Synthesis Of Main-Chain Liquid Crystalline Ionomers Containing Pendant Imidazolium Groups

Liquid crystalline ionomers?LCIs?are the kinds of polymers which contain ions and show liquid crystalline behaviors.Main chain liquid crystalline ionomers?MCLCIs?are LCIs bearing both mesogens and ions on the main chain.In recent reports,some groups such as sulfonic acid groups,carboxyl and ammonium groups etc are mainly used as ionic groups for MCLCIs.Some MCLCIs containing pendant imidazolium groups were synthesized in this dissertation.Four monomers were designed and synthesized in this dissertation including decanedioyldichloride?M₁?,4,4'-?decanedioylbisoxy?dibenzoic acid?M₂?,2,3-dibromosuccin-yl dichloride?M₃?,4,4'-?decanedioylbisoxy?bis?2-fluorobenzoic acid??M₄?.A series of liquid crystal polymers?P₁?was synthesized by a polycondensation reaction using M₁,M₃ and 1,6-hexanediol?E₁?.The series of MCLCIs?P₂?were obtained by a quaternization reaction using N-methylimidazole and the P₁ samples.And then the P₂ series reacted with tetrafluoroborate solution,hexafluoro phosphoric acid,trifluoroacetic acid,trifluoromethane sulfonic acid to obtain the series of MCLCIs?P₃-P₆?.A series of liquid crystal polymers?P₇?was synthesized by a polycondensation reaction using M₂,M₃ and 4,4'-biphenol?E₂?.The series of MCLCIs?P₈?were obtained by a quaternization reaction using N-methylimidazole and the P₇ polymers.The series of MCLCIs?P₉-P₁2?were synthesized by use of tetrafluoroborate solution,hexafluoro phosphoric acid,trifluoroacetic acid,trifluoromethanesulfonic acid and P₈ ionomers in an anion exchange reaction.The series of liquid crystal polymers?P₁3?was synthesized by a polycondensation reaction using M₃,M₄ and E₂.The series of MCLCIs?P₁4?were obtained by a quaternization reaction using N-methylimidazole and the P₁3 polymers.The series of MCLCIs?P₁5?were synthesized by use of trifluoroacetic acid solution and P₁4 ionomers in an anion exchange reaction.All these 15 series of polymers have not been reported in previous literature,thus the study in this dissertation is original.The chemical structures of liquid crystalline monomers were characterized by FT-IR and 1^H-NMR.The thermal properties and liquid crystalline behaviors of all the monomers and LCIs were characterized by differential scanning calorimetry?DSC?and polarizing optical microscopy?POM?.Experimental results show that the chemical structures of the synthesized monomer,polymers and LCIs conform to the molecular design.The research in this dissertation has important theory and real meaning.Moreover,it can provide some theory basis and some necessary technical supports for further application of LCIs.