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Doctoral Thesis
DOI
10.11606/T.54.1992.tde-15042014-105521
Document
Author
Full name
Washington Luiz de Barros Melo
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 1992
Supervisor
Committee
Faria, Roberto Mendonça (President)
Bulhões, Luiz Otávio de Sousa
Campos, Milton Soares de
Oliveira, Sergio Mascarenhas
Vargas, Helion
Title in Portuguese
Contribuições as técnicas de espectroscopias fototérmicas e aplicações a materiais poliméricos
Keywords in Portuguese
Espectroscopia fotopiroelétrica
Espectroscopias fototérmicas
Polímeros semicondutores
Abstract in Portuguese
A espectroscopia foto-térmica tem sido largamente usada na investigação de propriedades térmicas e ópticas de materiais sólidos. Neste trabalho, desenvolvemos novas câmaras foto-térmicas as quais foram adaptadas para os estudos de materiais poliméricos. Estendemos o modelo desenvolvido por Mandelis para a espectroscopia fotopiroelétrica (PPES), incluindo nele um termo devido à reflexão de luz na interface amostra-detetor. A aplicação da técnica PPES em filmes de Poli(3-Butiltiofeno) não dopado nos permitiu obter sua condutividade e difusividade térmicas, como também seu gap de energia. Também aplicamos a técnica fotoacústica, com um flash de laser He-Ne, ao estudo de filmes de polímeros transparentes. Finalmente, desenvolvemos um método semi-empírico o qual significa a análise do sinal foto-térmico, quando ele é, principalmente, devido à difusão térmica.
Title in English
Contributions for photothermal spectroscopic techniques and applications to polymer materials
Keywords in English
Photopyroelectric spectroscopy
Photothermal spectroscopy
Semiconducting polymers
Abstract in English
Photothermal spectroscopies have been largely used in the investigation of thermal and optical properties of solids materials. In this work we developed new photothermal cells which were adapted for the study of polymerics materials. We also extended the model developed by Mandelis for the Photopyroeletric Spectroscopy (PPES), including in it a term due to the reflected light in the sample-detector interface. The application of the PPES technique in films of undopedpoly(3-butylthiophene) allowed us to obtain its thermal conductivity and diffusivity, as well as its gap energy. We also applied the photoacoustic technique, with a flash of He-Ne laser to study of transparent films of polymers. Finally we developed a semi-empiric method which simplifies the analysis of the photothermal signal, when it is mainly due to the thermal diffusion.
 
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Publishing Date
2014-04-16
 
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