Interaction of perfluorinated ionic surfactants with polyelectrolytesTurk, Matevž (Avtor) Kogej, Ksenija (Mentor) Hansson, Per (Komentor) Polyelectrolyte-surfactant systemsperfluorinated surfactantsbinding isothermSAXSPolyelectrolyte-surfactant system models.Polyelectrolyte-surfactant systems are an active field of research due to their potential applications in pharmacy and medicine, particularly as drug delivery systems. The aim of this thesis was to investigate a specific polyelectrolyte-surfactant system comprised of sodium polystyrene sulfonate (NaPSS) and 1H,1H,2H,2H-perfluorodecylpyridinium chloride (HFDePC). The potentiometrically determined binding isotherm of this system displays a negative slope in the cooperative binding region. This phenomenon has so far been attributed to interference from the polyelectrolyte with the surfactant ion-selective electrode, but no definitive explanation has been proposed. Within the scope of this thesis, binding isotherms of the perfluorinated HFDePC and of the dodecylpyridinium chloride (DPC) to sodium polyacrylate (NaPA) and NaPSS, present either as linear polyion chains in solution or in the form of a covalently crosslinked hydrogel, were measured. The results demonstrated that the negative slope displayed by the binding isotherm of the NaPSS-HFDePC system is not an artifact of polyelectrolyte interference with the electrode but rather an intrinsic feature of the system. Furthermore, NaPSS hydrogel pieces were studied by means of small-angle X-ray scattering (SAXS) to obtain structural information about the polyelectrolyte-surfactant aggregates. Finally, thermodynamic models of the NaPSS-DPC and NaPSS-HFDePC systems were developed. Using these models, the negative slope observed in the NaPSS-HFDePC binding isotherm was attributed to a gradual relaxation of the PSS chains as surfactant binding progresses, which is a consequence of the cylindrical geometry of HFDePC micelles, as well as a phase transition of the PSS chains that occurs once a critical amount of surfactant is bound to them.20252025-01-23 12:55:02Magistrsko delo/naloga166736VisID: 24272COBISS_ID: 225336835sl