Preparation Of Polypyrrole Research Articles

Protein adsorption materials based on conducting polymers: polypyrrole modified with ω‐(N‐pyrrolyl)‐octylthiol

AbstractIn order to fabricate a new polymer matrix for application in biochips and to understand the mechanism of adsorption of proteins on conducting polymers, we prepared polypyrrole (PPy) functionalized with ω‐(N‐pyrrolyl)‐octylthiol moieties. The chemical structure of the polymer could be controlled by varying the concentration of pyrrole added as the monomer. Initially, ω‐(N‐pyrrolyl)‐octylthiol was self‐assembled into a monolayer on a gold surface. Thereafter, a layer of uniform and smooth PPy was obtained by the chemical copolymerization of pyrrole and the ω‐(N‐pyrrolyl)‐octylthiol. Bovine serum albumin (BSA) adsorption on the polymer was investigated using surface plasmon resonance spectroscopy and cyclic voltammograms. The chemical structure and monomer components of the as‐prepared films were characterized using Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy. Water contact angle measurements were used to assess the surface wettability of the films throughout the preparative procedure. The kinetics of BSA adsorption onto the polymer could be controlled by varying the copolymer thickness and the pH value of the buffer solutions used. Moreover, the electroactivity was changed upon BSA binding. The results suggest that the new conducting polymer may potentially be applied as a more sensitive and reliable matrix in protein sensors. Copyright © 2011 Society of Chemical Industry

Preparation of polypyrrole by direct electrochemical oxidation of pyrrole on paraffin impregnated graphite electrode

The formation of polypyrrole (PPy) layers by electrochemical polymerisation of pyrrole (Py) on paraffin impregnated graphite electrode (PIGE) was studied. Electrochemical oxidation of Py was studied by means of cyclic voltammetry (CV) and the morphology of the deposited layers was investigated with scanning electron microscope (SEM). The structure and quality of PPy layers on PIGE depends on monomer concentration, pH value, stirring intensity and scan rate during the polymerisation process.

Preparation and characterization of microporous fibers for sample preparation and LC‐MS determination of drugs

The aim of this study was the preparation of polypyrrole (PPy) fibers for solid phase microextraction (SPME). PPy coatings were obtained during the electrochemical polymerization process. The utility of various metal wires (Fe, Cu, Ag, Cu/Ag, kanthal and medical stainless steel) as a support for polymers was compared. Various experimental conditions of the synthesis process such as scan rate, voltage limits and number of scans and deposition time were applied. The average polymer thickness was in the range of 7-125 microm and its weight was in the scope of 0.65-5.6 mg. Different techniques, mainly elemental analysis, Fourier transform infrared spectroscopy, microscopy, and chromatography were performed for the characterization of obtained fibers with microporous structure. The extraction efficiency of cardiovascular drugs (metoprolol, propranolol, oxprenolol, propafenone and mexiletine) by means of fibers was tested. The concentration of mentioned compounds in standard solution was in the span of 10-150 ng/mL. LC-MS was employed for determination of drugs in desorption solution. LODs varied from 0.013 to 1.51 ng/mL for metoprolol and mexiletine respectively. The repeatability of extraction was obtained with the RSD values lower than 10%.

Preparation of polypyrrole-graft -poly(N -isopropylacrylamide)/silver nanocomposites from pyrrolyl-capped macromonomer by AgNO3 and their stimuli responsibility of light emission

Pyrrolyl-capped poly(N-isopropylacrylamide) macromonomers (Py-PNIPAM) were prepared through reversible addition-fragmentation-transfer polymerization with benzyl 1-pyrrolylcarbodithioate as chain-transfer agent. Polymerizations of Py-PNIPAM with/without pyrrole using AgNO3 as oxidizing agent and dimethylforamide as solvent resulted in graft copolymers of polypyrrole-graft-poly(N-isopropylacrylamide) (PPy-g-PNIPAM) as well as silver nanoparticles, leading to the formation of PPy-g-PNIPAM/silver nanocomposites. The resulting nanocomposites were soluble in water when the content of PPy was low, and when the molar ratio of Py/Py-PNIPAM increased to 30, the resulting products became insoluble in water. The resulting nanocomposites had special optical properties because of PPy as well as the temperature-responsible PNIPAM. The chemical structure and composition of nanocomposite were characterized by 1H nuclear magnetic resonance spectroscopy, gel permeation chromatograms, fourier transform infrared spectroscopy, and X-ray diffraction. Their optical properties were characterized by UV–vis and fluorescence spectroscopy. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6950–6960, 2008

Preparation of Polypyrrole/ Nano-TiO2 Composite by the Potential Cycling Method

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Effect of polymerization time on the humidity sensing properties of polypyrrole

In this paper, we prepared polypyrrole (PPY) films using a chemical method at different polymerization times. Their structure and morphology were characterized through X-Ray powder diffraction (XRD), IR, and scanning electron microscope (SEM). The humidity sensors were made by a coating membrane method. We studied the humidity sensing properties of the PPY- x films (the letter ‘ x’ denotes the polymerization time and it was 4, 24, or 96 h). It was found that the humidity sensing properties of PPY could be improved greatly by extending the polymerization time. According to our experiment results, we predict that the humidity sensing properties of conducting polymers could be improved by increasing their crystallinity degree.

REMOVAL OF MERCURY FROM WATER USING POLYPYRROLE AND ITS COMPOSITES

One of the suitable methods for removing heavy metals from water is by using surface adsorption process. In this paper, the preparation of polypyrrole and its composites as adsorbents are discussed and the capability of separating mercury from water is investigated. The results indicated that the polypyrrole and its composites are able to remove mercury from aqueous media. Furthermore the adsorption percentage is related to the surface morphology, type of additives and its concentration.

One-pot synthesis of polypyrrole film on an aluminum oxide layer by electropolymerization in the presence of ammonium borodisalicylate in acetonitrile

Abstract This paper describes how one-pot preparation of polypyrrole (PPy) on Al 2 O 3 layer in an aluminum solid capacitor could be achieved by electropolymerization of pyrrole (Py) in acetonitrile with small amounts of water, using ammonium borodisalicylate (ABS) as a new electrolyte. The effects of monomer and electrolyte concentrations, current density, and polymerization temperature on the PPy formation on Al 2 O 3 layer in aluminum solid are also discussed. Polymerization occurred smoothly to give PPy on the Al 2 O 3 layer under the following conditions: [ammonium borodisalicylate] = 0.02 M, [Py] = 0.1 M, and polymerization temperature = −42 °C, current density = 10 mA cm −2 . The normalized capacitance, the C p / C 0 value of capacitor fabricated, reached more than 0.9, indicating that the porosity and surface of the Al 2 O 3 layer are filled up and covered with PPy. The Raman spectra of the PPy film showed that the peak assignable to C C backbone stretching shifted to a lower wave number of 1585 cm −1 . This indicates formation of the film with well-conjugated C C backbone. The SEM micrograph of PPy on Al 2 O 3 layer showed a closely packed globular morphology. These results indicate that the new electrolyte, ABS, has an excellent ability to form PPy film directly on Al 2 O 3 surface by electropolymerization.

Preparation of Polypyrrole by Emulsion Polymerization Using Hydroxypropyl Cellulose

Polypyrrole with particles of uniform diameter was easily obtained from an emulsion of hydroxypropyl cellulose (HPC) and pyrrole by chemical oxidative polymerization, using iron chloride as an oxidizing agent. The particle diameter of the polypyrrole could be controlled by changing the HPC concentration, and it was found that the preparation of water-dispersible polypyrrole was possible. The conductivity of the polypyrrole particles was of the order of 10−1 S/cm.

Characterization and electrical properties of polypyrrole/multiwalled carbon nanotube composites synthesized by in situ chemical oxidative polymerization

AbstractThis study describes the preparation of polypyrrole (PPy)/multiwalled carbon nanotube (MWNT) composites by in situ chemical oxidative polymerization. Various ratios of MWNTs, which served as hard templates, were first dispersed in aqueous solutions with the surfactant cetyltrimethylammonium bromide to form micelle/MWNT templates and overcome the difficulty of MWNTs dispersing into insoluble solutions of pyrrole monomer, and PPy was then synthesized via in situ chemical oxidative polymerization on the surface of the templates. Raman spectroscopy, Fourier transform infrared (FTIR), field‐emission scanning electron microscopy (FESEM), and high‐resolution transmission electron microscopy (HRTEM) were used to characterize the structure and morphology of the fabricated composites. Structural analysis using FESEM and HRTEM showed that the PPy/MWNT composites were core (MWNT)–shell (PPy) tubular structures. Raman and FTIR spectra of the composites were almost identical to those of PPy, supporting the idea that MWNTs served as the core in the formation of a coaxial nanostructure for the composites. The conductivities of these PPy/MWNT composites were about 150% higher than those of PPy without MWNTs. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1413–1418, 2006

Fourier transform infrared study of polypyrrole–poly(vinyl alcohol) conducting polymer composite films: Evidence of film formation and characterization

AbstractThe electrochemical preparation of polypyrrole (PPY)–poly(vinyl alcohol) (PVA) conducting polymer composite films on an indium–tin oxide glass electrode from an aqueous solution containing a pyrrole monomer, a p‐toluene sulfonate electrolyte, and a PVA insulating polymer is reported. The prepared PPY–PVA composite films were characterized by Fourier Transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and conductivity measurements. The FTIR study showed that the composite of PPY and PVA formed through bond formation between PVA and the p‐toluene sulfonate dopant anion. The conductivity data of PPY–PVA showed that with increasing PVA concentration in the pyrrole solution, the conductivity of the prepared PPY–PVA film increased up to a certain level due to an increase in conjugation length, and later, it decreased with further increases in the PVA concentration in the solution due to a decrease in conjugation length. This was supported by the FTIR band intensity I1560/I1480. The TGA results show that the PPY–PVA polymer composite film was thermally more stable than the PPY film. A shielding effectiveness of 45.6 dB was exhibited by the PPY–PVA composite film in the microwave frequency range. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4107–4113, 2006

An effective layer-by-layer adsorption and polymerization method to the fabrication of polyoxometalate-polypyrrole nanoparticle ultrathin films

A layer-by-layer (LbL) adsorption and polymerization method was developed for the controllable preparation of polypyrrole (PPy) nanoparticles within ultrathin films. By repetitive adsorption of pyrrole and subsequent polymerization with 12-molybdophosphoric acid, the polyelectrolyte multilayer films containing PPy nanoparticles were fabricated. UV–visible absorption spectrocopy, Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM), transmission electron microscopy (TEM) and cyclic voltammograms (CVs) were used to characterize the PPy nanoparticles and their multilayer thin films. UV–visible spectra indicate that the growth of PPy nanoparticles was regular and occurred within the polyelectrolyte films. The size of prepared PPy nanoparticles was found by TEM to increase with the increasing of polymerization cycles. The electrochemistry behavior of the multilayer thin films was studied in detail on ITO. The results suggest that the LbL adsorption and polymerization method developed herein provides an effective way to prepare PPy nanoparticles in the polymer matrix.

Radiation and storage-induced ageing of polypyrrole doped with dodecylbenzene sulfonic acid

The effects of storage and exposure to X-rays on the surface chemistry of electrochemically prepared polypyrrole (PPy) doped with dodecylbenzene sulfonic acid (DBSA) were investigated using X-ray photoelectron spectroscopy (XPS). For irradiation, different photon sources (lab source and synchrotron radiation) and energies (1.4–9 keV) were chosen. This covers an energy range of relevance for many X-ray based investigations (e.g. XPS or X-ray absorption spectroscopy) of PPy[DBSA], PPy–metal interfaces, and transition metals embedded into PPy. The DBSA doping level and the concentration ratio of sulfonate species are discussed as a function of storage and irradiation times, and links between both ageing parameters are given. New sulfur species are found to emerge upon repeated soft X-ray irradiation. Severe changes in the polaron/bipolaron structure of PPy[DBSA] during exposure to high energy (several keV) synchrotron radiation are observed, and the results are discussed in the light of photon absorption and photoelectron generation in the polymer surface.

Vapor Phase Polymerization of Pyrrole and Thiophene Using Iron(III) Sulfonates as Oxidizing Agents

Vapor phase polymerization is a versatile technique that can be used to obtain highly conducting coatings of conjugated polymer on both conducting and nonconducting substrates. This is demonstrated here by preparation of polypyrrole, polybithiopene, and polyterthiopene, coatings that otherwise must be prepared electrochemically in order to achieve the desired high conjugation. The method is based on the use of organic ferric sulfonates as oxidant as these salts easily form smooth, noncrystalline films. By proper choice of the sulfonate anion, the oxidizing power of the ferric salt can be varied over a wide range. The described technique can easily be adapted to different patterning techniques.

Pyrrole self-assembled monolayer and orderly autopolymerization on chloride- and gold-containing nanocomplexes prepared by electrochemical methods

We report here the first electrochemical pathway to prepare Cl- and Au-containing nanocomplexes of mean diameter 2 nm in 0.1 M HCl aqueous solutions without the addition of any stabilizer. Based on these prepared nanocomplexes, pyrrole monomers can form self-assembled monolayers and further develop orderly spontaneous polymerization (called autopolymerization), which is distinguishable from conventional chemical or electrochemical polymerization, on these nanocomplexes. Furthermore, the prepared polypyrrole (PPy)-coated gold nanoparticles with a core-shell structure can be further treated with sonication for the preparation of Au(0) nanoparticles. This strategy provides another way to fabricate metal nanoparticles without the addition of any stabilizer.

Synthesis and VOC gas sensing properties of Polypyrrole / MoO3 Nanohybrids

ABSTRACTWe have prepared polypyrrole (PPy) / MoO3 nanohybrid thin films and evaluated their volatile organic compound (VOC) gas sensing properties. The (PPy)xMoO3 thin films have been prepared by intercalation reactions of highly oriented MoO3 thin films. Intercalation of hydrated sodium ions successfully proceeded without loosing the crystallographic orientation. The (PPy)xMoO3 thin films was obtained by replacing the hydrated sodium ions with PPy. The (PPy)xMoO3 thin films can detect formaldehyde gas by increasing in their electrical resistance, whereas they showed no response to toluene.

Conducting polymers as ion-exchangers for water purification

The charging and discharging processes of conducting polymers, e.g. polypyrrole, are accompanied by the exchange of ions. This effect was used for the development of an electrochemically switchable ion-exchanger for water purification, especially for softening drinking water. The ion-exchange behaviour and capacity of electrochemically and chemically prepared polypyrrole (PPy) in dependence on the incorporated counterions are characterised using an electrochemical quartz crystal microbalance and cyclovoltammetry. An ion-exchanger electrode based on modified PPy-nanoparticles was tested in a laboratory loop. The ion concentrations of the test solutions treated were investigated by atomic absorption spectroscopy and ion-selective electrodes with respect to an application for softening drinking water.

Technical application of conducting polymers for water treatment

Conducting polymers exhibit ion exchanger properties evoked by charging and discharging processes. The ion-exchange behaviour of electrochemically and chemically prepared polypyrrole (PPy) was investigated using electrochemical quartz crystal microbalance (EQCM) and ion-selective electrodes. An ion-exchanger electrode was prepared and tested in a laboratory loop considering the application of PPy as an electrochemically switchable ion-exchanger for water treatment.

Properties of chemically prepared polypyrrole with an aqueous solution containing Fe 2(SO 4) 3, a sulfonic surfactant and a phenol derivative

This paper describes chemically prepared polypyrrole (PPy) with an aqueous solution containing Fe 2(SO 4) 3 as an oxidant. PPy having enhanced conductivity and environmental stability was obtained under the coexistence of a sulfonic surfactant and a phenol derivative with an electron-withdrawing group. The effect of the sulfonic surfactant was ascribed to a large-sized sulfonic anion being selectively incorporated into PPy as dopant, because an increase in the yield of PPy depended on the concentration of the surfactant. For PPy synthesized with a solution containing p-nitrophenol (pNPh), a clear increase in the doping ratio was recognized from elemental analysis. Moreover, the conductivity of PPy increased with increasing strength of the electron-withdrawing force of the substituent. The electron-withdrawing substituent of the phenol derivative seems to prevent undesirable side reactions so as to improve the regularity of the PPy backbone.

Morphology and microstructure of polypyrrole formed by electrochemical polymerization

Using a needle–circle electrode configuration in an electrolyte solution of acetonitrile containing sodium p-toluenesulfonate and monomer, we prepared polypyrrole (PPy) with fractal pattern by electrochemical polymerization. We classify the growth patterns and draw a phase diagram on the basis of the experiments, investigating the relationship between fractal patterns and the growth conditions. A previously unrecognized morphological transition under constant voltage is reported. The microstructure of PPy is also displayed.