Synthesis Of Liquid Crystalline Polymers And Elastomers Containing Chiral Groups And Fluoronatied Units

Due to the advantages of fluorinated liquid crystals, such as low viscosity, high resistivity, good stability, suitable dielectric constant, rapid response and so on, fluorinated liquid crystalline materials become very important in the display field.It is fluorine's small size, large electronegativety, and large fluorine-fluorine repulsion that lead to many excellent properties of fluorinated liquid crystals. Based on the different positions of fluorine atoms or fluorinated groups in molecules, fluorinated liquid crystals are classified in three species: liquid crystals bearing fluorine atoms or fluorinated groups as terminal groups, liquid crystals containing benzene ring with hydrogen atoms substituted by fluorine atoms, and liquid crystals with central bridge bond having hydrogen atoms substituted by fluorine atoms. According to the difference of liquid crystalline system in which they are, the changes of position and number in molecules, fluorine atoms make fluorinated liquid crystals possess diverse properties. At the same time, side-chain and terminal fluorinated compounds can raise the solubility of other liquid crystals in mix LCs due to fluorine's greasy solubility. For these reasons, fluorinated liquid crystals provide a wide choice for the deployment of various high-performance mixed-LCDs.In this dissertation, six liquid crystalline monomers were synthesized, which include 4-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctanoyloxy) phenyl 4- (undec-10-enoyloxy) benzoate(M1),4-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctanoylperoxy)phenyl 4-(ally loxy)benzoate(M2),6-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctanoyloxy) hexa hydro furo[3,2-σ]furan-3-yl 4'-(undec-10-enoyloxy)biphenyl-4-ylterephthalate(M3), Hexahydrofuro [3,2-σ]furan-3,6-diylbis(4-(allyloxy)benzoate)(M4), Biphenyl-4,4'-diylbis(4-(allyloxy)ben zoate)(M5),cyclopenta[(?)]phenanthren-3-yl 4-(allyloxy)benzoate (M6). And then fluorinated monomers,2-(allyloxy)oxirane(M7), chiral monomers were grafted to linear polymethylhy drogensiloxanes. So four series of liquid crystalline polymers(LCPs) with different chemical structures and characters were synthesized.Polymers side-chain liquid crystalline elastomer were P1 and P2 series. Especially, fluorinated monomers and the four fluorinated side-chain liquid crystalline polymers were first prepared,they have important theoreticalvalue, and provides the development and application with technology support. The structures and properties of the obtained liquid crystalline monomers, crosslinking agent, LCPs and LCEs were investigated by FT-IR spectroscopy,1H-NMR spectroscopy, differential scanning calorimetry (DSC) and polarizing optical microscopy (POM), Their structure-property relationships were discussed in detail.In this dissertation, the structures of the three monomers and four series of LCPs were analyzed and proved.They have series of liquid crystalline texture. With increasing the concent of non-mesogenic crosslinking agent, Tg of P1 series and P2 series decreased firstly, and then increased; Tg of P3 series decreased in principle; Tg of P4 series increased on the whole. The four series of LCPs were liquid crystalline polymers. The effect of the content of crosslinking agent on phase behavior and thermal properties was discussed.