A new series of two-arm (MB1, MB2), four-arm (MB3), six-arm (MB4) chiral liquid crystalline compound containing isosorbide as chiral core were first synthesized. Four precursors of branched-arm B1~B4 were obtained at first and then were esterized separately with isosorbide and got four chiral branched-arm liquid crystals (MB1~MB4). The chemical structures and LC properties of the liquid crystalline molecule were measured by spectrum and thermal analysis techniques. XRD curves of MB1~MB4 samples only showed broad peaks at wide-angle, but no sharp peak was seen for all the samples. The results showed that MB1~MB4 appeared cholesteric phase with oily streak texture or lined texture and finger print texture. Isosorbide successfully induced cholesteric phase. The values of melting point and clearing point for MB1~MB4 decreased. The quantity of branched-arm and chiral core had effects on their liquid crystalline properties.
In the present work, a ester of glucose (a) with 4-(4-(ethoxybenzoyloxy) phenoxy) -6-oxohexanoic acid side–arms has been synthesized. Compared withbandc, reported previously,ahad the same side-arms but different chiral core. The phase behaviors of three star-shaped liquid crystals (a, b, c) have been compared and studied, and the effect of the different structure of chiral core on the phase behaviors of the star-shaped liquid crystals has been discussed. a, b andcdisplayed cholesteric phase, unlike the nematic side arm.a, b andcwere all laevo-rotationary, unlike their parent cores. The melting temperature of a, b andcdecreased with the increase of the sugar ring of the chiral core. The mesomorphic region ofaon cooling cycle was wider than that on heating cycle. Forbandc, the case was similar.
A series of new chiral side-chain liquid crystalline polymers with electron donor-acceptor action were prepared containing chiral monomer with donor group and nematic LC monomer with acceptor group. All polymers were synthesized by graft polymerization using polymethylhydro- siloxane as backbone. The mesomorphic properties were investigated by differential scanning calorimetry(DSC), polarizing optical microscopy(POM),thermogravimetric analyses(TGA) and X-ray diffraction measurements(XRD). The chemical structures of monomers and polymers were confirmed by Fourier transform infrared (FTIR), proton nuclear magnetic resonance spectra(1H NMR and 13CNMR). M1 showed nematic phase and M2 turned out cholesteric phase on heating and cooling cycle. Polymers P3~P8 were cholesteric phase. Experimental results demonstrated that the glass transition temperatures and isotropization temperatures and the ranges of the mesophase temperature increased with increasing the content of chiral agent. All of the obtained polymers showed high thermal stability.
The synthesis of new chiral monomer 4-((4-(allyloxy) benzoyl) oxy) phenyl (S)-4-(2-methylbutoxy) benzoate (Mch), crosslinking agent hexane-1,6-diyl diacrylate (CA), and liquid crystal polymer elastomers (E1-E7) containing (S)-(-)-2-Methyl-1-butyl group is presented. The phase behavior and mesomorphism of the polymers were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and x-ray diffraction. The effect of the content of crosslinking units on the phase behavior and mesomorphism of elastomers was discussed. The chiral LCEs (E1-E7) exhibited elasticity, reversible phase transitions, and cholesteric Grandjean texture. The experimental results demonstrated that the glass transition temperature and isotropic temperature of Chiral LCEs decreased with increasing the content of crosslinking agent, but the cholesteric phase was not disturbed.
A series of main-chain liquid-crystalline polymers containing maltose were synthesized by interfacial condensation reactions of sebacyl chloride, 4,4’-Dihydroxy-2,2’-dimethyl Benzalazine(DDBA), and 1-O-[4´-O-(α-D-glucopyranosyl)-ß-D-glucopyranosyl]-methanol(MM). The effects of MM on characteristics of liquid-crystalline properties were studied. P1- P3 exhibited nematic mesophase on heating and cooling cycle, while P4- P7 exhibited both chiral smectic A and nematic mesophases on heating cycle and nematic mesophase on cooling cycle. P8 did not exhibit any mesophase on heating and cooling cycle. The glass-transition temperature decreased with increasing concentration of MM.
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