Semi-empirical treatment of ionophore-assisted ion-transfers in ultrathin membranes coupled to a redox conducting polymer
Fecha
2021Disciplina/s
FarmaciaMateria/s
Ultrathin ion-selective membranesIon transfer
Charge transfer
Spectroelectrochemistry
Ion-ionophore interactions
Resumen
Applying spectroelectrochemistry to all-solid-state electrodes composed of poly(3-octylthiophene) (POT) and an ultrathin ion-selective membrane on top, it is possible to monitor the dynamic charge transfer (CT) in POT when this event is coupled to ion transfers (ITs) promoted by the absence/presence of a selective ionophore in the membrane. Herein, we report on a combination of empirical and theoretical evidence revealing that different molar ratios of the ionophore and the cation exchanger in the membrane result in the modulation of non-assisted and assisted ITs of different stoichiometries. This occurs upon the same anodic voltammetric scan. The use of the developed theory together with Sigmoidal−Boltzmann fittings of the experimental dynamic absorbance observed in the POT film permits calculating voltammograms with different ITs. An easy semi-empirical treatment additionally provides the calculation of binding constants related to the assisted transfers. Furthermore, the approach is...