Effect of functionalization and molecular weight of cationic dextran polyelectrolytes on the electrochemical behavior at the water/1,2-dichloroethane interface

JULIETA SOLEDAD RIVA; LIDIA MABEL YUDI

PHYSICAL CHEMISTRY CHEMICAL PHYSICS

ROYAL SOC CHEMISTRY

Lugar: CAMBRIDGE; Año: 2015 vol. 17

1463-9076

The electrochemical behaviour of several cationic dextran polyelectrolytes, aminodextran (AD), dextran cationic (CD) and diethylaminoethyl dextran (DEAE-D), at the polarized water/1,2-dichloroethane interface was studied. An investigation into the influence of scan rate, concentration, pH, the nature and the concentration of the anion present in the organic electrolyte, and the effect of the polymer molecular weight is presented. Different responses were obtained and explained considering the structural difference between these species, mainly the position of the positive charge in the macromolecule. AD polymer is not transferred to the organic phase, regardless of molecular weight, while CD and DEAE-D are transferred from the aqueous to the organic phase at E = 0.650 V, independent on the polymer concentraction and on the molecular weight. The shape of the voltammograms corresponding to DEAE-D transfer, as well as the magnitude of the peak currents and the peak potentials values were all dependent on the pH of the aqueous phase solution and on the nature and concentration on the anion present in the organic electrolyte. Based on this dependence, we postulated a mixed mechanism which involves the transfer of dissolved and adsorbed DEAE-D molecules. Keywords: Cationic dextran, Amino dextran, Diethylaminoethyl dextran, polyelectrolytes, liquid/liquid interfaces, interfacial adsorption.