Mesomorphic and dielectric properties of a side-chain liquid crystalline polyacrylate and copper(II) crosslinked derivatives

Abstract

A side-chain liquid crystalline polyacrylate containing a salicylaldimine group has been synthesized and complexed with copper(II) ions to generate metallomesogenic crosslinking of polymeric chains. The mesomorphic properties of the parent and complexed polymers have been studied by optical microscopy, DSC and X-ray diffraction. In addition, these materials have been investigated in depth by dielectric spectroscopy. Dielectric measurements of the parent polymer reveal the presence of two sub-glass relaxations (β and γ). The α relaxation associated with the T_g is masked by a conductive process, but at higher temperatures a δ relaxation is observed. These relaxation processes have been characterized and their activation energies evaluated. The influence of the mesogenic order and metal crosslinking on some relaxation processes has also been determined.