Correlação da concentração limite de nanotubos de carbono com as propriedades químicas e físicas de solventes por meio da técnica de centrifugação e análise espectrofotométrica
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Data
2023-06-28
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Universidade Estadual Paulista (Unesp)
Resumo
Neste estudo, abordamos a dificuldade atual de obter altas concentrações de nanopartículas de carbono em meio líquido. O objetivo principal foi desenvolver uma metodologia para avaliar e prever a concentração limite de um nanomaterial em meio líquido. Utilizamos o nanomaterial MWCNT (Multi-Walled Carbon Nanotube) fornecido pelo Laboratório de Síntese de Nanomateriais do Departamento de Física da UFMG. As concentrações limites foram obtidas através da centrifugação de dispersões hiperconcentradas de MWCNT em 26 solventes. A análise de concentração das amostras foi realizada utilizando um espectrofotômetro OceanOptics USB2000+. Durante o estudo, foram feitas adaptações e discutidos os aspectos de sensibilidade, resolução, exatidão e precisão do equipamento. Os resultados demonstraram a confiabilidade e precisão do aparato experimental utilizado, produzindo resultados reprodutíveis. Em relação aos resultados, foram estabelecidas correlações entre os Parâmetros de Solubilidade de Hansen (PSH) e a dispersão dos nanomateriais, porém observou-se que os PSH não são suficientes para explicar completamente esse fenômeno. Outros parâmetros, como viscosidade, densidade e tensão superficial dos solventes, também foram explorados, mas não foi possível estabelecer uma correlação clara entre esses parâmetros e a capacidade dos solventes em dispersar os MWCNT. No geral, este estudo contribui para avançar na compreensão e predição da concentração limite de nanomateriais em meio líquido, destacando a importância de considerar não apenas os PSH, mas também outros parâmetros intrínsecos dos solventes na dispersão eficaz dos nanomateriais.
In this study, we address the current difficulty of achieving high concentrations of carbon nanoparticles in liquid media. The main objective was to develop a methodology to evaluate and predict the limiting concentration of a nanomaterial in liquid media. We used the MWCNT (Multi-Walled Carbon Nanotube) provided by the Nanomaterial Synthesis Laboratory at the Department of Physics, UFMG. The limiting concentrations were obtained by centrifuging hyperconcentrated dispersions of MWCNT in 26 solvents. The concentration analysis of the samples was performed using an OceanOptics USB2000+ spectrophotometer. During the study, adaptations were made and the sensitivity, resolution, accuracy, and precision aspects of the equipment were discussed. The results demonstrated the reliability and precision of the experimental setup, providing reproducible results. Regarding the results, correlations were established between the Hansen Solubility Parameters (HSP) and the dispersion of nanomaterials, but it was observed that the HSP alone are not sufficient to fully explain this phenomenon. Other parameters, such as viscosity, density, and surface tension of the solvents, were also explored, but it was not possible to establish a clear correlation between these parameters and the dispersibility of MWCNT in the solvents. Overall, this study contributes to advancing the understanding and prediction of the limiting concentration of nanomaterials in liquid media, highlighting the importance of considering not only the HSP but also other intrinsic parameters of the solvents for effective dispersion of nanomaterials.
In this study, we address the current difficulty of achieving high concentrations of carbon nanoparticles in liquid media. The main objective was to develop a methodology to evaluate and predict the limiting concentration of a nanomaterial in liquid media. We used the MWCNT (Multi-Walled Carbon Nanotube) provided by the Nanomaterial Synthesis Laboratory at the Department of Physics, UFMG. The limiting concentrations were obtained by centrifuging hyperconcentrated dispersions of MWCNT in 26 solvents. The concentration analysis of the samples was performed using an OceanOptics USB2000+ spectrophotometer. During the study, adaptations were made and the sensitivity, resolution, accuracy, and precision aspects of the equipment were discussed. The results demonstrated the reliability and precision of the experimental setup, providing reproducible results. Regarding the results, correlations were established between the Hansen Solubility Parameters (HSP) and the dispersion of nanomaterials, but it was observed that the HSP alone are not sufficient to fully explain this phenomenon. Other parameters, such as viscosity, density, and surface tension of the solvents, were also explored, but it was not possible to establish a clear correlation between these parameters and the dispersibility of MWCNT in the solvents. Overall, this study contributes to advancing the understanding and prediction of the limiting concentration of nanomaterials in liquid media, highlighting the importance of considering not only the HSP but also other intrinsic parameters of the solvents for effective dispersion of nanomaterials.
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Palavras-chave
Dispersão, Espectrofotometria, Nanotubo de carbono, Parâmetros de solubilidade de Hansen, Dispersion, Spectrophotometry, Carbon nanotube