Desenvolvimento de dosímetros de radiação ionizante baseados em soluções poliméricas e materiais de baixo custo
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Data
2020-02-27
Autores
Colturato, Simone Ramos Alvarenga
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Universidade Estadual Paulista (Unesp)
Resumo
Radiações ionizantes são atualmente empregadas em diversos setores, inclusive na área da saúde. Contudo, devido às suas características potencialmente danosas à saúde humana, faz-se necessário um monitoramento adequado e contínuo, especialmente no que tange a dosimetria pessoal. Neste contexto, materiais conjugados em solução têm sido apontados como sistemas promissores para a confecção de dosímetros. Apesar das interessantes propriedades destes sistemas, a maioria deles apresenta baixa sensibilidade, o que restringe a sua aplicação efetiva em situações reais. O presente trabalho visa o desenvolvimento de dosímetros baseados em soluções poliméricas e materiais orgânicos de baixo custo relativo. Neste estudo trabalhou-se com dois sistemas principais: i) baseado no polímero poli [(9,9- dioctilfluorenil-2,7,diil)-co-(1,4-vinilienofenileno)] (F8PV) em solução de clorofórmio; e ii) no corante Índigo-carmin (IC) diluído em água, com e sem a presença de nanopartículas de óxido de zinco ou sal inorgânico (NaCl). Amostras com diferentes concentrações foram consideradas e diferentes doses de radiação X foram empregadas. A resposta dosimétrica foi avaliada por meio da análise do espectro de absorção óptica dos sistemas na região do ultravioleta-visível e espectro de infravermelho (FTIR). Os resultados obtidos apontam o sistema F8PV/CHCl3 como um sistema dosimétrico promissor com respostas otimizadas em relação à sistemas poliméricos similares, permitindo a aferição de doses inferiores a 5 Gy. Os resultados foram interpretados considerando possíveis interações entre radicais gerados da dissociação do solvente com as cadeias poliméricas. Respostas pouco significativas foram obtidas para sistemas baseados em Índigo-carmim o que reforça o papel essencial de halogênios nas propriedades dosimétricas de sistemas conjugados em solução.
Ionizing radiation is currently employed in a variety of areas, including in healthcare. However, due to its potentially harmful characteristics to human health, an adequate and continuous monitoring is necessary, especially regarding personal dosimetry. In this context, conjugated materials in solution have been pointed out as promising systems for the design of dosimeters. Despite the interesting properties of these systems, most of them have low sensitivity, which restricts their effective application in real situations. The present work aims the development of dosimetric systems based on solutions containing conjugated materials. Two systems were evaluated: i) based on poly [(9,9- dioctylfluorenyl-2,7,diyl)-co-(1,4-vinylienephenylene)] polymer in chloroform solution; and ii) aqueous solutions of Indigo-carmine dye, with and without zinc oxide nanoparticles or inorganic salt (NaCl). Samples with different concentrations were considered and different X-ray doses were employed. The dosimetric responses were evaluated by analyzing the optical absorption spectrum of the systems in the ultravioletvisible range and the vibrational spectrum. The results point out the F8PV/CHCl3 system as a promising dosimeter with optimized responses in relation to other similar polymeric systems, allowing the measurement of doses lower than 5 Gy. The results were interpreted considering the interaction between free radicals generated from solvent dissociation with the polymeric chains. Non-significant responses were obtained for Indigo-carmine based systems which reinforces the essential role of halogens in the dosimetric properties of conjugated materials in solutions.
Ionizing radiation is currently employed in a variety of areas, including in healthcare. However, due to its potentially harmful characteristics to human health, an adequate and continuous monitoring is necessary, especially regarding personal dosimetry. In this context, conjugated materials in solution have been pointed out as promising systems for the design of dosimeters. Despite the interesting properties of these systems, most of them have low sensitivity, which restricts their effective application in real situations. The present work aims the development of dosimetric systems based on solutions containing conjugated materials. Two systems were evaluated: i) based on poly [(9,9- dioctylfluorenyl-2,7,diyl)-co-(1,4-vinylienephenylene)] polymer in chloroform solution; and ii) aqueous solutions of Indigo-carmine dye, with and without zinc oxide nanoparticles or inorganic salt (NaCl). Samples with different concentrations were considered and different X-ray doses were employed. The dosimetric responses were evaluated by analyzing the optical absorption spectrum of the systems in the ultravioletvisible range and the vibrational spectrum. The results point out the F8PV/CHCl3 system as a promising dosimeter with optimized responses in relation to other similar polymeric systems, allowing the measurement of doses lower than 5 Gy. The results were interpreted considering the interaction between free radicals generated from solvent dissociation with the polymeric chains. Non-significant responses were obtained for Indigo-carmine based systems which reinforces the essential role of halogens in the dosimetric properties of conjugated materials in solutions.
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polímero, propriedades óticas, radiação ionizante, dosimetria, polymer, optical properties, radiation, dosimetry