Local modes of molecular mobility in comb-shaped liquid crystalline ionomers containing alkaline metal ions

Molecular mobility of the comb-shaped copolymer poly(4-[6-(acryloyloxy)hexyloxy]benzoic acid-co-butyl acrylate) and Li- and Rb-containing LC ionomers based on this polymer was studied at low temperatures by the methods of dielectric spectroscopy and thermally stimulated depolarization current. The above copolymers are shown to experience the γ2, γ1, and β-processes, which are related by the reorientation of the end СООН groups, by the mobility of a spacer, and by the reorientation of mesogenic fragments (dimers of oxybenzoic acids) with respect to a long axis, respectively. The formation of multiplet structures in ionomers leads to a suppression of the intensity of the β-process that relates with a partial breakdown of hydrogen-bonded dimmers and with a decrease of their molecular mobility.