Levent Toppare

Benzotriazole containing conjugated polymers for multipurpose organic electronic applications

Benzotriazole (BTz) containing polymers have recently emerged in organic electronic applications and they are increasingly attracting a great deal of attention. These polymers are reviewed from a general perspective in terms of their potential use in three main fields, electrochromics (ECs), organic solar cells (OSCs) and organic light emitting diodes (OLEDs). In order to have a better insight into the properties of these polymers, they were compared with similar polymers. Good solubility, optical and electronic properties and synthetic availability make them multipurpose materials. They combine many desired properties in polymers and their use in different device applications is examined in detail.

Graft copolymers and composites of poly(methyl methacrylate) and polypyrrole Part II

Abstract Pyrrole (2) was grafted onto a poly(methyl methacrylate) backbone which already contained the pyrrole moiety within via oxidative polymerization with FeCl 3 in nitromethane. The maximum conductivity of films cast from the reaction mixture was about 10 −2 S/cm. The conductivity and the morphology of the graft copolymers 3 depended on several effects which were studied in detail using FT-IR, thermogravimetric analysis, light and scanning electron microscopy.

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.

Conducting polymers of aniline. II: A composite as a gas sensor

Abstract The gas sensing ability of electrochemically prepared pure polyaniline and polyaniline-poly(bisphenol-A carbonate) films is investigated. The responses of the composite films to several vapours are more well defined and reproducible compared to the pure conducting polymer. The changes in resistance as determined via the two-probe technique are well defined down to a level of 0.025% vol./vol. ammonia. The possible reason for such a difference is discussed. The structure of the composite is examined through pyrolysis FT-IR studies.

Block copolymers of thiophene-capped Poly(methyl methacrylate) with pyrrole

Poly(methyl methacrylate) with a thiophene end group having narrow polydispersity was prepared by the Atom Transfer Radical Polymerization (ATRP) technique. Subsequently, electrically conducting block copolymers of thiophene-capped poly(methyl methacrylate) with pyrrole were synthesized by using p-toluene sulfonic acid and sodium dodecyl sulfate as the supporting electrolytes via constant potential electrolysis. Characterization of the block copolymers were performed by CV, FTIR, SEM, TGA, and DSC analyses. Electrical conductivities were evaluated by the four-probe technique.

A neutral state green polymer with a superior transmissive light blue oxidized state.

This report highlights the synthesis of only the second green polymer in the literature, which possesses superior properties over the first: a highly transmissive light blue color in the oxidized state with high optical contrast and excellent switching properties.

Polycarbonate-polypyrrole mixed matrix gas separation membranes

Abstract The gas separation properties of the polycarbonate–polypyrrole mixed matrix membranes were evaluated based on the introduction of conducting polymer as powder fillers. The electrically conductive fillers are obtained from two main synthesis routes namely electrochemical and chemical methods. The permeation properties of polycarbonate–polypyrrole systems are highly dependent on the synthesis method (electrochemical or chemical) and also the membrane casting conditions (casting solvent type). The introduction of electrochemically synthesized polypyrrole fillers distorted the polycarbonate matrix by forming cavities which resulted in higher permeation rates of electrochemically synthesized polypyrrole–polycarbonate (ECPPY–PC) membranes compared to both pure polycarbonate (PC) and the chemically synthesized polypyrrole–polycarbonate (CPPY–PC) films accompanied with a loss in selectivities. On the other hand, the densified structure of CPPY–PC membranes resulted in an improvement of the selectivities of industrially important gas pairs (H2/N2, O2/N2 and H2/CH4).

Immobilization of polyphenol oxidase in conducting copolymers and determination of phenolic compounds in wines with enzyme electrodes

Polyphenol oxidase (PPO) was immobilized in copolymers of thiophene functionalized menthyl monomer (MM) with pyrrole. Immobilization of enzyme was performed via entrapment in conducting copolymers during electrochemical polymerization of pyrrole. Maximum reaction rates, Michaelis-Menten constants and temperature, pH and operational stabilities of enzyme electrodes were investigated. Total amount of phenolic compounds in red wines of Turkey were analyzed by using these electrodes.

Immobilization of invertase in functionalized copolymer matrices

Abstract In this study, immobilization of invertase on functionalized polymer electrodes constructed with pyrrole-capped polyazotetrahydrofuran and polytetrahydrofuran-block-polystyrene copolymer matrices was performed. Immobilization in these enzyme electrodes was carried out by the entrapment of the enzyme in conducting polymer matrices during electrochemical polymerization of pyrrole. Sodium dodecyl sulphate was used as the supporting electrolyte in the preparation of enzyme electrodes. The effects of temperature and pH on the activity of the enzyme electrodes were examined, and re-use number studies were performed. The changes in the maximum reaction rate and the variations of the Michaelis–Menten constant were investigated.

Immobilization of invertase in conducting polypyrrole/polytetrahydrofuran graft polymer matrices

Abstract Four different polypyrrole/polytetrahydrofuran/invertase electrodes were constructed by the entrapment of invertase in conducting polymer matrices via electropolymerization. Immobilization of the enzyme was achieved by the application of a 1.1 V constant potential to a platinum electrode for 30 min in a solution containing 0.01 M pyrrole, 0.4 mg/ml invertase and 0.4 mg/ml sodium dodecyl sulphate. Performance of each electrode was optimized by examining the effects of pH and temperature on the properties of the electrodes. The changes in the maximum velocity of the reaction and variation of Michaelis–Menten constant upon immobilization were investigated. The enzyme immobilized in those matrices retained its activity for several months.