Interaction of DL-Valine/DL-Serine with Cationic and Anionic Surfactants in Aqueous Media: Volumetric, UV-visible Spectroscopic, and Conductometric Studies

In the present work, the volumetric and conductometric studies to find the interactions between amino acids DL-Valine and DL-Serine with cationic and anionic surfactants, cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulphate (SDS) in aqueous solutions at different temperatures and atmospheric pressure were carried out. The effect of pre- and post-micellar concentrations of surfactants on the physicochemical properties was also studied. The densities measured experimentally were used to calculate the thermodynamic parameters such as the apparent molar volumes, ϕ_v, partial molar volumes, \(\phi _{{\text{v}}}^{{\text{0}}}\), transfer volumes, \(\phi _{{\text{v}}}^{{\text{0}}}\) (tr), and partial molar expansibilities, \(\phi _{{\text{E}}}^{0}\) at temperatures from 288.15 to 303.15 K while the conductivity data obtained at different temperatures from 293.15 to 318.15 K were used to obtain the molar conductivities (\({{{{\Lambda }}}^{0}}\)) as well as limiting molar conductivities (\(\Lambda _{{\text{m}}}^{0}\)) from specific conductivities (κ) which reflect the interaction prevailing within the studied systems. In addition, the UV-visible absorption spectroscopy at 298.15 K has also been performed in the presence of fluorescein to study the interaction within above mentioned systems.