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Master's Dissertation
DOI
10.11606/D.54.1984.tde-14102009-093531
Document
Author
Full name
Osvaldo Novais de Oliveira Junior
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 1984
Supervisor
Title in Portuguese
Estudo do transporte de carga em amostras de teflon FEP sob descarga corona no ar e no nitrogênio.
Keywords in Portuguese
Descarga corona
Polímeros
Abstract in Portuguese
O Triodo de corona com corrente constante foi utilizado em medidas da evolução do potencial de superfície de amostras de FEP 12 e 25 μm, carregadas com corona positiva e negativa no FEP 12 e 25 μm carregadas com corona positiva e negativa no ar e no nitrogênio. Estas medidas permitem concluir que não há diferença a nível de transporte de cargas entre os resultados com os dois gases. Apenas a umidade é importante para a subida e o decaimento do potencial de superfície. A subida do potencial de superfície de amostras de FEP 12 μm carregadas com corona negativa foi interpretada por meio da justaposição de dois modelos teóricos. No material só existem armadilhas profundas, em número finito, tanto na superfície quanto no volume; sendo que as de volume estão uniformemente distribuídas. Nenhum decaimento significativo de potencial é observado. A superfície desempenha um papel predominante na captura e injeção de portadores nas amostras de 12 μm carrega - das com corona positiva. Um modelo teórico que supõe schubweg dependente do campo médio reproduz os resultados experimentais.
Title in English
Charge transport in FEP Teflon Films submsted to corona discharge in air and in nitrogen.
Keywords in English
Corona discharge
Polymer
Abstract in English
The corona triode with constant current was used to measure the evolution of surface potential of FEP 12 and 25 μm samples, charged with positive and negative corona in air and in nitrogen. No difference in the transport properties in thin samples was observed when the gas was changed and this allowed us to conclude that electrons and holes are the carriers responsible by the transport of charge in the material. Only the moisture is important to the build up and decay of surface potential. The build up of surface potential of 12 μm samples charged with negative corona was interpreted by means of a deep fast trapping model in the beginning, followed by an increase of the trapping time when saturation is approached. Surface traps are also present. No significative potential decay is observed. The surface performs an important role in the trap¬ ping and injection of carriers into the bulk of 12 μm samples charged with positive corona. A theoretical model that assumes schubweg dependent on mean electric field fits the experimental results.
 
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Publishing Date
2009-10-23
 
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