Highly ordered side-chain liquid-crystalline polymers from maleic anhydride and swallow-tailed 1-alkenes having two mesogens

Side-chain liquid-crystalline polymers (SCLCPs) were synthesized from the alternating copolymerization of maleic anhydride with swallow-tailed 1-alkenes having two mesogens. In contrast to similar polymers from 1-alkenes with one mesogen per repeating unit, these novel polymers exhibited lower isotropization temperatures and higher glass transition temperatures. The degree of order in the mesophase strongly increased: these SCLCPs exhibited a highly ordered smectic H phase. The polymers with a hexyl spacer between the malonate junction and the mesogen exhibited a uniaxially limited-correlation-length smectic E mesophase (SEu) which has, according to our knowledge, not been observed before. The highest transition temperatures and entropy changes were observed for polymers with completely interdigitated side chains.