SELF-ASSEMBLY OF TRIBLOCK COPOLYMERS IN AQUEOUS SOLUTION

Urbano, B; Silva P.; Olea, AF; Fuentes, I.; Martinez F.

Abstract

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.

Más información

Título según WOS: Self-assembly of triblock copolymers in aqueous solution
Título según SCOPUS: Self-assembly of triblock copolymers in aqueous solution
Título según SCIELO: SELF-ASSEMBLY OF TRIBLOCK COPOLYMERS IN AQUEOUS SOLUTION
Título de la Revista: JOURNAL OF THE CHILEAN CHEMICAL SOCIETY
Volumen: 53
Número: 2
Editorial: 2013
Fecha de publicación: 2008
Página de inicio: 1507
Página final: 1510
Idioma: English
DOI:

10.4067/S0717-97072008000200013

Notas: ISI, SCIELO, SCOPUS