| 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. Due to the advantages of fluorinated liquid crystals, such as low viscosity, high resistivity, rapid response, increasing dielectric constant and so on, Fluorined liquid crystal has broad application prospect. 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 LCDs 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, nine liquid crystalline monomers were synthesized, which include4-cyano-3-fluorophenyl-4’-(undec-10-enoyloxy) biphenyl-4-carboxylate(M1),4-cyano-3-fl-uorophenyl-4’-(allyloxy)biphenyl-4-carboxylate(M2),4-(undec-10-enoyloxy)phenyl-4’-(allyl-oxy)biphenyl-4-carboxylate(M3),4-(4-(undec-10-enoyloxy)benzoyloxy)phenyl-4’-(allyloxy)-biphenyl-4-carboxylate(M4),6-(4-(allyloxy)benzoyloxy)hexahydrofuro[3,2-b]furan-3-yl-4’-(u ndec-10-enoyloxy)biphenyl-4-carboxylate(M5),4’-(undec-10-enoyloxy)biphenyl-4-yl-4’-(ally-loxy)biphenyl-4-carboxylate(M6),6-(undec-10-enoyloxy)hexahydrofuro[3,2-b]furan-3-yl-4’-(undec-10-enoyloxy)biphenyl-4-carboxylate(M7),6-(undec-10-enoyloxy)hexahydrofuro[3,2-b]furan-3-yl-4’-(allyloxy)biphenyl-4-carboxylate(M8),6-(4-(allyloxy)benzoyloxy)hexahydrof-uro[3,2-b]furan-3-yl-4’-(allyloxy)biphenyl-4-carboxylate(M9). So seven series of liquid crystalline polymers(LCPs) and liquid crystal elastomers (LCEs) with different chemical structures and characters were synthesized. Especially, fluorinated monomers and the seven fluorinated side-chain liquid crystalline polymers and liquid crystal elastomers were first prepared.The structures and properties of the obtained liquid crystalline monomers, crosslinking agent, LCPs and LCEs were investigated by FT-IR spectroscopy,’H-NMR spectroscopy, differential scanning calorimetry (DSC)and polarizing optical microscopy (POM), Their structure-property relationships were discussed in detail.Not only they have important theoreticalvalue, but also provide the development and application with technology support on piezoelectricity area. |
