Broadband dielectric spectroscopy on ferroelectric liquid crystalline polymers

The collective and molecular dynamics of ferroelectric liquid crystalline side group polysiloxanes has been investigated for use of broadband dielectric spectroscopy (10-2 Hz - 109 Hz). In the lower frequency range (< 106 Hz) two collective relaxations, Goldstone- and soft-mode, could be observed. They are assigned to the fluctuations of the phase and the amplitude of the helical superstructure, respectively. In the high frequency regime (106 Hz - 109 Hz) one dielectric relaxation, the (beta) - relaxation, is found. It is assigned to the hindered rotation (libration) of the mesogene around its long molecular axis. It shows an Arrhenius-like temperature dependence with no deviations at the phase transition SA/S*C. A dilution of the mesogenes causes a decrease of the collectivity but remains the local dynamics uninfluenced.