SELF-ASSEMBLY OF TRIBLOCK COPOLYMERS IN AQUEOUS SOLUTION

The aggregation of PE4VP-b-PS-b-PE4VP block copolymers was studied in aqueous solution. Triblock copolymers P4VP-b-PS-b-P4VP were synthesized by sequential anionic polymerization of poly(styrene) and poly(4-vinylpirydine) using sodium naphthalene as a bifunctional initiator. Subsequently, the 4-viny...

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Autores principales:	URBANO,BRUNO, SILVA,PATRICIO, OLEA,ANDRÉS F, FUENTES,IRMA, MARTINEZ,FRANCISCO
Lenguaje:	English
Publicado:	Sociedad Chilena de Química 2008
Materias:	Triblock copolymers critical micelle concentration micelles fluorescence probing methods pyrene
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072008000200013
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spelling	oai:scielo:S0717-970720080002000132009-06-09SELF-ASSEMBLY OF TRIBLOCK COPOLYMERS IN AQUEOUS SOLUTIONURBANO,BRUNOSILVA,PATRICIOOLEA,ANDRÉS FFUENTES,IRMAMARTINEZ,FRANCISCO Triblock copolymers critical micelle concentration micelles fluorescence probing methods pyrene The aggregation of PE4VP-b-PS-b-PE4VP block copolymers was studied in aqueous solution. Triblock copolymers P4VP-b-PS-b-P4VP were synthesized by sequential anionic polymerization of poly(styrene) and poly(4-vinylpirydine) using sodium naphthalene as a bifunctional initiator. Subsequently, the 4-vinylpyridine units were quaternized with ethyl bromide to obtain cationic PE4VP-b-PS-b-PE4VP block copolymers. Both star and crew-cut micelles were formed. The concentrations at which micelles are formed cmc were determined, by steady-state and time-resolved fluorescence probing methods, as a function of quatemization degree. The results indicate that cmc of crew-cut micelles increases with increasing charge density of the PE4VP blocks. For star micelles there is not a clear dependency of cmc with the percentage of quatemization. The lifetime of pyrene fluorescence and the ratio I1/I3 were determined at concentrations of copolymers well above the cmc, and the results show that the location of pyrene into the micelle changes with the charge density of the micelle corona. The micropolarity sensed by pyrene decreases with increasing quatemization degree. The presence of aggregates was confirmed by transmission electronic microscopy.info:eu-repo/semantics/openAccessSociedad Chilena de QuímicaJournal of the Chilean Chemical Society v.53 n.2 20082008-06-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072008000200013en10.4067/S0717-97072008000200013
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	Triblock copolymers critical micelle concentration micelles fluorescence probing methods pyrene
spellingShingle	Triblock copolymers critical micelle concentration micelles fluorescence probing methods pyrene URBANO,BRUNO SILVA,PATRICIO OLEA,ANDRÉS F FUENTES,IRMA MARTINEZ,FRANCISCO SELF-ASSEMBLY OF TRIBLOCK COPOLYMERS IN AQUEOUS SOLUTION
description	The aggregation of PE4VP-b-PS-b-PE4VP block copolymers was studied in aqueous solution. Triblock copolymers P4VP-b-PS-b-P4VP were synthesized by sequential anionic polymerization of poly(styrene) and poly(4-vinylpirydine) using sodium naphthalene as a bifunctional initiator. Subsequently, the 4-vinylpyridine units were quaternized with ethyl bromide to obtain cationic PE4VP-b-PS-b-PE4VP block copolymers. Both star and crew-cut micelles were formed. The concentrations at which micelles are formed cmc were determined, by steady-state and time-resolved fluorescence probing methods, as a function of quatemization degree. The results indicate that cmc of crew-cut micelles increases with increasing charge density of the PE4VP blocks. For star micelles there is not a clear dependency of cmc with the percentage of quatemization. The lifetime of pyrene fluorescence and the ratio I1/I3 were determined at concentrations of copolymers well above the cmc, and the results show that the location of pyrene into the micelle changes with the charge density of the micelle corona. The micropolarity sensed by pyrene decreases with increasing quatemization degree. The presence of aggregates was confirmed by transmission electronic microscopy.
author	URBANO,BRUNO SILVA,PATRICIO OLEA,ANDRÉS F FUENTES,IRMA MARTINEZ,FRANCISCO
author_facet	URBANO,BRUNO SILVA,PATRICIO OLEA,ANDRÉS F FUENTES,IRMA MARTINEZ,FRANCISCO
author_sort	URBANO,BRUNO
title	SELF-ASSEMBLY OF TRIBLOCK COPOLYMERS IN AQUEOUS SOLUTION
title_short	SELF-ASSEMBLY OF TRIBLOCK COPOLYMERS IN AQUEOUS SOLUTION
title_full	SELF-ASSEMBLY OF TRIBLOCK COPOLYMERS IN AQUEOUS SOLUTION
title_fullStr	SELF-ASSEMBLY OF TRIBLOCK COPOLYMERS IN AQUEOUS SOLUTION
title_full_unstemmed	SELF-ASSEMBLY OF TRIBLOCK COPOLYMERS IN AQUEOUS SOLUTION
title_sort	self-assembly of triblock copolymers in aqueous solution
publisher	Sociedad Chilena de Química
publishDate	2008
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072008000200013
work_keys_str_mv	AT urbanobruno selfassemblyoftriblockcopolymersinaqueoussolution AT silvapatricio selfassemblyoftriblockcopolymersinaqueoussolution AT oleaandresf selfassemblyoftriblockcopolymersinaqueoussolution AT fuentesirma selfassemblyoftriblockcopolymersinaqueoussolution AT martinezfrancisco selfassemblyoftriblockcopolymersinaqueoussolution
_version_	1718445387390386176

SELF-ASSEMBLY OF TRIBLOCK COPOLYMERS IN AQUEOUS SOLUTION

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