Influence of Frequency on Electrical Properties of Acid and Trivalent Metal Alginate Ionotropic Gels. A Correlation between Strength of Chelation and Stability of Polyelectrolyte Gels

Abstract

The influence of a wide range of frequencies (0.02-800 kHz) on the specific conductance of acid and trivalent metal alginate ionotropic gel complexes has been investigated conductimetrically. A new technique has been used to measure the electrical conductance in these gel complexes. Plots of the specific conductance vs frequency show two definite inflection points for every metal alginate gel; whereas one inflection point is observed for the acid gels. Each inflection point is located at a frequency characteristic to the corresponding alginate gel complex. This behaviour was explained by the elimination of the relaxation effects resulting from the cleavage of the hydrogen bonds in the acid gels or cleavage of the coordinate and ionic bonds in the case of the trivalent metal alginate gels. A mechanism consistent with the experimental results in terms of the strength of chelation and stability of the gel complexes is presented.