Low-Frequency Dielectric Relaxation of Polyelectrolyte Gels

The complex dielectric constant ε* of the poly(sodium 2-acrylamido-2-methylpropanesulfonate) (PNaAMPS) gels and their corresponding linear polymer solutions have been measured at 25 °C in a frequency range of 50−100 kHz. The polyelectrolyte gels showed a low-frequency dielectric relaxation in a frequency region lower than that of linear polymer solutions. Furthermore, the mean relaxation time τ 0 of the gel decreases with increasing the cross-linking density or the concentration. This is quite different from the behavior of the linear polymer solution, which showed a constant value of relaxation time upon changing the polymer concentration. By comparing with the linear polymer solution, the effect of the cross-linkage on the dielectric relaxation of bound counterions has been discussed.