Dielectric properties of polymers with fractal architecture

A set of phosphorus-containing dendrimers involving three generations (g = 0, 1 and 2) has been investigated using dynamic dielectric spectroscopy and thermostimulated currents techniques. The dendrimers show a low temperature β mode with an Arrhenius type temperature dependence. Havriliak-Negami parameters of this mode are strongly influenced by the generation. For g = 0 dendrimer, a narrow TSC relaxation mode, with a quasi-Debye behavior has been also found. It has been associated with dipolar relaxation of aldehyde groups. This mode is observed in g = 1 and g = 2 dendrimers, with a mild modification of its characteristics due to interactions with phosphorus/sulfur strong dipoles (P = S groups). An additional metastable mode has been experimentally isolated. It might be due to structural relaxation.