Molecular dynamics of smectic liquid crystalline side-chain polymers as studied by dielectric relaxation spectroscopy

The dielectric properties of the liquid crystallline polymethacylates with side chain containing a terminal alkyloxy chain have been over wide ranges of frequency and temperature. The temperatures corresponding to the peak of the dielectric loss tangent for PM6BP and PM6BP5 in its temperature dependence agreed well with those phase transition. The activation energies at low temperature agreed with delta-relaxation which is epsilon(sic)-relaxation by rotation of mesogenic group around the backbone chain. The dipole moment have been calculated by using the Frohlich modification of Onsager's equation. The alignment of both materials in the present of an a.c.electric field are also discussed.