Dielectric study of local relaxations in dendritic macromolecules

The aim of this work is to characterize the dielectric properties of amorphous dendritic macromolecules as a function of architectural complexity. By combining thermostimulated currents and dynamic dielectric spectroscopy, the dielectric permittivity has been obtained as a function of temperature, in a very broad frequency range (10(-4)-10(6) Hz). Generations g = 0 to g == 2 were investigated. The molecular origin of the quasi-Debye mode observed for g = 0 at low temperature is common to all generations: localized reorientations of aldehyde end groups. The interactions with the phosphorus/sulfur (P = S) dipoles are probably responsible for the broadening pointed out in upper generations.