Journal of the Serbian Chemical Society 2012 Volume 77, Issue 2, Pages: 201-210
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Interactions of short chain phenylalkanoic acids within ionic surfactant micelles in aqueous media
Naeem Kashif, Shah Syed W.H., Naseem Bushra, Shah Syed S.
Solubilization and interactions of phenylalkanoic acids induced by cationic
surfactant, cetyltrimethylammonium bromide (CTAB) and an anionic surfactant,
sodium dodecyl sulfate (SDS) was investigated spectrophotometrically at
25.0°C. The UV spectra of the additives (acids) were measured with and
without surfactant above and below critical micelle concentration (cmc) of
the surfactant. The presence of alkyl chain in phenylalkanoic acids is
responsible for hydrophobic interaction resulting in shift of the spectra
towards longer wavelength (red shift). The value of partition coefficient
(Kx) between the bulk water and surfactant micelles and in turn standard free
energy change of solubilization (ΔGpº) were also estimated by measuring the
differential absorbance (ΔA) of the additives in micellar solutions.
Keywords: alkanoic acids, solubilization, cmc, CT