| Fluorinated compounds including fluoropolymers have attracted wide interest in the fundamental material sciences and applied technologies for past fifty years, since the fluorinated surface is effective on the tribological behavior due to the low energy surface and negative surface potentials besides their excellent thermal stability and chemical resistance.It is fluorine's small size, large electronegativity,low polarizability,and large fluorine-fluorine repulsion that lead to many interesting properties of fluoropolymers.Side-chain and terminal fluorinated compounds can raise the solubility of other liquid crystals(LCs) in mix LCs due to fluorine's greasy solubility.In this dissertation, seven monomers were synthesized. Different kinds of mesogenic monomers (including nematic monomers and cholesteric monomers) were grafted to linear polymethylhydrogensiloxanes. So four series of liquid crystalline polymers(LCPs) with different chemical structures and characters were synthesized.The structures and properties of the obtained liquid crystalline monomers and polymers were investigated by FT-IR spectroscopy, differential scanning calorimetry (DSC), polarizing optical microscopy (POM), specific rotation analysis (SRA),1H nuclear magnetic resonance (1HNMR) and X-ray analysis.Four fluorinated monomers are synthesized by 4-fluoro-benzoic acid, two of which are nematic liquid crystallines during heating and cooling processes. One is LC bearing trifluorinated group synthesized by m-trifluomethylphenol. One monomer, not bearing fluorinated group, has excellent LC qualities due to well matching of firm chain and soft chain.One monomer, as second important monomer in polymers, is cholesteric LC monomer.Polymers P1, P2, P3 were liquid crystals changing from smectic phase to cholesteric phase during heating process, polymers P4 were nematic liquid crystals. |
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