Synthesis And Characterization Of Liquid Crystalline Networks Containing Fluoronatied Units And Chiral Groups

The fluorinated liquid crystals own high resistivity, low viscosity, rapid response, due to the introduction of the atom of fluoride. Fluorined liquid crystal has broad application prospect. Chiral liquid crystalline polymers (LCPs) were also a hotspot of liquid crystalline research domains at present time. Due to the helical supermolecular structure, chiral liquid crystalline owns unique photo-electrical property.Besides the optical and orientation property of the liquid crystal, the liquid crystal elastomers (LCEs) also have excellent mechanical property and chemical stability of the network polymer. It has become a hot topic during the liquid crystal polymer research area. Therefore, study on cholesteric LCEs holds not only important theoretical purpose, but also potential applications in numerous areas, especially in the fields of piezoelectric materials and nonlinear optics etc.In this dissertation, eight monomers were synthesized. There are4-(4-(allyloxy)benzoylo-xy)phenyl-4-cyano-3-fluorophenyladipate(M1),4’-(4-(allyloxy)benzoy-4’-(4-(allyloxy)benzo-yloxy)biphenyl-4-yl-4-cyano-3-fluorophenyl-adipate(M2),4-cyano-3-fluorophenyl-4-(undec-10-enoyloxy)benzoate(M3),4’-(4-(allyloxy)benzoyloxy)biphenyl-4-yl-6-(2,2,3,3,4,-4,5,5,6,6,7,7,8,8,8-pentadecafluorooctanoyloxy)hexahydrofuro[3,2-b]furan-3-yl-adipate(M4),1-(4’-(4-(allyloxy)benzoyloxy)biphenyl-4-yl)10-(6-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafl-uorooctanoyloxy)hexahydrofuro[3,2-b]furan-3-yl)-decanedioate(M5),6-hydro-xyhexahydrofu-ro[3,2-b]furan-3-yl-4’-(4-(undec-10-enoyloxy)benzoyloxy)biphenyl-4-yl-adI-pate(M6),6-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctanoyloxy)hexahydrofu-ro[3,2-b]furan-3-yl-4’-(undec-10-enoyloxy)biphenyl-4-carboxylate(M7),4-cyano-3-fluoroph-enyl-4-(allyoxy)benzoate(M8). They were grafted to linear polymethylhydrogensiloxanes with crosslinking agent or AOO. Six series of liquid crystalline polymers (LCPs) with different chemical characters were synthesized. Liquid crystalline networks were N1-N2series. Polymers with side-chain liquid crystalline were P1-P4series. Especially, fluorinated monomers and the six series of liquid crystalline polymers were first prepared. The structures and properties of the obtained liquid crystalline monomers and LCPs were investigated by FT-IR spectroscopy,1H-NMR spectroscopy, all the monomers and six series of LCPs were analyzed and proved; differential scanning calorimetry (DSC) and polarizing optical microscopy (POM), Their structure-property relationships were discussed in detail.Besides M7and M8, all of them have series of liquid crystalline texture. The effect of the content of crosslinking agent or AOO on phase behavior and thermal properties of LCPs was discussed.Not only they have important theoreticalvalue, but also provide the development and application with technology support on piezoelectricity area.