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Doctoral Thesis
DOI
10.11606/T.54.1982.tde-13102009-144758
Document
Author
Full name
José Alberto Giacometti
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 1982
Supervisor
Title in Portuguese
Corona com corrente constante: um novo método para o estudo de transporte de carga em isolantes. Aplicação em polímeros.
Keywords in Portuguese
Carregamento por descarga corona
Corrente constante
Filmes dielétricos
Instrumentação para dielétricos
Polímeros
Abstract in Portuguese
É apresentado neste trabalho um novo método de carga de filmes dielétricos com descarga corona, no qual a corrente de carga da amostra é mantida constante durante a deposição dos íons, enquanto o potencial de superfície é medido pela técnica do capacitor vibrante. O método foi aplicado no estudo de transporte e armazenamento de portadores em polímeros, principalmente no Teflon FEP e PVDF. No Teflon FEP carregado com corona positiva e negativa, a superfície do material exerce um papel predominante. O transporte de elétrons é dominado pelos traps de volume. Para a corona positiva a injeção é controlada pelo trapping e detrapping das armadilhas superficiais. No PVDF os resultados obtidos são razoavelmente independentes da polaridade da descarga corona. Para baixos campos elétricos o potencial de superfície parece ser determinado pela condutividade do material, perturbado pela existência de uma polarização de volume.
Title in English
A new method for the study of charged transport in electric insulators. Application on polymers.
Keywords in English
Constant current
Corona charging
Dielectric instrumentation
Dieletric films
Polymers
Abstract in English
A new method of charging dielectric films with corona current is presented here, the sample charging current being keept constant during the deposition, while the surface potential is measured by vibrating capacitor technique. The method was applied to study the carrier transport and storage in polymers, mainly in Teflon FEP and PVDF. For positive and negative corona in Teflon FEP, the surface plays an important role. The electron transport is dominated by bulk traps. For positive corona injection into the volume is controlled by surface trapping and detrapping. For PVDF the results are almost independent of the current polarity. For low electrical fields, the results indicate that the surface potential is determined by the material conductivity, perturbed by the build up of a bulk polarization.
 
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Publishing Date
2009-10-20
 
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