Interaction of perfluorinated ionic surfactants with polyelectrolytes

Turk, Matevž (avtor), Kogej, Ksenija (mentor), Hansson, Per (komentor)

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.

• Jezik: Angleški jezik
• Ključne besede: Polyelectrolyte-surfactant systems, perfluorinated surfactants, binding isotherm, SAXS, Polyelectrolyte-surfactant system models.
• Vrsta gradiva: Magistrsko delo/naloga
• Tipologija: 2.09 - Magistrsko delo
• Organizacija: FKKT - Fakulteta za kemijo in kemijsko tehnologijo
• Leto izida: 2025
• PID: 20.500.12556/RUL-166736
• COBISS.SI-ID: 225336835
• Datum objave v RUL: 23.01.2025

Sekundarni jezik

• Jezik: Slovenski jezik
• Naslov: Interakcija perfluoriranih ionskih surfaktantov s polielektroliti

Izvleček

Sistemi polielektrolitov in surfaktantov predstavljajo atraktivno raziskovalno področje, predvsem zaradi njihove potencialne uporabnosti v farmacevtski industriji in medicini kot sistemi za tarčno dostavljanje zdravilnih učinkovin. Cilj te magistrske naloge je bil raziskati pojav, opažen v sistemu natrijevega polistirensulfonata (NaPSS) in 1H,1H,2H,2H-perfluorodecilpiridinijevega klorida (HFDePC). Vezavna izoterma tega sistema, določena z metodo potenciometrične titracije, kaže negativen naklon v področju kooperativne vezave surfaktanta. Ta pojav je bil doslej pripisan interferenci med polielektrolitom v raztopini in ionoselektivno elektrodo, vendar dokončna razlaga še ni bila predlagana. V okviru te magistrske naloge smo izmerili vezavne izoterme HFDePC in dodecilpiridinijevega klorida (DPC) na natrijev poliakrilat (NaPA) in NaPSS, ki sta bila prisotna bodisi v obliki linearnih verig v raztopini bodisi v obliki kovalentno zamreženih hidrogelov. Rezultati so pokazali, da negativen naklon vezavne izoterme sistema NaPSS-HFDePC ni artefakt interference polielektrolita s potenciometričnimi meritvami, temveč intrinzična lastnost sistema. Poleg določanja vezavnih izoterm smo vzorce NaPSS hidrogelov analizirali z uporabo ozkokotnega rentgentskega sipanja (SAXS), s čimer smo pridobili podatke o strukturi agregatov, ki jih v teh sistemih tvorijo surfaktanti s polielektroliti. Na koncu smo razvili teoretična termodinamska modela za sistema NaPSS-DPC in NaPSS-HFDePC. S pomočjo teh modelov smo negativni naklon vezavne izoterme, opažen pri sistemu NaPSS-HFDePC, pripisali postopni relaksaciji verig PSS ob vezavi surfaktanta, ki je posledica cilindrične geometrije HFDePC micel, ter faznemu prehodu verig PSS, ki nastopi, ko se nanje veže kritična količina surfaktanta.

• Ključne besede: Sistemi polielektrolitov in surfaktantov, perfluorirani surfaktanti, vezavna izoterma, SAXS, modeli sistemov polielektrolitov in surfaktantov.