The Main-Chain Liquid Crystalline Polymers With Pyridine Quaternary Ammonium Salts As Pendant Groups

Liquid Crystalline Ionomers?LCIs?have the characteristics of the liquid crystalline polymers and the ionic polymers.LCIs not only show properties of lyotropic liquid crystals and thermotropic liquid crystals,but also display some special properties such as electric conductivity,electrochromism,piezoelectric effect,light variability and so on.LCIs can dissolve in polar protic solvent and could be applied to many application area such as the engineering plastic,coating,membrane,separating membrane,polymer blend,composite,piezoelectric elasticity,ion exchanger and interfacial agent.As a kind of new functional polymer materials,liquid crystalline ionomers have the broad application prospect in the areas of physics,chemistry,materialogy,information,military,print,optical film materials,and so on.In this dissertation,two monomers were designed and synthesized including 4,4'-biphenyl bis?4-picolinate??M1?and cholesteryl 4-picolinate?M2?.One series of polymers?P1 series?were synthesized by a polycondensation reaction using 2,3-dibromosuccinyl dichloride,adipic acid and 1,6-hexanediol.Two series of LCIs?P2 series and P7 series?were synthesized by a polymerization reaction using P1 series of polymers,the monomers M1 and M2.The P3,P4,P5 and P6 series of LCIs were synthesized by a substitution reaction of hexafluorophosphoric acid,fluoroboric acid,trifluoroacetic acid,trifluoromethanesulfonic acid using P2 series of LCIs as mother polymers.Similarly,the P8,P9,P10 and P11 series of LCIs were prepared by a substitution reaction of hexafluorophosphoric acid,fluoroboric acid,trifluoroacetic acid,trifluoromethanesulfonic acid using P7 series of LCIs as mother polymers.Especially,these two series of quaternary ammonium salts and eight series of liquid crystalline polymers were first prepared.So the study in this dissertation was original.The structures and properties of the obtained liquid crystalline monomers,quaternary ammonium salts and LCPs were investigated by FT-IR spectroscopy,1H-NMR spectroscopy and ¹³C-NMR spectroscopy.The optical property of all the quaternary ammonium salts and LCIs were investigated by specific rotation analysis?SRA?.The thermal properties and mesogenic texture were studied with differential scanning calorimetry?DSC?and polarized optical microscopy?POM?analysis.In addition,the electrical performance of all the quaternary ammonium salts and LCIs were investigated by the conductivity meter.The experimental results showed that the chemical structures of all the synthesized monomers,all the quaternary ammonium salts and LCIs were consistent with the molecular design.Furthermore,all these materials showed good liquid crystalline behaviors and excellent electrical properties.The research in this dissertation not only has important theory and real meaning,but also can provide some theory basis and some necessary technical supports for further application of LCIs.