Interaction of Short Chain Phenylalkanoic Acids Within Cationic and Anionic Surfactants

Short chain phenylalkanoic acids have been investigated by UV spectroscopy to ascertain their solubilization into cationic surfactant, cetyltrimethylammonium bromide (CTAB), and anionic surfactant, sodium dodecyl sulfate (SDS). The increasing surfactant concentrations caused bathochromic shift in the spectra of additive acids. CTAB exhibited greater lambda(max) shift, whereas lambda(max) values are slightly altered in SDS solution. Moreover, the critical micelle concentration (CMC) of CTAB with and without phenylalkanoic acids was determined by conductivity measurements. The lambda(max) and CMC data were used to calculate the electronic transition energy (Delta E (T)) and Gibbs free energy change of micellization of CTAB in presence of additive acids.