Immobilization of invertase in conducting polymer matrices

Cataloged from PDF version of article.This paper reports a novel approach in the electrode immobilization of an enzyme, invertase, by electrochemical polymerization of pyrrole in the presence of enzyme. The polypyrrolelinvertase and polyamide/polypyrrole/invertase electrodes were constructed by the entrapment of enzyme in conducting matrices during electrochemical polymerization of pyrrole. This study involves the preparation and characterization of polypyrrole/invertase and polyamidelpolypyrrolelinvertase electrodes under conditions compatible with the enzyme. It demonstrates the effects of pH and temperature on the properties of enzyme electrode. Enzyme leakage tests were carried out during reuse number studies. The preparation of enzyme electrodes was done in two different electrolyte/ solvent systems. The enzyme serves as a sucrose electrode and retains its activity for several months. (c) 1997 Elsevier Science Limited. All rights reserve

A CONDUCTING COMPOSITE OF POLYPYRROLE .1. SYNTHESIS AND CHARACTERIZATION

A conducting composite of polypyrrole was prepared via electrochemical methods. A polyamide was used as the insulating matrix polymer. The characterization of the composite was done by FT-IR, SEM, TGA, DSC and pyrolysis studies. Conductivity and solubility studies together with spectroscopic methods reveal that H bonding exists between the two polymers and a possible grafting to a certain extent

Conducting polymer composites of polypyrrole and a poly(arylene ether ketone)

Electrically conducting composites of polypyrrole and a poly(arylene ether ketone) were synthesized by electroinitiated polymerization of pyrrole on a poly(arylene ether ketone)-coated platinum electrode. The electrolysis medium was water and p-toluene sulfonic acid. The conductivities of the composites were in the range 1-10 S/cm. The composites were characterized by scanning electron microscopy, Fourier transform infrared, and thermal analyses. The composites were found to be composed of bilayers which can be peeled into two free-standing polymer films. The solution side of the polypyrrole layer of the alloy film contains globular structures, whereas the other side is smoother

Conducting polymer composites of polypyrrole and polyimide

Polymeric composites with conductivities ranging from 1 to 10 S/cm were prepared by electrochemically polymerizing pyrrole in a matrix of polyimide. The polyimide/polypyrrole (PI/PPy) composites were characterized by SEM, TGA, FT-IR and electrical conductivity measurements. The cyclic voltammetry technique was used to determine the electroactivity and the electrochemical properties of PPy and PI/PPy. Copyright © 1996 by Marcel Dekker, Inc

A conducting composite of polypyrrole II. As a gas sensor

Pure polypyrrole (PPy) and polypyrrole-polyamide (PPy-PA) composite films were synthesized electrochemically. The gas-sensing ability was investigated for both pure PPy and PPy-PA films. The composite films' response to several gases are better defined and reproducible compared to pristine conducting polymer. Electrochemical behaviour of PPy and PPy-PA electrodes in the presence of pyrrole and pyrrole-free medium is investigated via cyclic voltammetry. Mass spectrometry studies strictly reveal that the composite is completely different to a mechanical mixture. This phenomenon is discussed in comparison to polyaniline-polycarbonate composite. © 1995

Synthesis of a novel poly(arylene ether ketone) and its conducting composites with polypyrrole

The synthesis of a 1,3-bis(4-fluorobenzoyl)-5-tert-butyl benzene and hexafluoro bisphenol A based poly(arylene ether ketone) (PEK) was described. The electrically conductive composites of polypyrrole (PPy) and PEK were formed by electropolymerization of pyrrole on a PEK coated platinum electrode in a medium containing water andp-toluenesulfonic acid as the solvent and the electrolyte, respectively. The electrical conductivity of the composites was found to be between 1 and 4 S/cm. The polypyrrole/poly (ether ketone) composites were characterized by scanning electron microscopy, FT-IR and thermal analyses (TGA, DSC). © 1997 Elsevier Science S.A

Synthesis of a hexafluoropropylidene-bis(phthalic anhydride)-based polyimide and its conducting polymer composites with polypyrrole

A new electrically conducting composite film from polypyrrole and 4,4′(hexafluoroisopropylidene)-bis(phthalic anhydride)-based polyimide was prepared. Pyrrole and the dopant ion can easily penetrate through the polyimide substrate and electropolymerize on the platinum (Pt) electrode due to the swelling of the polyimide on the metal electrode. The electrochemical properties of polypyrrole-polyimide (PPy/PI ) composite films have been investigated by using cyclic voltammetry. The PPy/PI composite film is suitable for use as the electroactive material owing to its stable and controllable electrochemical properties. The electrical conductivity of composites falls in the range 0.0035-15 S/cm. Scanning electron micrograph, FTIR, and thermal studies indicate that PPy and PI form a homogeneous material rather than a simple mixture. © 1997 John Wiley & Sons, Inc

Revisiting UF6, NpF6 and PuF6 for bonding and molecular surface analysis within density functional theory: Comparative study at the different theory levels with the same basis set

UF6, NpF6 and PuF6 have been reexamined for their bonding characteristics and molecular surfaces. The bonding properties of these compounds were analyzed by calculating bond orders, partial charges, dipole moments, localized molecular orbitals, and topological properties. The bond orders increase with the atomic number (Z) of actinide as the bond lengths decrease. The partial charges, calculated by Atoms in Molecules (AIM) and Mulliken methods, and the bond dipole moment decrease with increasing Z. There is a fluctuation in the partial charge value for Np according to other charge models. The f character of the localized molecular orbital increases with Z. In general, the parameters obtained from topological analysis show an increase in the covalency across the period for U, Np and Pu. The molecular volume and surface obtained from surface analysis decrease with Z, which is consistent with the bond lengths. The molecular surface electrostatic potentials for intermolecular interactions decrease with Z according to surface analysis. The mass density and heat of sublimation data are interpreted based on molecular surface analysis results. All the density functionals and HERDB with the same basis set give consistent results for almost all the quantities calculated

Conducting polymer composites of polypyrrole and a poly(arylene ether ketone)

Electrically conducting composites of polypyrrole and a poly(arylene ether ketone) were synthesized by electroinitiated polymerization of pyrrole on a poly(arylene ether ketone)-coated platinum electrode. The electrolysis medium was water and p-toluene sulfonic acid. The conductivities of the composites were in the range 1-10 S/cm. The composites were characterized by scanning electron microscopy, Fourier transform infrared, and thermal analyses. The composites were found to be composed of bilayers which can be peeled into two free-standing polymer films. The solution side of the polypyrrole layer of the alloy film contains globular structures, whereas the other side is smoother

Immobilization of invertase in conducting polymer matrices

This paper reports a novel approach in the electrode immobilization of an enzyme, invertase, by electrochemical polymerization of pyrrole in the presence of enzyme. The polypyrrole/invertase and polyamide/polypyrrole/invertase electrodes were constructed by the entrapment of enzyme in conducting matrices during electrochemical polymerization of pyrrole. This study involves the preparation and characterization of polypyrrole/invertase and polyamide/polypyrrole/invertase electrodes under conditions compatible with the enzyme. It demonstrates the effects of pH and temperature on the properties of enzyme electrode. Enzyme leakage tests were carried out during reuse number studies. The preparation of enzyme electrodes was done in two different electrolyte/solvent systems. The enzyme serves as a sucrose electrode and retains its activity for several months.This paper reports a novel approach in the electrode immobilization of an enzyme, invertase, by electrochemical polymerization of pyrrole in the presence of enzyme. The polypyrrole/invertase and polyamide/polypyrrole/invertase electrodes were constructed by the entrapment of enzyme in conducting matrices during electrochemical polymerization of pyrrole. This study involves the preparation and characterization of polypyrrole/invertase and polyamide/polypyrrole/invertase electrodes under conditions compatible with the enzyme. It demonstrates the effects of pH and temperature on the properties of enzyme electrode. Enzyme leakage tests were carried out during reuse number studies. The preparation of enzyme electrodes was done in two different electrolyte/solvent systems. The enzyme serves as a sucrose electrode and retains its activity for several months