PARAMAGNETIC LIQUID-CRYSTAL SIDE-CHAIN POLYACRYLATES CONTAINING SCHIFF-BASE COPPER(II) COMPLEXES

Polymers containing Schiff base copper complexes were synthesized from thermotropic liquid-crystalline polyacrylates containing a mesogenic bidentate Schiff base as the side cain. The introduction of the copper atoms (5-65 mol%), gave rise to cross-linked polymeric chains, and th e copper content of the polymers was determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The liquid-crystal pro perties were examined by differential scanning calorimetry (DSC), pola rizing microscopy and electron paramagnetic resonance (EPR) spectrosco py. The mesophases of the original polyacrylate are enantiotropic smec tic A and smectic C, whereas polymers containing the bis(Schiff base)c opper(II) complex in different proportions exhibit an enantiotropic sm ectic C mesophase. The EPR measurements of this type of copper-coordin ated polymer at different temperatures indicate a restricted motion of the copper complex around the long molecular axis and provided inform ation on the local order of the molecules in the liquid-crystal phase.