D. Zanette et al., Interactions of anionic surfactants with poly(ethylene oxide) and bovine serum albumin polymers: effect of the counterion hydrophobicity, COLL SURF A, 147(1-2), 1999, pp. 89-105
Citations number
39
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
The interactions and properties of resulting complexes between poly(ethylen
e oxide) (PEO) and surfactants with different head groups, such as sulfates
, carboxylate and phosphate has been investigated. Also investigated was th
e effect of counterion for PEO-dodecyl sulfate surfactants with lithium (LD
S), sodium (SDS), cesium (CDS) and tetramethylammonium (TMADS). Special att
ention was given to the hydrophobic effect of the counterion TMA(+) on the
binding. Studies were extended to bovine serum albumin (BSA)-dodecyl sulfat
e surfactant systems which were then compared with the conventional behavio
r of the PEO-SDS system. Electrical conductance measurements were used in o
rder to characterize changes of parameters such as the critical aggregation
concentration (cac), polymer saturation point (psp), degree of ionization
and the amount of surfactant binding to polymer. The mean sizes of the aggr
egates were determined by the steady-state fluorescence quenching technique
. The results are rationalized in terms of a mechanism of interaction which
assumes that mean driving forces which, by exclusion of the others, must r
eside in the head group of surfactant and premicelles which always specific
ally coordinate with the polymer chain in those cases in which cac depressi
on occurs. Evidence of the existence of premicelle was provided by followin
g the effect of PEO concentration on the first-order rate constant-surfacta
nt concentration profiles, in the presence of SDS, of acid-catalyzed hydrol
ysis of a moderated hydrophobic substrate, di-n-butyl benzaldehyde acetal.
(C) 1999 Elsevier Science B.V. All rights reserved.