Molecular Transport in Thin Thermoresponsive Poly( N -isopropylacrylamide) Brushes with Varying Grafting Density

Autores
García, Teodoro Alonso; Gervasi, Claudio; Rodriguez Presa, Maria Jose; Otamendi, Joseba Irigoyen; Moya, Sergio E.; Azzaroni, Omar
Año de publicación
2012
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
The effect of the grafting density on the molecular transport through thermoresponsive brushes of  poly(Nisopropylacrylamide) (PNIPAM) grafted onto flat gold substrates was investigated using voltammetry and impedance spectroscopy. PNIPAM brush layers were synthesized at four different grafting densities using surface-initiated atom transfer radical polymerization (SI-ATRP) from mixed self-assembled monolayers of ω-mercaptoundecyl bromoisobutyrate and undecanethiol chemisorbed on gold surfaces. Tethered PNIPAM layers with grafting densities resulting from initiator concentrations lower than 25% in the thiol monolayer show the same transport properties as the initial self-assembled monolayer before brush synthesis. For higher grafting densities, the diffusion coefficients, D, of the K3[Fe(CN)6]/K4[Fe(CN)6] redox probe is 7 orders of magnitude smaller than those typically measured in aqueous solutions and independent of whether the brush is collapsed or swollen. The collapse of the PNIPAM brush drives a hydrophilic/hydrophobic transition in addition to structural/conformational transformations of the grafted layers, resulting in still smaller values of D. However, these changes do not lead to a blocking effect on the active area of the gold surface, which is only determined by pinholes or discontinuities in the thiol initiator monolayer. These results are only observed for thin PNIPAM brush layers.
Fil: García, Teodoro Alonso. No especifíca;
Fil: Gervasi, Claudio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina
Fil: Rodriguez Presa, Maria Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina
Fil: Otamendi, Joseba Irigoyen. No especifíca;
Fil: Moya, Sergio E.. No especifíca;
Fil: Azzaroni, Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina
Materia
molecular transport
pNIPAM brushes
grafting density
EIS AFM
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/273849
Acceder
id CONICETDig_6db87bb3dc1e518b01e94c39505e12ce
oai_identifier_str oai:ri.conicet.gov.ar:11336/273849
network_acronym_str CONICETDig
repository_id_str 3498
network_name_str CONICET Digital (CONICET)
spelling Molecular Transport in Thin Thermoresponsive Poly( N -isopropylacrylamide) Brushes with Varying Grafting DensityGarcía, Teodoro AlonsoGervasi, ClaudioRodriguez Presa, Maria JoseOtamendi, Joseba IrigoyenMoya, Sergio E.Azzaroni, Omarmolecular transportpNIPAM brushesgrafting densityEIS AFMhttps://purl.org/becyt/ford/2.10https://purl.org/becyt/ford/2The effect of the grafting density on the molecular transport through thermoresponsive brushes of  poly(Nisopropylacrylamide) (PNIPAM) grafted onto flat gold substrates was investigated using voltammetry and impedance spectroscopy. PNIPAM brush layers were synthesized at four different grafting densities using surface-initiated atom transfer radical polymerization (SI-ATRP) from mixed self-assembled monolayers of ω-mercaptoundecyl bromoisobutyrate and undecanethiol chemisorbed on gold surfaces. Tethered PNIPAM layers with grafting densities resulting from initiator concentrations lower than 25% in the thiol monolayer show the same transport properties as the initial self-assembled monolayer before brush synthesis. For higher grafting densities, the diffusion coefficients, D, of the K3[Fe(CN)6]/K4[Fe(CN)6] redox probe is 7 orders of magnitude smaller than those typically measured in aqueous solutions and independent of whether the brush is collapsed or swollen. The collapse of the PNIPAM brush drives a hydrophilic/hydrophobic transition in addition to structural/conformational transformations of the grafted layers, resulting in still smaller values of D. However, these changes do not lead to a blocking effect on the active area of the gold surface, which is only determined by pinholes or discontinuities in the thiol initiator monolayer. These results are only observed for thin PNIPAM brush layers.Fil: García, Teodoro Alonso. No especifíca;Fil: Gervasi, Claudio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Rodriguez Presa, Maria Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Otamendi, Joseba Irigoyen. No especifíca;Fil: Moya, Sergio E.. No especifíca;Fil: Azzaroni, Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaAmerican Chemical Society2012-06info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/273849García, Teodoro Alonso; Gervasi, Claudio; Rodriguez Presa, Maria Jose; Otamendi, Joseba Irigoyen; Moya, Sergio E.; et al.; Molecular Transport in Thin Thermoresponsive Poly( N -isopropylacrylamide) Brushes with Varying Grafting Density; American Chemical Society; Journal of Physical Chemistry C; 116; 26; 6-2012; 13944-139531932-7447CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/url/https://pubs.acs.org/doi/10.1021/jp301621yinfo:eu-repo/semantics/altIdentifier/doi/10.1021/jp301621yinfo:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-12-03T08:57:25Zoai:ri.conicet.gov.ar:11336/273849instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-12-03 08:57:25.775CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv Molecular Transport in Thin Thermoresponsive Poly( N -isopropylacrylamide) Brushes with Varying Grafting Density
title Molecular Transport in Thin Thermoresponsive Poly( N -isopropylacrylamide) Brushes with Varying Grafting Density
spellingShingle Molecular Transport in Thin Thermoresponsive Poly( N -isopropylacrylamide) Brushes with Varying Grafting Density
García, Teodoro Alonso
molecular transport
pNIPAM brushes
grafting density
EIS AFM
title_short Molecular Transport in Thin Thermoresponsive Poly( N -isopropylacrylamide) Brushes with Varying Grafting Density
title_full Molecular Transport in Thin Thermoresponsive Poly( N -isopropylacrylamide) Brushes with Varying Grafting Density
title_fullStr Molecular Transport in Thin Thermoresponsive Poly( N -isopropylacrylamide) Brushes with Varying Grafting Density
title_full_unstemmed Molecular Transport in Thin Thermoresponsive Poly( N -isopropylacrylamide) Brushes with Varying Grafting Density
title_sort Molecular Transport in Thin Thermoresponsive Poly( N -isopropylacrylamide) Brushes with Varying Grafting Density
dc.creator.none.fl_str_mv García, Teodoro Alonso
Gervasi, Claudio
Rodriguez Presa, Maria Jose
Otamendi, Joseba Irigoyen
Moya, Sergio E.
Azzaroni, Omar
author García, Teodoro Alonso
author_facet García, Teodoro Alonso
Gervasi, Claudio
Rodriguez Presa, Maria Jose
Otamendi, Joseba Irigoyen
Moya, Sergio E.
Azzaroni, Omar
author_role author
author2 Gervasi, Claudio
Rodriguez Presa, Maria Jose
Otamendi, Joseba Irigoyen
Moya, Sergio E.
Azzaroni, Omar
author2_role author
author
author
author
author
dc.subject.none.fl_str_mv molecular transport
pNIPAM brushes
grafting density
EIS AFM
topic molecular transport
pNIPAM brushes
grafting density
EIS AFM
purl_subject.fl_str_mv https://purl.org/becyt/ford/2.10
https://purl.org/becyt/ford/2
dc.description.none.fl_txt_mv The effect of the grafting density on the molecular transport through thermoresponsive brushes of  poly(Nisopropylacrylamide) (PNIPAM) grafted onto flat gold substrates was investigated using voltammetry and impedance spectroscopy. PNIPAM brush layers were synthesized at four different grafting densities using surface-initiated atom transfer radical polymerization (SI-ATRP) from mixed self-assembled monolayers of ω-mercaptoundecyl bromoisobutyrate and undecanethiol chemisorbed on gold surfaces. Tethered PNIPAM layers with grafting densities resulting from initiator concentrations lower than 25% in the thiol monolayer show the same transport properties as the initial self-assembled monolayer before brush synthesis. For higher grafting densities, the diffusion coefficients, D, of the K3[Fe(CN)6]/K4[Fe(CN)6] redox probe is 7 orders of magnitude smaller than those typically measured in aqueous solutions and independent of whether the brush is collapsed or swollen. The collapse of the PNIPAM brush drives a hydrophilic/hydrophobic transition in addition to structural/conformational transformations of the grafted layers, resulting in still smaller values of D. However, these changes do not lead to a blocking effect on the active area of the gold surface, which is only determined by pinholes or discontinuities in the thiol initiator monolayer. These results are only observed for thin PNIPAM brush layers.
Fil: García, Teodoro Alonso. No especifíca;
Fil: Gervasi, Claudio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina
Fil: Rodriguez Presa, Maria Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina
Fil: Otamendi, Joseba Irigoyen. No especifíca;
Fil: Moya, Sergio E.. No especifíca;
Fil: Azzaroni, Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina
description The effect of the grafting density on the molecular transport through thermoresponsive brushes of  poly(Nisopropylacrylamide) (PNIPAM) grafted onto flat gold substrates was investigated using voltammetry and impedance spectroscopy. PNIPAM brush layers were synthesized at four different grafting densities using surface-initiated atom transfer radical polymerization (SI-ATRP) from mixed self-assembled monolayers of ω-mercaptoundecyl bromoisobutyrate and undecanethiol chemisorbed on gold surfaces. Tethered PNIPAM layers with grafting densities resulting from initiator concentrations lower than 25% in the thiol monolayer show the same transport properties as the initial self-assembled monolayer before brush synthesis. For higher grafting densities, the diffusion coefficients, D, of the K3[Fe(CN)6]/K4[Fe(CN)6] redox probe is 7 orders of magnitude smaller than those typically measured in aqueous solutions and independent of whether the brush is collapsed or swollen. The collapse of the PNIPAM brush drives a hydrophilic/hydrophobic transition in addition to structural/conformational transformations of the grafted layers, resulting in still smaller values of D. However, these changes do not lead to a blocking effect on the active area of the gold surface, which is only determined by pinholes or discontinuities in the thiol initiator monolayer. These results are only observed for thin PNIPAM brush layers.
publishDate 2012
dc.date.none.fl_str_mv 2012-06
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/11336/273849
García, Teodoro Alonso; Gervasi, Claudio; Rodriguez Presa, Maria Jose; Otamendi, Joseba Irigoyen; Moya, Sergio E.; et al.; Molecular Transport in Thin Thermoresponsive Poly( N -isopropylacrylamide) Brushes with Varying Grafting Density; American Chemical Society; Journal of Physical Chemistry C; 116; 26; 6-2012; 13944-13953
1932-7447
CONICET Digital
CONICET
url http://hdl.handle.net/11336/273849
identifier_str_mv García, Teodoro Alonso; Gervasi, Claudio; Rodriguez Presa, Maria Jose; Otamendi, Joseba Irigoyen; Moya, Sergio E.; et al.; Molecular Transport in Thin Thermoresponsive Poly( N -isopropylacrylamide) Brushes with Varying Grafting Density; American Chemical Society; Journal of Physical Chemistry C; 116; 26; 6-2012; 13944-13953
1932-7447
CONICET Digital
CONICET
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/url/https://pubs.acs.org/doi/10.1021/jp301621y
info:eu-repo/semantics/altIdentifier/doi/10.1021/jp301621y
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
eu_rights_str_mv openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.format.none.fl_str_mv application/pdf
application/pdf
application/pdf
application/pdf
dc.publisher.none.fl_str_mv American Chemical Society
publisher.none.fl_str_mv American Chemical Society
dc.source.none.fl_str_mv reponame:CONICET Digital (CONICET)
instname:Consejo Nacional de Investigaciones Científicas y Técnicas
reponame_str CONICET Digital (CONICET)
collection CONICET Digital (CONICET)
instname_str Consejo Nacional de Investigaciones Científicas y Técnicas
repository.name.fl_str_mv CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicas
repository.mail.fl_str_mv dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar
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score 13.214268

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