S. Miyauchi

An interfering factor in the glucose sensing system with polypyrrole / glucose oxidase membrane

Abstract Glucose oxidase (GOD) was immobilized in polypyrrole (PPy) membrane during the process of the electrochemical polymerization of pyrrole for the purpose of preparing a glucose sensor. A detection of glucose was carried out amperometrically by applying a constant potential to the PPy GOD membrane. It was found that the electrolysis of hydrogen peroxide stemming from the enzyme reaction influenced the electric conductivity of the membrane.

Junction field-effect transistor using polythiophene as an active component

Abstract A junction field-effect transistor(J-FET) was fabricated on n-silicon using polythiophene as an active component. The characteristics of the transistor were studied with positive gate voltage. The largest source current flew at the gate voltage, U V and was decreased with increasing gate voltage. Then, the source current levelled off with increasing drain voltage.

Study of switching characteristic with positive temperature coefficient of poly(3-hexylthiophene)

Abstract Poly(3-hexylthiophene) (P3HTT) was prepared by chemical oxidative polymerization using FeCl3 at a relatively low temperature and dedoped with NH3 solution. A good switching characteristic with positive temperature coefficient (PTC) in the P3HT cast film was observed at the melting point. The regularity and crystallinity, as well as the relationship between the PTC switching characteristic and conformational changes of P3HT, are discussed.

Preparation of polypyrrole covalently attached with glucose oxidase and its application to glucose sensing

Abstract Glucose oxidase (GOD) was covalently attached to polypyrrole having carboxyl groups (PPy-CGOH), and polypyrrole attached with GOD(PPy-GOD) was applied to glucose sensing. The PPy-COOH was prepared by oxidative polymerization of 1-(2-cyanoethyl) pyrrole followed by hydrolysis of the cyano groups to convert them into carboxyl groups. GOD was bound to the PPy-COOH by condensation reaction between carboxyl groups of the PPy-COOH and amino groups of GOD by use of a carbodiimide reagent. The electrode made of the PPy-GOD thus obtained being used, amperometric response to glucose was monitored. The result shows that the PPy-GOD is a promising material for glucose sensor.

Positive temperature coefficient characteristics of poly(3-alkylthiophene)s

Abstract Poly(3-alkylthiophene)(P3AT) films were prepared by both electrochemical and chemically oxidative polymerization methods, and their positive temperature coefficient(PTC) characteristics were investigated in the range from 0 to 200°C. The change in the amount of tetrafluoroborate ion(BF 4 −) or iron(III) perchlorate(FeCl 3 ) which were doped into P3AT film was also estimated by infrared(IR) and ultraviolet(UV) spectrophotometry. It was found that the P3AT films chemically polymerized at a low temperature had PTC characteristics, which was not affected by the dedoping involved in thermal treatment

Electrochemical polymerization of poly(para-phenylene) and its electrical properties

Abstract Poly(para-phenylene) (PPP) film was obtained by the electrochemical polymerization of benzene in nitromethane. The as-grown films were p-type semiconductor. The structures and the properties were found to depend significantly on the polymeriztion potential and a supporting electrolyte. The electrical conductivities of the films were measured both in a plane direction and in a vertical direction. In a plane direction, DC conductivities increased with polymerization potential, whereas in a vertical direction, it decreased slightly.

Glucose-sensing characteristics of conducting polymer bound with glucose oxidase

Abstract Glucose-sensing characteristics of poly [1-(2-carboxyethyl)pyrrole] film bound with glucose oxidase (PPy-GOD) were studied in relation to the enzyme activity. The pH and temperature profiles of amperometric response of the PPy-GOD film to glucose were found to correspond to those of the activity of the glucose oxidase immobilized on pol y [1-(2-carboxyethyl)pyrrole] film.

Electrochemical synthesis of poly(para-phenylene) and its electrical properties

Summary form only given. Poly(p-phenylene) (PPP) films were obtained by the electrochemical polymerization of benzene in nitromethane. The as-grown films were p-type. Structures and properties of the films were found to depend signifficantly on the polymerization potential and the supporting electrolyte. Electrical conductivities of the films were measured in both plane and vertical directions. With an increase in the polymerization potential, the DC conductivities in a plane direction increased, whereas those in a vertical direction decreased. The AC conductivities were also measured in the range from 0.1 to 1000 KHz. The AC conductivities showed the anisotropy as well as the DC conductivities. It was possible to obtain n-type films by cation-doping. The band structures of the PPP films were calculated from the optical properties and the cyclic voltammograms.

Electronic properties of poly(3-hexylthiophene)/ N-type silicon heterojunctions

Summary form only given. Heterojunction devices consisting of poly(3-hexylthiophene) (P3HT) and n-Si were fabricated by casting the polymer on a Si substrate. In this paper, the electronic properties of the slightly doped P3HT / n-Si junctions are discussed. The fabricated devices showed the rectifying characteristics (the rectifying ratio: more than 1000). The band structures of P3HT, which were determined from the cyclic voltammograms and the absorption spectra, can explain the rectifications. The plots of log I versus forward voltage gave a straight line, but the slope was independent of temperature. Apparently, the I-V characteristics are controlled by the mechanism of multistep tunneling recombination.