Thermodynamics of self-assembling of hydrophobically modified cationic polysaccharides and their mixtures with oppositely charged surfactants in aqueous solution

• Tipo: Artigo em Revista Científica Internacional
• Data: 2005

Autores

Bai, G (Autor) Outra; Nichifor, M (Autor) Outra; Lopes, A (Autor) FCUP; Bastos, M (Autor) FCUP

Revista

Título: Journal of Physical Chemistry B

Vol. 109

Páginas: 21681-21689

ISSN: 1520-6106

Editora: American Chemical Society

Indexação

ISI Web of Knowledge - 25 Citações

Scopus - 35 Citações

Outras Informações

ID Authenticus: P-00F-H97

DOI: 10.1021/jp054154i

Abstract (EN): Microcalorimetric techniques, combined with turbidity measurements, were used to study the thermodynamics of self-assembling of hydrophobically modified cationic polysaccharides and their mixtures with oppositely charged surfactants in aqueous solution. The studied polyelectrolytes were a series of polymers based on dextran having pendant N-(2-hydroxypropyl)-N,N-dimethyl-N-alkylammonium chloride groups randomly distributed along the polymer backbone. The parameters for their micellization process are evaluated from the results of the observed dilution enthalpy curves and compared with those of the related cationic surfactants (DTAC and CTAC). The microcalorimetric results for the mixed systems (polyelectrolytes with oppositely charged surfactants) are used along with turbidity measurements to characterize systematically the thermodynamics of their interaction. The phase behavior is described and the interaction enthalpies are derived from the differences between the observed enthalpy curves with and without polyelectrolyte. Therefore, we discuss in detail the effect of changing the alkyl chain length of polyelectrolyte pendant groups, the molecular weight of the dextran backbone, and the temperature of the measurements on the interactions between polyelectrolyte and surfactant. © 2005 American Chemical Society.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 9