Interactions between Sodium Dodecyl Sulfate and Six Nonionic Copolymers Containing 10 Mol of Different Covalently Bonded Derivatives of Vinyl Acrylic Acid: Electromotive Force and Microcalorimetry Studies

The binding of sodium dodecyl sulfate (SDS) to six random nonionic copolymers with the general chemical name polyvinyl(methyl imidazole-co-pyrrolidone-co-acrylate) were studied using electromotive force measurements (EMF) and isothermal titration calorimetry (ITC). In terms of their composition expressed in mole percent, each polymer contains 45 mol % methyl vinyl imidazole (MVI), 45 mol % vinyl pyrrolidone (VP), and 10 mol % of each of six different substituted acrylates. The purpose of the work was to investigate how subtle structural changes in the acrylate monomer affect the binding properties of SDS. The results showed significant differences in the binding behavior of the polymers, which are reflected in the determination of critical constants associated with SDS binding, like binding isotherms, the degree of sodium ion association to the bound SDS micelles, and the binding enthalpies as measured by ITC, especially in the early stages of binding. This opens the possibility of using ITC and EMF exper...