Synthesis And Characterization Of Amphiphilic Compounds

Series of amphiphilic liquid crystals have been synthesized and their properties were studied.2-（2-Methoxyethoxy）ethanol and 2-（2-（2-methoxyethoxy）ethoxy）-ethanol used as hydrophilic components were attached to 4-carbethoxyphenol, methyl 3,5-dihydroxybenzoate, methyl 3,4-dihydroxybenzoate and methyl gallate and then reduced with LiAlH4to prepare the hydrophilic units which contains 2 or 3 EO chains, MeO（EO）₂PCH₂OH, MeO（EO）₃PCH₂OH, m-[MeO（EO）₂]₂PCH₂OH, m-[MeO（EO）₃]₂PCH₂OH, o-[MeO（EO）₂]₂PCH₂OH, o-[MeO（EO）₃]₂PCH₂OH, [MeO（EO）₂]₃PCH₂OH, [MeO（EO）₃]₃PCH₂OH.The hydrophobic units were prepared by the reaction of C₁₂H₂sBr and methyl 3,5-dihydroxybenzoate and reduced by LiAlH4. The units reacted with the corresponding rigid units,4-hydroxybenzoic acid and 4’-Hydroxy-4-biphenyl-carboxylic acid to prepare the hydrophobic liquid crystal intermediates (C₁₂H₂₅O)₂PCH₂OPCOOH and (C,2H₂₅O)₂PCH₂OPPCOOH by the Mitsunobu reaction first and hydrolysis reaction sequentially.Target products were then prepared by esterification reactions of hydrophobic intermediates and hydrophilic units, with a total of two series,16 compounds.1. The purity and structures of the obtained compounds were investigated by HPLC,1H-NMR. All of the target compounds are meet the design of molecular structures, and the purity is at least 96%, partially 99%.2. Thermodynamic properties of molecules were investigated by DSC. In series 1, the melting point and clearing temperature of compounds were decreased along with the length and number increase of the EO chain, and the clearing temperature of compounds EO chain in meta substituent is lower than compounds EO chain in ortho substituent. In series 2, most of compounds have low melt temperature, which are difficult to crystallize.3. The textures of the target compounds were investigated by POM. In series 1, most of them showed liquid crystalline texture. In series 2, compounds m-[Me（OE）₂O]₂PCH₂OOCPOCH₂P(OC₁₂)₂ and o-[Me（OE）₂O]₂PCH₂OOCPOCH₂P(OC₁₂)₂ easy to crystallize, showed liquid crystalline texture.4. Emulsion of target compounds were prepared to study the behavior of self-assembly. All of target compounds self-assembled into hard or soft dendrimersomes, with the vesicle size among 1～60μm, investigated by POM and particulate size description analyser2（PSDA）.