| Abstract | Cilj ovog rada bio je utvrditi utjecaj zamjene halogenidnih protuiona (Br⁻ i Cl⁻) s kompleksnim protuionom koji sadrži željezo na osnovna fizikalno-kemijska svojstva strukturno različitih PAT: monomernih dodecilpiridinijeva klorida (DPC) i dodeciltrimetilamonijeva bromida (DTAB), dimerne bis(N,N-dimetil-N-dodecil)etilen-1,2-diamonijeva dibromida (12-2-12) i dvolančane didodecildimetilamonijeva bromida (DDAB). U tu svrhu sintetizirane su nove PAT s kompleksnim protuionima: (DP)[FeCl4], (12-2-12)[Fe2OBr6] i (DDA)[FeBrCl3]. Općenito, uvođenjem metalnih iona u strukture konvencionalnih PAT nastaju jedinstveni spojevi koji osim sposobnosti adsorpcije i asocijacije posjeduju redoks, magnetska, i katalitička svojstva, s naglaskom na magentskim svojstvima u slučaju ugradnje iona željeza. Praćenjem termičkih promjena novosintetiziranih PAT pomoću stolića za grijanje i polarizacijskog mikroskopa (POM) utvrđeno je da ih karakteriziraju vrlo niska tališta, bliska sobnoj temperaturi, s izuzetkom dimerne (12-2-12)[Fe2OBr6]. Time spadaju u skupinu površinski aktivnih ionskih tekućina. Otopine novosintetiziranih PAT istražene su mjerenjem površinske napetosti Du Noüyevom metodom, mjerenjem električne provodnosti, a veličina i zeta potencijal micela određeni su dinamičkim (DLS) i elektroforetskim raspršenjem svjetlosti (ELS). Dobiveni rezultati pokazali su da zamjena halogenidnih protuiona s kompleksnim protuionom koji sadrži željezo ne utječe značajno na adsorpciju i asocijaciju istraženih PAT, neovisno o strukturi površinski aktivnog kationa. Rezultati dinamičkog i elektroforetskog raspršenja svjetlosti pokazali su da monomerna (DP)[FeCl4] i dimerna (12-2-12)[Fe2OBr6] PAT pri istim koncentracijama asociraju u veće asocijate, nižeg ζ potencijala, u odnosu na odgovarajuće ishodne PAT. Suprotan trend opažen je u sustavima dvolančane PAT, (DDA)[FeBrCl3]. |
| Abstract (english) | The aim of this study was to determine the impact of substituting halide counterions (Br⁻ and Cl⁻) with a complex counterion containing iron on the physico-chemical properties of structurally different surfactants: monomeric, dodecylpyridinium chloride (DPC) and dodecyltrimethylammonium bromide (DTAB), dimeric, bis(N,N-dimethyl-N-dodecyl)ethane- 1,2-diammonium dibromide (12-2-12), and double-chained, didodecyldimethylammonium bromide (DDAB). For this purpose new surfactants were synthesized: (DP)[FeCl₄], (12-2-12)[Fe₂OBr₆], and (DDA)[FeBrCl₃]. By introducing metal ions into surfactants' structure unique compounds are created, possessing magnetic, catalytic and redox properties, in addition to their adsorption and aggregation capabilities. Special emphasises is given on magnetic properties when iron ions are introduced. Thermal properties of the investigated surfactants were monitored using a heating stage and polarized optical microscope (POM), revealing that they are characterized by very low melting points, close to room temperature, with the exception of the dimeric (12-2-12)[Fe₂OBr₆]. Therefore, the synthesized surfactants fall into the category of surfaceactive ionic liquids. The solutions of the newly synthesized surfactants were investigated by measuring surface tension using the Du Noüy method, electrical conductivity was determined, and the size and zeta potential of micelles were determined by dynamic light scattering (DLS) and electrophoretic light scattering (ELS). The obtained results showed that the substitution of halide counterions with a complex counterion containing iron does not significantly affect the adsorption and association of the studied surfactants, regardless of the structure of the surfaceactive cation. The results of dynamic and electrophoretic light scattering indicated that monomeric, (DP)[FeCl₄], and dimeric, (12-2-12)[Fe₂OBr₆], surfactants self-assemble into larger aggregates with lower ζ potential, compared to their respective parent surfactants. An opposite trend was observed in the double-chained surfactant systems, (DDA)[FeBrCl₃]. |
