A calorimetric study on interactions of amino acids with sodium dodecylsulfate and dodecyltrimethylammonium bromide in aqueous solutions at 298.15 K

Enthalpies of solution and transfer of glycine, l-alanine, l-valine, l-serine and l-threonine from water to aqueous surfactant (sodium dodecyl sulfate or dodecyltrimethylammonium bromide) solutions have been determined at 298.15 K by isothermal calorimetry. Dehydration and ion–ion interactions are important at low concentrations of the surfactant. Hydrophobic–hydrophobic interactions become primary when the amino acid molecules insert into the hydrophobic tail groups of the micelles. These phenomena can be explained with the hydration co-sphere overlap model.