phenols, pesticides, and polyaromatic hydrocarbons (PAHs) from aqueous samples were performed using 200mg PPy. The determination was subsequently carried out by gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The polymer showed much higher recoveries for aromatic compounds than aliphatics. Preconcentration of sample volumes up 1l led to acceptable recoveries for aromatic and... 

A micro-solid phase extraction technique was developed using a novel polypyrrole-polyamide nanofiber sheet, fabricated by electrospinning method. The applicability of the new nanofiber sheet was examined as an extracting medium to isolate malathion as a model pesticide from aqueous samples. Solvent desorption was subsequently performed in a microvial, and an aliquot of extractant was injected into gas chromatography-mass spectrometry. Various parameters affecting the electrospinning process including monomer concentration, polyamide content, applied voltage, and electrospinning time were examined. After fabricating the most suitable preparation conditions, influential parameters on the... 

We describe a nanocomposite prepared from polydopamine, silver nanoparticles, and polypyrrole (PDA-Ag-PPy) that can be used for the microextraction in packed syringe (MEPS) of tricyclic antidepressants from urine samples. The PDA-Ag-PPy composite was prepared in-situ by the reduction of silver ion - doped PPy during oxidative polymerization of dopamine. The PDA-Ag coatings on the nanoribbon – shaped PPy represent a highly porous, inorganic–organic hybrid nanomaterial that has a wide range of applications. The nanocomposite was characterized by FTIR and scanning electron microscopy. It is shown to be an efficient sorbent for the MEPS of the tricyclic antidepressants amitriptyline, imipramine... 

A novel amperometric non-enzymatic glucose sensor is designed by the facile preparation method. It is made by electrodeposition of Cu clusters and converting them to Cu(OH)2 nanotubes (Cu(OH)2NTs) arrays along with thin-film electro-polymerized of spindle-shaped polypyrrole (PPy@Cu(OH)2NTs), which have been doped by using sodium Benzene-1,3-disulfonate as an anion dopant. Various electrochemical methods investigate the electrochemical performance of the modified electrode toward glucose detection. Under the optimized conditions, a significant electrochemical response improvement is observed toward the electro-oxidation of glucose on the PPy@Cu(OH)2NTs electrode's surface relative to the... 

A new micro-solid phase extraction method was developed by combining solid-phase extraction and stir bar sorptive extraction to benefit from the advantages of both techniques. A polypyrrole coating was electrochemically synthesized on the surface of an already used graphite furnace, employed in electro-thermal atomic absorption spectroscopy. The cylindrical geometry of the graphite tube provided a rather huge surface area, suitable for sorptive extraction. The novel sorbent coating was examined as an extracting medium to isolate malathion. Effects of different parameters such as extraction time, salt concentration, sample volume, desorption solvent and time were investigated and optimized.... 

Co-free Li-rich manganese nickel oxide (LMNO) materials are emerging as an up-and-coming candidate for high-energy–density cathodes. However, they suffer from severe cycling capacity fading and poor performance rates. Herein, the surface functionalization of an LMNO cathode is designed by polypyrrole (PPy) nanostructure coating. We found that PPy nanoparticles@LMNO cathode exhibits high-capacity retention and enhanced rate capabilities, delivering a discharge capacity as high as 191 mAh g−1, with capacity retention of 96%, after ∼ 200 cycles at a current density of 20 mA g−1. The results indicate that the intercalation and doping pseudocapacitance can be varied depending on the synthesis... 

In this paper, nano/microstructured-conducting polypyrrole has been prepared on Cu/Au interdigital electrode surfaces by using constant potential amperometry technique. The Fe(II) ions were used as catalyst and X = ClO4 -, pTs-, Cl-, TCA-, DS-, DBS- was implemented as anion dopants. The morphologies of the films were investigated by field emission scanning electron microscope. A remarkable dependence was observed between the type of anion dopant and the morphology of polypyrrole (PPy). The sensing behavior of the PPy-X sensor has been studied toward acetone, methanol, ethanol, 1-propanol, 2-propanol, nitromethane, propylamine, pyridine, and gas mixtures of aliphatic alcohols. The responses... 

Designing a novel epoxy composite system with dual self-healing/barrier anti-corrosion functions using graphene oxide (GO) nano-platforms decorated by polypyrrole (PPy) nanoparticles doped with zinc metal ions is the major objective of this research attempt. GO-PPy-Zn nanoplatform was fabricated via one-pot polymerization of pyrrole monomers on GO and two direct/indirect methods of zinc doping. In order to verify the PPy nanoparticles synthesis on GO sheets several analyses such as UV–visible, XPS, HR-TEM and FE-SEM were performed. The epoxy nanocomposite coatings containing GO-PPy and GO-PPy-Zn nanoplatforms were fabricated and applied on carbon steel. The nanocomposite coatings... 

The morphology of the perovskite layer, the effective extraction of the charge carriers, and their transport are the main factors determining the power conversion efficiency (PCE) of the perovskite solar cells (PSCs). In this work, we demonstrated that the geometric and electronic structures of the PSCs could be modified by using a conductive polymer additive in the lead (Pb) halide layer prepared by a two-step deposition method. Polypyrrole (PPy) as a conductive polymer is used in the perovskite layers which could increase the PCE of CH3NH3PbI3-xClx mixed-halide PSCs. By adding an optimized amount of PPy, PCE has been raised from 10.4 to 13.2%. PPy acts as a conductive channel facilitating...