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

• Type: Article in International Scientific Journal
• Date: 2004

Authors

Bai, GY (Author) Other; Santos, LMNBF (Author) FCUP; Nichifor, M (Author) Other; Lopes, A (Author) FCUP; Bastos, M (Author) FCUP

Journal

Title: Journal of Physical Chemistry B

Vol. 108

Pages: 405-413

ISSN: 1520-6106

Publisher: American Chemical Society

Indexing

ISI Web of Knowledge - 85 Citations

Scopus - 87 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: 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.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 9