Association of a Hydrophobically Modified Polyelectrolyte and a Block Copolymer Followed by Fluorescence Techniques
Autor(a) principal: | |
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Data de Publicação: | 2009 |
Outros Autores: | , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10316/10549 https://doi.org/10.1021/jp8093879 |
Resumo: | By using absorption and fluorescence (steady-state and time-resolved) techniques, the interaction between a poly(acrylic acid) (PAA), randomly grafted with pyrene (Py) units (PAAMePy55), and a triblock copolymer of poly(ethylene oxide) and poly(propylene oxide) (EO20PO68EO20, P123) was investigated. From the fluorescence data, it is shown that upon addition of P123 a decrease of the (pyrene−pyrene, Py−Py) intramolecular association, i.e., a decrease of dynamic and static excimer formation, is observed. Time-resolved fluorescence data reveal the existence of two types of monomers (monomers that are able to form excimer, MAGRE, and isolated monomers) and two excimers. Addition of P123 causes also an increase of the amount of isolated Py monomers. The overall fluorescence data suggest that the PAAMePy55 and the P123 block copolymer associate strongly at low pH, leading to the formation of P123 micelles surrounded by one PAAMePy55 chain, where the pyrene groups are located at the PPO/PEO interface of the P123 micelles. Steady-state fluorescence results also showed that an excess of P123 micelles in solution is required for the association to occur. At high pH (pH 9 and above) the situation is less clear. The steady-state (particularly in the I1/I3 ratio) and time-resolved fluorescence results indicate a contact between the pyrene groups and PEO, which then would imply that there may be an interaction, but much weaker than at low pH. |
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Association of a Hydrophobically Modified Polyelectrolyte and a Block Copolymer Followed by Fluorescence TechniquesBy using absorption and fluorescence (steady-state and time-resolved) techniques, the interaction between a poly(acrylic acid) (PAA), randomly grafted with pyrene (Py) units (PAAMePy55), and a triblock copolymer of poly(ethylene oxide) and poly(propylene oxide) (EO20PO68EO20, P123) was investigated. From the fluorescence data, it is shown that upon addition of P123 a decrease of the (pyrene−pyrene, Py−Py) intramolecular association, i.e., a decrease of dynamic and static excimer formation, is observed. Time-resolved fluorescence data reveal the existence of two types of monomers (monomers that are able to form excimer, MAGRE, and isolated monomers) and two excimers. Addition of P123 causes also an increase of the amount of isolated Py monomers. The overall fluorescence data suggest that the PAAMePy55 and the P123 block copolymer associate strongly at low pH, leading to the formation of P123 micelles surrounded by one PAAMePy55 chain, where the pyrene groups are located at the PPO/PEO interface of the P123 micelles. Steady-state fluorescence results also showed that an excess of P123 micelles in solution is required for the association to occur. At high pH (pH 9 and above) the situation is less clear. The steady-state (particularly in the I1/I3 ratio) and time-resolved fluorescence results indicate a contact between the pyrene groups and PEO, which then would imply that there may be an interaction, but much weaker than at low pH.American Chemical Society2009-05-07info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articlehttp://hdl.handle.net/10316/10549http://hdl.handle.net/10316/10549https://doi.org/10.1021/jp8093879engThe Journal of Physical Chemistry B. 113:18 (2009) 6194-62041520-6106Costa, TelmaSchillén, KarinMiguel, Maria da G.Lindman, BjörnMelo, J. Seixas deinfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2020-03-09T09:07:45Zoai:estudogeral.uc.pt:10316/10549Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T21:01:32.574925Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
Association of a Hydrophobically Modified Polyelectrolyte and a Block Copolymer Followed by Fluorescence Techniques |
title |
Association of a Hydrophobically Modified Polyelectrolyte and a Block Copolymer Followed by Fluorescence Techniques |
spellingShingle |
Association of a Hydrophobically Modified Polyelectrolyte and a Block Copolymer Followed by Fluorescence Techniques Costa, Telma |
title_short |
Association of a Hydrophobically Modified Polyelectrolyte and a Block Copolymer Followed by Fluorescence Techniques |
title_full |
Association of a Hydrophobically Modified Polyelectrolyte and a Block Copolymer Followed by Fluorescence Techniques |
title_fullStr |
Association of a Hydrophobically Modified Polyelectrolyte and a Block Copolymer Followed by Fluorescence Techniques |
title_full_unstemmed |
Association of a Hydrophobically Modified Polyelectrolyte and a Block Copolymer Followed by Fluorescence Techniques |
title_sort |
Association of a Hydrophobically Modified Polyelectrolyte and a Block Copolymer Followed by Fluorescence Techniques |
author |
Costa, Telma |
author_facet |
Costa, Telma Schillén, Karin Miguel, Maria da G. Lindman, Björn Melo, J. Seixas de |
author_role |
author |
author2 |
Schillén, Karin Miguel, Maria da G. Lindman, Björn Melo, J. Seixas de |
author2_role |
author author author author |
dc.contributor.author.fl_str_mv |
Costa, Telma Schillén, Karin Miguel, Maria da G. Lindman, Björn Melo, J. Seixas de |
description |
By using absorption and fluorescence (steady-state and time-resolved) techniques, the interaction between a poly(acrylic acid) (PAA), randomly grafted with pyrene (Py) units (PAAMePy55), and a triblock copolymer of poly(ethylene oxide) and poly(propylene oxide) (EO20PO68EO20, P123) was investigated. From the fluorescence data, it is shown that upon addition of P123 a decrease of the (pyrene−pyrene, Py−Py) intramolecular association, i.e., a decrease of dynamic and static excimer formation, is observed. Time-resolved fluorescence data reveal the existence of two types of monomers (monomers that are able to form excimer, MAGRE, and isolated monomers) and two excimers. Addition of P123 causes also an increase of the amount of isolated Py monomers. The overall fluorescence data suggest that the PAAMePy55 and the P123 block copolymer associate strongly at low pH, leading to the formation of P123 micelles surrounded by one PAAMePy55 chain, where the pyrene groups are located at the PPO/PEO interface of the P123 micelles. Steady-state fluorescence results also showed that an excess of P123 micelles in solution is required for the association to occur. At high pH (pH 9 and above) the situation is less clear. The steady-state (particularly in the I1/I3 ratio) and time-resolved fluorescence results indicate a contact between the pyrene groups and PEO, which then would imply that there may be an interaction, but much weaker than at low pH. |
publishDate |
2009 |
dc.date.none.fl_str_mv |
2009-05-07 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10316/10549 http://hdl.handle.net/10316/10549 https://doi.org/10.1021/jp8093879 |
url |
http://hdl.handle.net/10316/10549 https://doi.org/10.1021/jp8093879 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
The Journal of Physical Chemistry B. 113:18 (2009) 6194-6204 1520-6106 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.publisher.none.fl_str_mv |
American Chemical Society |
publisher.none.fl_str_mv |
American Chemical Society |
dc.source.none.fl_str_mv |
reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação instacron:RCAAP |
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Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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RCAAP |
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RCAAP |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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