Structure-property correlations of synthetic eumelanin towards bioelectronic applications
Ano de defesa: | 2021 |
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Autor(a) principal: | |
Orientador(a): | |
Banca de defesa: | |
Tipo de documento: | Tese |
Tipo de acesso: | Acesso aberto |
Idioma: | eng |
Instituição de defesa: |
Universidade Estadual Paulista (Unesp)
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Programa de Pós-Graduação: |
Não Informado pela instituição
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Departamento: |
Não Informado pela instituição
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País: |
Não Informado pela instituição
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Palavras-chave em Português: | |
Link de acesso: | http://hdl.handle.net/11449/204105 |
Resumo: | The natural pigment known as melanin has become a very promising material for many technological applications, but especially in the emerging area of organic bioelectronics due to its charge transport properties and biocompatibility. Thus, this thesis aimed to shed light on the optoelectronic properties of a series of melanin derivatives and apply such materials in organic devices. With this in mind, synthetic melanin derivatives were investigated using structural, optical, magnetic resonance and electrical techniques to elucidate the basic behavior of the materials as well as their charge transport properties. These set of characterizations included depth-profile X-ray photoelectron spectroscopy, photoluminescence, UV-Vis-NIR and ellipsometry spectroscopy, electron paramagnetic resonance, DC conductivity and electrochemical impedance spectroscopy under hydration control and neutron scattering. It was possible to show that soluble melanin synthesized in water behaves similarly to standard (and insoluble) melanin with slight variations that could be related small changes in the oxidation state of the samples or to different film thickness. On the other hand, the sulfonated melanin behaves like the standard one, indicating that these materials can be considered part of the “melanin family” of compounds. However, there were at least two key differences; it appears to have a lower ionic conductivity, most likely due to sulfonated groups replacing available conductive protons. However, this is compensated by the fact that sulfonated melanins exhibit easier thin-film formation on different surfaces, making it more attractive for device applications. We further demonstrated that SMel (one of the sulfonated melanin derivatives) is sensitive to pH in a carbon/graphene screen-printed electrode, that is, a sensor. This device can be considered a proof of concept that sulfonated melanin can act as transduction material for bioelectronics applications. |
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Structure-property correlations of synthetic eumelanin towards bioelectronic applicationsCorrelação propriedade-estrutura de eumelaninas sintéticas para aplicações bioeletrônicasBioelectronic materialMelaninSynthetic melaninOptoelectronicsCharge transportpH sensorMaterial bioeletrônicoMelaninaMelanina sintéticaOptoeletrônicaTransporte de cargaSensor de pHThe natural pigment known as melanin has become a very promising material for many technological applications, but especially in the emerging area of organic bioelectronics due to its charge transport properties and biocompatibility. Thus, this thesis aimed to shed light on the optoelectronic properties of a series of melanin derivatives and apply such materials in organic devices. With this in mind, synthetic melanin derivatives were investigated using structural, optical, magnetic resonance and electrical techniques to elucidate the basic behavior of the materials as well as their charge transport properties. These set of characterizations included depth-profile X-ray photoelectron spectroscopy, photoluminescence, UV-Vis-NIR and ellipsometry spectroscopy, electron paramagnetic resonance, DC conductivity and electrochemical impedance spectroscopy under hydration control and neutron scattering. It was possible to show that soluble melanin synthesized in water behaves similarly to standard (and insoluble) melanin with slight variations that could be related small changes in the oxidation state of the samples or to different film thickness. On the other hand, the sulfonated melanin behaves like the standard one, indicating that these materials can be considered part of the “melanin family” of compounds. However, there were at least two key differences; it appears to have a lower ionic conductivity, most likely due to sulfonated groups replacing available conductive protons. However, this is compensated by the fact that sulfonated melanins exhibit easier thin-film formation on different surfaces, making it more attractive for device applications. We further demonstrated that SMel (one of the sulfonated melanin derivatives) is sensitive to pH in a carbon/graphene screen-printed electrode, that is, a sensor. This device can be considered a proof of concept that sulfonated melanin can act as transduction material for bioelectronics applications.O pigmento natural conhecido como melanina tem se tornado um material bastante promissor para muitas aplicações tecnológicas, mas principalmente na área emergente da bioeletrônica orgânica devido as suas propriedades de transporte de cargas e biocompatibilidade. Desta forma, esta tese tem como objetivo estudar as propriedades optoeletrônicas de uma série de derivados de melanina e aplicar estes materiais em dispositivos orgânicos. Com isto em mente, derivados sintéticos de melanina foram investigados utilizando técnicas estruturais, ópticas, de ressonância magnética e elétricas para elucidar suas propriedades, em especial as de transporte de carga. Este conjunto de caracterizações inclui técnicas como a espectroscopia de fotoelétrons de raios-X com perfil de profundidade, UV-Vis-NIR, fotoluminescência e elipsometria, ressonância paramagnética eletrônica, condutividade elétrica DC e espectroscopia de impedância eletrônica com controle de hidratação e espalhamento de nêutrons. Mostramos que as melaninas solúveis sintetizadas em água se comportam de maneira similar a amostra padrão (e insolúvel) com pequenas variações que podem estar relacionadas a pequenas diferenças no estado de oxidação das amostras ou a diferentes espessuras dos filmes. Por outro lado, as melaninas sulfonadas se comportam como a amostra padrão, indicando que estes materiais podem ser considerados como parte de compostos da “família melanina”. Contudo, existem pelo menos duas importantes diferenças: ela aparenta ter uma menor condutividade iônica, provavelmente devido aos grupos sulfonados substituindo os prótons condutores disponíveis. Entretanto, isto é compensado pelo fato de que a melanina sulfonada apresenta maior facilidade de formação de filmes finos em diferentes superfícies o que a torna mais atrativa para aplicação em dispositivos. Demonstramos ainda que a SMel (um dos derivados de melanina sulfonados) é um material sensível ao pH em um eletrodo impresso de carbono/grafeno, ou seja, em um sensor. Este dispositivo pode ser considerado a prova de conceito de que as amostras sulfonadas podem atuar como um material para transdução para aplicações bioeletrônicas.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP: 2015/23000-1FAPESP: 2018/02411-1Universidade Estadual Paulista (Unesp)Graeff, Carlos Frederico de Oliveira [UNESP]Universidade Estadual Paulista (Unesp)Paulin, João Vitor2021-03-16T20:06:43Z2021-03-16T20:06:43Z2021-02-26info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisapplication/pdfhttp://hdl.handle.net/11449/20410533004056083P7enginfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESP2023-11-03T06:06:22Zoai:repositorio.unesp.br:11449/204105Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestopendoar:29462023-11-03T06:06:22Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false |
dc.title.none.fl_str_mv |
Structure-property correlations of synthetic eumelanin towards bioelectronic applications Correlação propriedade-estrutura de eumelaninas sintéticas para aplicações bioeletrônicas |
title |
Structure-property correlations of synthetic eumelanin towards bioelectronic applications |
spellingShingle |
Structure-property correlations of synthetic eumelanin towards bioelectronic applications Paulin, João Vitor Bioelectronic material Melanin Synthetic melanin Optoelectronics Charge transport pH sensor Material bioeletrônico Melanina Melanina sintética Optoeletrônica Transporte de carga Sensor de pH |
title_short |
Structure-property correlations of synthetic eumelanin towards bioelectronic applications |
title_full |
Structure-property correlations of synthetic eumelanin towards bioelectronic applications |
title_fullStr |
Structure-property correlations of synthetic eumelanin towards bioelectronic applications |
title_full_unstemmed |
Structure-property correlations of synthetic eumelanin towards bioelectronic applications |
title_sort |
Structure-property correlations of synthetic eumelanin towards bioelectronic applications |
author |
Paulin, João Vitor |
author_facet |
Paulin, João Vitor |
author_role |
author |
dc.contributor.none.fl_str_mv |
Graeff, Carlos Frederico de Oliveira [UNESP] Universidade Estadual Paulista (Unesp) |
dc.contributor.author.fl_str_mv |
Paulin, João Vitor |
dc.subject.por.fl_str_mv |
Bioelectronic material Melanin Synthetic melanin Optoelectronics Charge transport pH sensor Material bioeletrônico Melanina Melanina sintética Optoeletrônica Transporte de carga Sensor de pH |
topic |
Bioelectronic material Melanin Synthetic melanin Optoelectronics Charge transport pH sensor Material bioeletrônico Melanina Melanina sintética Optoeletrônica Transporte de carga Sensor de pH |
description |
The natural pigment known as melanin has become a very promising material for many technological applications, but especially in the emerging area of organic bioelectronics due to its charge transport properties and biocompatibility. Thus, this thesis aimed to shed light on the optoelectronic properties of a series of melanin derivatives and apply such materials in organic devices. With this in mind, synthetic melanin derivatives were investigated using structural, optical, magnetic resonance and electrical techniques to elucidate the basic behavior of the materials as well as their charge transport properties. These set of characterizations included depth-profile X-ray photoelectron spectroscopy, photoluminescence, UV-Vis-NIR and ellipsometry spectroscopy, electron paramagnetic resonance, DC conductivity and electrochemical impedance spectroscopy under hydration control and neutron scattering. It was possible to show that soluble melanin synthesized in water behaves similarly to standard (and insoluble) melanin with slight variations that could be related small changes in the oxidation state of the samples or to different film thickness. On the other hand, the sulfonated melanin behaves like the standard one, indicating that these materials can be considered part of the “melanin family” of compounds. However, there were at least two key differences; it appears to have a lower ionic conductivity, most likely due to sulfonated groups replacing available conductive protons. However, this is compensated by the fact that sulfonated melanins exhibit easier thin-film formation on different surfaces, making it more attractive for device applications. We further demonstrated that SMel (one of the sulfonated melanin derivatives) is sensitive to pH in a carbon/graphene screen-printed electrode, that is, a sensor. This device can be considered a proof of concept that sulfonated melanin can act as transduction material for bioelectronics applications. |
publishDate |
2021 |
dc.date.none.fl_str_mv |
2021-03-16T20:06:43Z 2021-03-16T20:06:43Z 2021-02-26 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/doctoralThesis |
format |
doctoralThesis |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/11449/204105 33004056083P7 |
url |
http://hdl.handle.net/11449/204105 |
identifier_str_mv |
33004056083P7 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
Universidade Estadual Paulista (Unesp) |
publisher.none.fl_str_mv |
Universidade Estadual Paulista (Unesp) |
dc.source.none.fl_str_mv |
reponame:Repositório Institucional da UNESP instname:Universidade Estadual Paulista (UNESP) instacron:UNESP |
instname_str |
Universidade Estadual Paulista (UNESP) |
instacron_str |
UNESP |
institution |
UNESP |
reponame_str |
Repositório Institucional da UNESP |
collection |
Repositório Institucional da UNESP |
repository.name.fl_str_mv |
Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP) |
repository.mail.fl_str_mv |
|
_version_ |
1800401042483970048 |