Interactions between catanionic vesicles and oppositely charged poly electrolytes-phase behavior and phase structure

• Tipo: Artigo em Revista Científica Internacional
• Data: 1999

Autores

Marques, EF (Autor) FCUP; Regev, O (Autor) Outra; Khan, A (Autor) Outra; Miguel, MD (Autor) Outra; Lindman, B (Autor) Outra

Revista

Título: Macromolecules

Vol. 32

Páginas: 6626-6637

ISSN: 0024-9297

Editora: American Chemical Society

Indexação

ISI Web of Knowledge - 101 Citações

Scopus - 108 Citações

Classificação Científica

FOS: Ciências exactas e naturais > Química

Outras Informações

ID Authenticus: P-001-33G

DOI: 10.1021/ma990350+

Abstract (EN): Structural and phase behavior effects resulting from the addition of a polyelectrolyte to a solution of oppositely charged vesicles are investigated in this work. Two cationic polyelectrolytes derived from hydroxyethylcellulose were used: JR400, a homopolymer, and Quatrisoft LM200, a polymer modified with alkyl side chains. The vesicles are composed of mixed anionic surfactant (sodium dodecyl sulfate) and cationic surfactant (didodecyldimethylammonium bromide), bearing 29 mol % of the caf;ionic amphiphile. The phase behavior for the two mixed polymer-surfactant systems was investigated for polymer concentrations between 0.001 and 3 wt%. Three main regions were found in the two-phase maps, upon polymer addition: (i) a bluish solution phase; (ii) a wide region of phase separation, containing a precipitate and a solution; and (iii) a polymer-rich gel region, forming upon charge reversal of the system. Cryo-TEM imaging of the solution phase shows the formation of faceted vesicles and disklike aggregates, upon addition of JR400. Fbr the LM200 system, besides the formation of faceted vesicles, clusters of vesicles and other bilayer structures are imaged. In the polymer-rich phase of JR400, membrane fragments, disklike aggregates, and vesicles are also found. These bilayer aggregates are likely to be involved with the polymer in highly connected networks, giving rise to the observed bluish gels. Electrostatic interactions, reinforced by hydrophobic interactions in the case of LM200, are the main driving force for the structural transitions observed.

Idioma: Inglês

Tipo (Avaliação Docente): Científica