Supramolecular organization of model liquid crystalline ionomers

A mesogenic cation was associated with low molecular weight carboxylato- and sulfonato(se-mi)telechelic polymers. These compounds were prepared by ion-exchange of the quaternary ammonium group attached to the mesogen for the metal counterion of the halato(semi)telechelic polymer. The accordingly formed liquid crystalline halato(semi)telechelic polymers (LC H(S)TP's) were analyzed by differential scanning calorimetry (DSC), polarized-light optical microscopy (POM), and small angle X-ray scattering (SAXS). On the basis of these experimental results, a model for the supramolecular organization of the LC H(S)TP's is proposed. The final morphology results from the interplay of two competitive effects: the dipolar interaction of the ion-pairs known for multiplet formation and the propensity of the mesogenic moiety to form mesophases. The outcome of this competition depends on the mobility of the mesogenic counterion, i.e., on the strength of the dipolar interactions, the mobility of the polymer backbone and the mesogen/poly-mer ratio which is controlled by the molecular weight of the polymer.