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Pluronic F127 EO97PO69EO97; Angle neutron-scattering; Ion-selective electrodes; Light-scattering; Titration microcalorimetry; Cationic surfactants; Aqueous-solutions; Polymers; Binding; Poly(vinylpyrrolidone)
Abstract:
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)1 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 experiments which effectively measure the binding process as a mean of monitoring and characterizing subtle differences in structurally related macromolecules.
