CONFORMATIONAL TRANSITIONS IN AQUEOUS-SOLUTIONS OF POLY(L-GLUTAMIC ACID) - A RADIOWAVE DIELECTRIC STUDY

The dielectric properties Of poly(L-glutamic acid) aqueous solutions during the entire conformational helix to random coil transition induced by pH have been measured in the frequency range from 1 kHz to 10 MHz. The dielectric spectra have been decomposed into two separate dielectric relaxations attributed to counterion fluctuation in the neighborhood of the polyion. The characteristic parameters underlying the counterion polarization dielectric models have been estimated. In particular, at high pH values, when the polyion is no longer in a helical conformation, some evidence is shown to attribute the high-frequency dielectric dispersion to the Maxwell-Wagner effect occurring in heterogeneous systems.