Thermodynamics of the interaction between a hydrophobically modified polyelectrolyte and sodium dodecyl sulfate in aqueous solution

• Tipo: Artigo em Revista Científica Internacional
• Data: 2004

Autores

Bai, GY (Autor) Outra; Santos, LMNBF (Autor) FCUP; Nichifor, M (Autor) Outra; Lopes, A (Autor) FCUP; Bastos, M (Autor) FCUP

Revista

Título: Journal of Physical Chemistry B

Vol. 108

Páginas: 405-413

ISSN: 1520-6106

Editora: American Chemical Society

Indexação

ISI Web of Knowledge - 85 Citações

Scopus - 87 Citações

Classificação Científica

FOS: Ciências exactas e naturais > Química

Outras Informações

ID Authenticus: P-000-BZB

DOI: 10.1021/jp036377j

Abstract (EN): The thermodynamics of the interaction between a hydrophobically modified cationic polyelectrolyte and an anionic surfactant (sodium dodecyl sulfate, SDS) has been investigated by microcalorimetry, conductivity, and UV-vis spectrophotometry. The polyelectrolyte employed was a newly synthesized polymer (D40OCT30) based on dextran having pendant N-(2-hydroxypropyl)-N,N-dimethyl-N-octylammonium chloride groups randomly distributed along the polymer backbone with a degree of substitution (DS) of 28.1%. The interaction between D40OCT30 and SDS was found to be very strong because of the introduction of ionic and hydrophobic moieties on the backbone of the dextran polymer. The aggregation concentration of polyelectrolyte-SDS complex (CAC(complex)) was derived from the curves of variation of the observed enthalpy, solution conductivity, and optical dispersion with SDS concentrations. The results show that these values obtained from different methods are coincident and increase with D40OCT30 concentration. A mechanism of interaction is proposed and discussed in detail in the text. The total interaction enthalpies were derived from the observed enthalpy curves. The results indicate that the total interaction process is entropy-driven. From the calorimetric and turbidity measurements, the partial phase diagram that describes the dependence of the phase boundary on polymer alkyl side chain concentration is also deduced.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 9