IONIC-CONDUCTIVITY STUDIES ON SALT POLYZWITTERION SYSTEMS

In this work, the results for the ionic conductivity properties on zwitterionic polymers of the sulfobetaine type are presented. The polymers include various structures of the inner-salt kind resulting from chemical modification of precursor nonionic polymers. Measurements performed on pure polymer samples and polymer-salt mixtures are carried out by the ac spectroscopy technique, and the analysis of the results is made through complex impedance curves. Salts used include sodium iodide, lithium perchlorate, and sodium tetraphenylborate at several concentrations (0-1 M). Variations of conductivity with temperature follow an Arrhenius behavior, with values found within the range from 10(-6) to 10(-4) S cm-1. The highest values correspond to the pure polymer samples and also to the equimolar mixture. Dielectric relaxation studies included analyses of the real and imaginary parts of the impedance as a function of frequency in the range from 5 Hz to 13 MHz. The results show a Debye-type behavior within 0.2-0.8 M salt concentration and significant deviations for the pure polymer and the equimolar mixture.