Redox active LC ionomers: LC ionomers as materials for compatible blends with amorphous ionomers

Abstract

AbstractRedoxactive liquid crystalline (LC) side group polymers were prepared by copolymerization of liquid crystalline acrylates and ferrocene‐containing acrylates. The corresponding liquid crystalline ionomers were synthesized by a reversible redox reaction. The incorporation of tetra‐alkylated ferrocene derivatives leads to LC polymers with reduced redox potential. These polymers can be oxidized under mild conditions to the corresponding ionomers, which are much more stable in solution than LC ionomers containing monoalkylated ferrocenium ions. Dynamic mechanical measurements and small angle X‐ray scattering (SAXS) perfomed on LC ionomers prove the existence of ionic superstructures (clusters) which are typical for ionomers and a gelation of the LC ionomers.In biphasic polymer blends consisting of liquid crystalline and amorphous ionomers (partially sulfonated polystyrene) we investigated the influence of the concentration of ionic groups in the LC component on the size of phase separated regions. It was found that blends without ionic interactions are macroscopically phase separated. In blends consisting of two ionic components, microphase separated regions of approximately 100 nm were found. The size of phase separated regions decreases continuously with increasing concentration of ionic groups in the LC component and can therefore be adjusted by a reversible redox reaction.The incorporation of ionic groups in LC polymers leads on a macroscopic scale to a combination of the liquid crystalline properties of the LC component with the elastic behavior of the amorphous ionomer. Therefore microphase separated ionomer blends show homogeneous liquid crystalline textures and behave mechanically like reversible crosslinked ionomers.