Synthesis And Characterization Of A Series Of Star-like Compounds And Chiral Liquid Crystals

In recent year, chiral liquid crystalline (LC) polymers have attracted more and more attention, and they not only have the unique optical-electrical property but also the potential application in the fields of nonlinear optics, fast light switch, microelectronics. The synthesis of chiral LC materials with new structure has been an important subject in LC research. The liquid crystals which import in the fluorin atom who has small volume, high resistivity and low viscosity have the advantages as follows, good intermediate phase behavior, low viscosity, higher resistivity, higher polarity, higher stability and quicker response speed. So the application of liquid crystals which contains fluorin atom is more extensive.As a new type of liquid crystals, star-like liquid crystalline is playing an important role in display materials, organic conductor materials and nonlinear optics fields, due to their special structure and functionality. Glucose exhibit a good property of optical rotation, and also has many hydroxyl groups which are very active. Different-Arm star-like liquid crystalline macromolecules, with glucose as the core and side LC arms and non-LC arms introduced into the hydroxyls of the glucose, by through adjusting side arms structure and different proportion and get the synthesis of the low melting point and liquid crystal domain is broad, were synthesized. These researchs expanded the the types of the LC compounds and can also establish foundations for the application study of new types of LC compounds.In this dissertation, eight liquid crystalline monomers were synthesized, which include6-(4-(4-ethoxybenzoyloxy)phenoxy)-6-oxodecanoic acid (M),6-(4-(4-ethoxybenzoyloxy) phenoxy)-4-oxodecanoic acid (M2),4-(undec-10-enoyloxy)phenyl4-ethoxybenzoate (M3),6-(4-(4-methoxybenzoyloxy)phenoxy)-6-oxohexanoic acid (M4),6-(4’-cyanobiphenyl-4-yloxy)-6-oxohexanoic acid (M5),4’-cyanobiphenyl-4-ylundec-10-enoate (M6),4-Trifluoromethyl-benzoic acid4’-hydroxy-biphenyl-4-ylester (M7), Decanedioic acid-10-cyano-10-cholesteryl ester (M8). The star-like compounds (PG series) ware prepared by graft polymerization with reacting Mi, capric acid and glucose. The copolymers (P1and P2series) were prepared by graft polymerization with reacting monomers M6, M7, Ms and PMHS, respectively. There were no reported at home and abroad about monomers M3, M7, M8and Chiral side chain liquid crystal polymers (P1and P2series). So it’s creative in molecular design method.The structures and properties of the obtained liquid crystalline monomers and LCPs were investigated by FT-IR spectroscopy, XRD, differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). Their structure-property relationships were discussed in detail. The optical rotation of monomer Mg, P1and P2series was tested by the Model341Polarimeter of American PE company.The rotatory analysis shows that monomer Mg and side chain LCD polymer P1, P2series are levorotatory optical active substances.Eight kinds of monomer and three series LCD polymers all meet the molecular design and present some liquid crystal texture. The four monomers M1, M2, M4, M5present droplet texture and schlieren texture. The monomer M3present schlieren texture and threaded texture. The monomer M6present threaded texture. So the monomers M1-M6are nematic liquid crystals. The monomer M7present lined texture, rodlike texture and focal conic texture. So monomer M7is smectic liquid crystal. The monomer Mg present blue phase texture and Grand-jean texture. So monomer Mg is cholesteric liquid crystal. The polymer P1-7presents oily streak texture and focal conic texture. The rest of the two series side chain LCD polymers Pi, P2present Grand-jean texture. So they are all cholesteric liquid crystals. With the increase of the content of Mg, the Tg of P1series are decreasing gradually and the Ti of P1series are decreasing gradually and then increasing later. With the increase of the content of M%, the Tg of P2series don’t change significantly and the Ti, of P2series are decreasing gradually and then increasing later.