High dielectric constant values in some polyampholytes as observed by thermally stimulated depolarization

Thermally stimulated depolarization currents of three aromatic and three aliphatic poly(sulphopropylbetaines) are described in the range −190 to +180°C. No particular relaxation common to all six polymers due to the presence of the zwitterionic group is revealed at low temperatures. A peak in the 100–170°C region occurs for all the samples. It is related to a glass transition in two cases. Very high dielectric constant increments, Δε > 100, are obtained for this peak in four cases. For these hygroscopic polymers water acts as a plasticizer for this peak without changing Δε.