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Advisor(s)
Abstract(s)
A primeira parte deste trabalho centrou-se no desenvolvimento de materiais que podem ajudar a ultrapassar as atuais limitações no armazenamento e consumo de energia. Desenvolvemos nanofluídos baseados em nanopartículas não tóxicas de carbono (NPs): carbon dots (Cdots) funcionalizados com líquidos iónicos. Aqui, quisemos mostrar que estes novos nanofluídos são, não só interessantes como possíveis eletrólitos, mas também como novos separadores híbridos orgânicos/inorgânicos. Como tal, desenvolvemos um método de imobilização utilizando o poli(álcool vinílico) (PVA). De facto, os Cdots altamente condutores foram retidos com sucesso no interior da membrana mesmo após a aplicação de vários ciclos de molhagem/secagem. Além disso, as características morfológicas não se alteraram após esses ciclos e permaneceram constantes durante mais de quatro meses. Estes nanofluídos podem ser uma abordagem interessante para resolver alguns dos problemas atuais nos campos das baterias de estado sólido e do armazenamento de energia, entre outros. Na segunda parte o nosso foco foi a necessidade de desenvolver um sensor analítico específico que conseguisse identificar e quantificar o Fe(II). O sensor fluorescente aqui descrito pode detetar com sucesso o Fe(II) e discriminar este ião de outros analitos que normalmente atuam como interferentes em meios biológicos. Além disso, este sensor à base de fluoresceinamina reduzida (RFL) tem alta fotoestabilidade e constante de dissociação, o que indica que o complexo obtido entre a fluoresceinamina reduzida e o Fe(II) é muito estável. Este sensor fluorescente tem um mecanismo de ligação de 1:1 e foi encontrada uma ligação do tipo cooperativa positiva entre o analito e o sensor. Os parâmetros de deteção, quantificação e sensibilidade do sensor são: 21,6 ± 0,1 μM; 65,6 ± 0,1 μM e 48 ± 3 (×107) μM, respetivamente.
The first part of this work focused on the development of materials that can help overcome the current limitations in energy storage and consumption. We developed nanofluids based on nontoxic, carbon nanoparticles (NPs): carbon dots (Cdots) functionalized with ionic liquids. Here, we wanted to prove that these new nanofluids are, not only interesting as possible electrolytes, but also as new organic/inorganic hybrid separators. As such, we developed an entrapment method using poly(vinyl alcohol) (PVA). Indeed, the highly conductive Cdots were successfully retained inside the membrane even upon the application of several wetting/drying cycles. Moreover, the morphological characteristics did not change upon these cycles and remained stable for more than four months. These nanofluids could be an interesting approach to tackle some of the current problems in the fields of solid-state batteries, and energy storage, among others. In the second part our focus was on the need to develop a specific analytical sensor that can identify and quantify Fe(II). The turn-on fluorescent sensor here described can successfully detect Fe(II) and discriminate this ion from other analytes that commonly act as interferents in biological media. Moreover, this reduced fluoresceinamine-based (RFL) sensor has a high photostability and high dissociation constant, which is an indication that the complex obtained between reduced fluoresceinamine and Fe(II) is highly stable. This fluorescence-based sensor has a binding mechanism of 1:1 and a positive cooperativity was found between analyte and sensor. The detection, quantification and sensitivity parameters of the sensor were determined: 21.6 ± 0.1 μM; 65.6 ± 0.1 μM and 48 ± 3 (×107 ) μM, respectively.
The first part of this work focused on the development of materials that can help overcome the current limitations in energy storage and consumption. We developed nanofluids based on nontoxic, carbon nanoparticles (NPs): carbon dots (Cdots) functionalized with ionic liquids. Here, we wanted to prove that these new nanofluids are, not only interesting as possible electrolytes, but also as new organic/inorganic hybrid separators. As such, we developed an entrapment method using poly(vinyl alcohol) (PVA). Indeed, the highly conductive Cdots were successfully retained inside the membrane even upon the application of several wetting/drying cycles. Moreover, the morphological characteristics did not change upon these cycles and remained stable for more than four months. These nanofluids could be an interesting approach to tackle some of the current problems in the fields of solid-state batteries, and energy storage, among others. In the second part our focus was on the need to develop a specific analytical sensor that can identify and quantify Fe(II). The turn-on fluorescent sensor here described can successfully detect Fe(II) and discriminate this ion from other analytes that commonly act as interferents in biological media. Moreover, this reduced fluoresceinamine-based (RFL) sensor has a high photostability and high dissociation constant, which is an indication that the complex obtained between reduced fluoresceinamine and Fe(II) is highly stable. This fluorescence-based sensor has a binding mechanism of 1:1 and a positive cooperativity was found between analyte and sensor. The detection, quantification and sensitivity parameters of the sensor were determined: 21.6 ± 0.1 μM; 65.6 ± 0.1 μM and 48 ± 3 (×107 ) μM, respectively.
Description
Keywords
Nanofluídos Carbon dots Líquidos iónicos Eletrólitos Aplicações energéticas Fluoresceinamina reduzida Específico Deteção de ferro(II) Nanofluids Carbon dots Ionic liquids Electrolytes Energy applications Reduced fluoresceinamine Specific Iron(II) detection