Photo-oxidation of polyphenylenevinylene chains in Langmuir-Blodgett and cast films
Autor(a) principal: | |
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Data de Publicação: | 2005 |
Outros Autores: | , |
Tipo de documento: | Artigo de conferência |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UNESP |
Texto Completo: | http://dx.doi.org/10.1109/ISE.2005.1612327 http://hdl.handle.net/11449/68528 |
Resumo: | Poly(p-phenylene vinylene) (PPV) derivatives are well known for their applications in polymer light emitting diodes (PLEDs). These derivatives are highly susceptible to photooxidation though, which is mainly caused by the scission of the vinyl double bond on the polymer backbone. In this work, we show that Langmuir-Blodgett (LB) films are less degraded than cast films of a PPV derivative (OC1OC6-PPV). Both films had similar thickness (∼50 nm) to allow for a more realistic comparison. Photodegradation experiments were carried out by illuminating the films with white light from a halogen lamp (50W, 12 V), placed at a fixed dstance from the sample. The decay was monitored by UV-Vis and FTIR spectroscopies. The results showed that cast films are completely degraded in ca. 300 min, while LB took longer times, ca. 1000 min, i.e. 3 times the values for the cast films. The degradation process occurs in at least two stages, the rates of which were calculated assuming that the reaction follows a first order kinetics. The characteristic times for the first stage were 3.6×10-2 and 1.3×10-3 min-1 for cast and LB films, respectively. For the second stage the characteristic times were 5.6×10-2 and 5.0×10 -3 min-1. The differences can be attributed to the more compact morphology in the LB than in the cast films. With a compact morphology the diffusion of oxygen in the LB film is hampered and this causes a delay in the degradation process. |
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Photo-oxidation of polyphenylenevinylene chains in Langmuir-Blodgett and cast filmsChemical bondsDerivativesFilm thicknessOrganic light emitting diodes (OLED)PhotodegradationPhotooxidationPolymer filmsCast filmsHalogen lampsPolymer backbonePolyphenylenevinyleneLangmuir Blodgett filmsPoly(p-phenylene vinylene) (PPV) derivatives are well known for their applications in polymer light emitting diodes (PLEDs). These derivatives are highly susceptible to photooxidation though, which is mainly caused by the scission of the vinyl double bond on the polymer backbone. In this work, we show that Langmuir-Blodgett (LB) films are less degraded than cast films of a PPV derivative (OC1OC6-PPV). Both films had similar thickness (∼50 nm) to allow for a more realistic comparison. Photodegradation experiments were carried out by illuminating the films with white light from a halogen lamp (50W, 12 V), placed at a fixed dstance from the sample. The decay was monitored by UV-Vis and FTIR spectroscopies. The results showed that cast films are completely degraded in ca. 300 min, while LB took longer times, ca. 1000 min, i.e. 3 times the values for the cast films. The degradation process occurs in at least two stages, the rates of which were calculated assuming that the reaction follows a first order kinetics. The characteristic times for the first stage were 3.6×10-2 and 1.3×10-3 min-1 for cast and LB films, respectively. For the second stage the characteristic times were 5.6×10-2 and 5.0×10 -3 min-1. The differences can be attributed to the more compact morphology in the LB than in the cast films. With a compact morphology the diffusion of oxygen in the LB film is hampered and this causes a delay in the degradation process.Faculdade de Ciências e Tecnologia Unesp, CP 467, 19060-900,Presidente Prudente, SPInstituto de Física de São Carlos USP, CP 369, 13560-970, São Carlos, SPFaculdade de Ciências e Tecnologia Unesp, CP 467, 19060-900,Presidente Prudente, SPUniversidade Estadual Paulista (Unesp)Universidade de São Paulo (USP)Ferreira, Marystela [UNESP]Olivati, Clarissa A. [UNESP]Balogh, Débora T.2014-05-27T11:21:41Z2014-05-27T11:21:41Z2005-12-01info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/conferenceObject95-96http://dx.doi.org/10.1109/ISE.2005.1612327Proceedings - International Symposium on Electrets, v. 2005, p. 95-96.http://hdl.handle.net/11449/6852810.1109/ISE.2005.1612327WOS:0002367645000242-s2.0-3384773302898222128086514150000-0002-0114-6795Scopusreponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPengProceedings - International Symposium on Electretsinfo:eu-repo/semantics/openAccess2024-06-19T12:46:01Zoai:repositorio.unesp.br:11449/68528Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestopendoar:29462024-08-05T17:08:23.133275Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false |
dc.title.none.fl_str_mv |
Photo-oxidation of polyphenylenevinylene chains in Langmuir-Blodgett and cast films |
title |
Photo-oxidation of polyphenylenevinylene chains in Langmuir-Blodgett and cast films |
spellingShingle |
Photo-oxidation of polyphenylenevinylene chains in Langmuir-Blodgett and cast films Ferreira, Marystela [UNESP] Chemical bonds Derivatives Film thickness Organic light emitting diodes (OLED) Photodegradation Photooxidation Polymer films Cast films Halogen lamps Polymer backbone Polyphenylenevinylene Langmuir Blodgett films |
title_short |
Photo-oxidation of polyphenylenevinylene chains in Langmuir-Blodgett and cast films |
title_full |
Photo-oxidation of polyphenylenevinylene chains in Langmuir-Blodgett and cast films |
title_fullStr |
Photo-oxidation of polyphenylenevinylene chains in Langmuir-Blodgett and cast films |
title_full_unstemmed |
Photo-oxidation of polyphenylenevinylene chains in Langmuir-Blodgett and cast films |
title_sort |
Photo-oxidation of polyphenylenevinylene chains in Langmuir-Blodgett and cast films |
author |
Ferreira, Marystela [UNESP] |
author_facet |
Ferreira, Marystela [UNESP] Olivati, Clarissa A. [UNESP] Balogh, Débora T. |
author_role |
author |
author2 |
Olivati, Clarissa A. [UNESP] Balogh, Débora T. |
author2_role |
author author |
dc.contributor.none.fl_str_mv |
Universidade Estadual Paulista (Unesp) Universidade de São Paulo (USP) |
dc.contributor.author.fl_str_mv |
Ferreira, Marystela [UNESP] Olivati, Clarissa A. [UNESP] Balogh, Débora T. |
dc.subject.por.fl_str_mv |
Chemical bonds Derivatives Film thickness Organic light emitting diodes (OLED) Photodegradation Photooxidation Polymer films Cast films Halogen lamps Polymer backbone Polyphenylenevinylene Langmuir Blodgett films |
topic |
Chemical bonds Derivatives Film thickness Organic light emitting diodes (OLED) Photodegradation Photooxidation Polymer films Cast films Halogen lamps Polymer backbone Polyphenylenevinylene Langmuir Blodgett films |
description |
Poly(p-phenylene vinylene) (PPV) derivatives are well known for their applications in polymer light emitting diodes (PLEDs). These derivatives are highly susceptible to photooxidation though, which is mainly caused by the scission of the vinyl double bond on the polymer backbone. In this work, we show that Langmuir-Blodgett (LB) films are less degraded than cast films of a PPV derivative (OC1OC6-PPV). Both films had similar thickness (∼50 nm) to allow for a more realistic comparison. Photodegradation experiments were carried out by illuminating the films with white light from a halogen lamp (50W, 12 V), placed at a fixed dstance from the sample. The decay was monitored by UV-Vis and FTIR spectroscopies. The results showed that cast films are completely degraded in ca. 300 min, while LB took longer times, ca. 1000 min, i.e. 3 times the values for the cast films. The degradation process occurs in at least two stages, the rates of which were calculated assuming that the reaction follows a first order kinetics. The characteristic times for the first stage were 3.6×10-2 and 1.3×10-3 min-1 for cast and LB films, respectively. For the second stage the characteristic times were 5.6×10-2 and 5.0×10 -3 min-1. The differences can be attributed to the more compact morphology in the LB than in the cast films. With a compact morphology the diffusion of oxygen in the LB film is hampered and this causes a delay in the degradation process. |
publishDate |
2005 |
dc.date.none.fl_str_mv |
2005-12-01 2014-05-27T11:21:41Z 2014-05-27T11:21:41Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/conferenceObject |
format |
conferenceObject |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://dx.doi.org/10.1109/ISE.2005.1612327 Proceedings - International Symposium on Electrets, v. 2005, p. 95-96. http://hdl.handle.net/11449/68528 10.1109/ISE.2005.1612327 WOS:000236764500024 2-s2.0-33847733028 9822212808651415 0000-0002-0114-6795 |
url |
http://dx.doi.org/10.1109/ISE.2005.1612327 http://hdl.handle.net/11449/68528 |
identifier_str_mv |
Proceedings - International Symposium on Electrets, v. 2005, p. 95-96. 10.1109/ISE.2005.1612327 WOS:000236764500024 2-s2.0-33847733028 9822212808651415 0000-0002-0114-6795 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
Proceedings - International Symposium on Electrets |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
95-96 |
dc.source.none.fl_str_mv |
Scopus 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 |
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1808128760774393856 |