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Titolo:
STUDY OF CONDUCTING POLYPYRROLE FILMS IN THE MICROWAVE REGION
Autore:
KAYNAK A; UNSWORTH J; BEARD GE; CLOUT R;
Indirizzi:
UNIV TECHNOL SYDNEY,SCH PHYS SCI,CTR MAT TECHNOL,POB 123 BROADWAY NSW2007 AUSTRALIA UNIV TECHNOL SYDNEY,SCH ELECT ENGN BROADWAY NSW 2007 AUSTRALIA
Titolo Testata:
Materials research bulletin
fascicolo: 11, volume: 28, anno: 1993,
pagine: 1109 - 1125
SICI:
0025-5408(1993)28:11<1109:SOCPFI>2.0.ZU;2-J
Fonte:
ISI
Lingua:
ENG
Keywords:
CONDUCTING POLYMERS; DIELECTRICS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
17
Recensione:
Indirizzi per estratti:
Citazione:
A. Kaynak et al., "STUDY OF CONDUCTING POLYPYRROLE FILMS IN THE MICROWAVE REGION", Materials research bulletin, 28(11), 1993, pp. 1109-1125

Abstract

Dielectric properties of the electrochemically synthesised polymer polypyrrole with a wide range of doping levels are presented. Methods for determining the complex dielectric constant in the microwave regime are discussed. The variation of the complex dielectric constant as a function of polymer dopant concentration at room temperature using cylindrical and rectangular cavity perturbation methods at frequencies of 2.45 GHz and 10 GHz is presented. Measurements indicate that the real and imaginary parts of the dielectric constant increase in magnitude with increasing polymer doping level. Complex dielectric constant measurements were continued on semiconducting polypyrrole films with a dc conductivity range of 1x10(-3)-5x10(-2) S/cm for the temperature range 90K-300K. The real part epsilon' of the complex dielectric constant increased slightly with increase of temperature whereas the imaginary part epsilon'' increased significantly with temperature. The rate of change of the dielectric loss increased with temperature and the magnitude of the loss at a given temperature increased with increasing polymerdoping levels. Reflection, transmission and absorption behaviour of polypyrrole films with dc conductivities ranging from 0.001 S/cm to 50 S/cm are also presented. Results indicate that conductivity of the doped polypyrrole films have a significant effect on transmission, reflection and absorption of microwaves. Samples with low conductivity (low dopant concentration) exhibited high transmission whereas highly conducting films were reflective. Significant absorption of microwave radiation was only observed for samples of intermediate conductivity. Solutions by theoretical methods were in good agreement with the experimentally measured results from the polypyrrole films and hence confirm thedependability of the dielectric measurement method used.

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Documento generato il 02/07/20 alle ore 22:05:45