L. Bromberg et M. Temchenko, Solubilization of hydrophobic compounds by micellar solutions of hydrophobically modified polyelectrolytes, LANGMUIR, 15(25), 1999, pp. 8627-8632
Solubilization of pyrene and steroid hormones into aqueous solutions of an
associative polymer, poly(ethylene oxide)-b-poly(propylene oxide)-b-(poly(e
thylene oxide))-g-poly(acrylic acid) (Pluronic-PAA), has been studied. A dr
amatic increase of solubilization is observed upon formation of micelles ab
ove the critical micellization temperature (cmt). The equilibrium partition
coefficients of the probes between micelles and water (K-m/w) above the cm
t strongly correlate with the probe's octanol/water partition coefficient (
K-o/w). The K-m/w is increased with the ionization degree of the poly(acryl
ic acid) (PAA) segments. Preferential solubilization of the increasingly hy
drophobic compounds into the Pluronic-PAA is dominated by the entropic effe
ct. Comparison of the fraction of the probe located in the hydrophobic core
s of the micellar aggregates for pyrene and estradiol illustrates the degre
e of chemical specificity of the Pluronic-PAA micellar aggregates, which is
due to the hydrophobicity of the probe.