Synthesis And Liquid Crystalline Properties Of Fan-shaped Chiral Ionic Liquid Crystals

3,4,5-Tris?alkoxy?benzyl salts are fan-shaped onium structures consisting of ionophobic and ionophilic parts.They can self-assemble into thermotropic 2D columnar phase or 3D cubic liquid crystalline phase.The bicontinuous channel structures of Cub_bi LC materials provide them with potential applications in nanofiltration membranes and drug delivery systems.Introduction of chiral carbon in LC molecules is tend to break mirror symmetry of liquid crystalline phase structure.Chiral conglomerate formation might induce the helical arrangement direction,inlarge the chirality and construct chiral liquid crystalline phase.In this thesis,chiral carbon was introduced in anion or cation part of 3,4,5-Tris?alkoxy?benzyl salts.Such chiral fan-shaped ionic liquid crystals were synthesized,their phase transition during changing temperature and chirality synchronization in LC phases were investigated.The main contents are as follows:In the first part,AB₃-type ammonium salts 1-6 with chiral anion part were synthesized.Three chiral amino acids were used as anion part of ammonium salts.The cation part was trimethyl-or triethyl-ammonium salts and—C₈H₁₇,—C₁₀H₂₁ or—C₁₂H₂₅ were chosen as the ionophobic chains.Through DSC,POM,SAXS and GISAXS experiments,it was indicated that compounds 1 and 2 containing N-methyl-L?or D?-alanine show Ia3d Cub_bi phases,and compounds 3-6 containing L?or D?-alanine or L?or D?-cysteine show columnar phases.The number of molecules contained in different molecular cells and each unit cell was calculated.The columnar phase and the three-dimensional Ia3d phase may be applied to ion channels and electron distribution.The chiral anion-comprising compounds accord with the dv?dr radial distribution curve,that is,the mesogen phase state of the fan-shaped molecule is affected by the shape of the molecule,which is consistent with the regularity of the smectic phase—cubic phase—column phase transition?when P is from 0 to 1?.CD experiments confirmed that molecules are chiral in arrange of liquid crystalline phases.Further,the enantiomeric 1:1 mixture showed that the chirality not only affects the phase transition point of the compound,but also affects its liquid crystal behavior.Although no new phase occurs,the phase behavior is different in the original temperature range.In the second part,AB₃-type ammonium salt 13 with chiral cation part was synthesized.In compound BzAA*⁺BF^4-,AB₃ part and ammonium salt was linked by chiral carbon ester.Through DSC,SAXS and GISAXS experiments,it was indicated that compound 13 show a new liquid crystalline phases,which have 10 XRD peaks and belong to 3D phases.The self-assembly structures of the new phase is still under investigation.It was found that compound 13 is unstable at higher temperatures and degrade over a long period of time under ultraviolet irradiation?this process is irreversible?.The new phase helps us understand the relationship between LC molecules and LC phase structures and the influence of introduction of chiral carbon into the LC molecules.