POLARIZATION PROCESSES OF POLY(DMDAAC) FILMS STUDIED BY THERMALLY STIMULATED DEPOLARIZATION CURRENT

The thermally stimulated depolarization current (TSDC) in the range of 250 to 400 K and d.c. conduction of poly (dimethyldiallylammonium chl oride) (poly(DMDAAC)) were investigated in vacuum to obtain informatio n about the type and the behavior of the polarization and the conducti on processes, especially dependence on molecular mass and electrical f ield strength. The TSDC spectrum shows one peak with Arrhenius charact er up to 316 K but deviates from it at higher temperature. A maximum d ielectric response was observed at a molecular mass of 110 000 g mol(- 1). Activation energies of about 0.45 eV for polarization currents and 0.85 eV for conduction currents were obtained. The released charge Q depends on the voltage U following the power law, Q proportional to U- 1.2. For the conduction current, I proportional to U-1.5 was obtained. The polarization was caused mainly by a dipolar process, with some co ntribution from charge carriers.