| A series of side chain liquid crystalline polyacetylenes with different lengths of spacers and different length of alkoxy tail were synthesized by Williamson etherification, esterification, Sonogashira reaction. The phase transition and phase structure, optical properties of the synthesized samples were investigated. The main content include three parts:1. Diphenylacetylene rod-like mesogens containing side chain liquid crystalline polyacetylenes with different length of alkoxy tails and different length of spacer were synthesized. The chemical structures were characterized by 1H NMR, 13 C NMR, and FTIR. TGA, DSC, POM, UV-vis, and PL were applied to characterize the thermal stability, liquid crystallinity, and optical properties. The results show that this series of samples can form liquid crystal phase. Upon excitation at 315 nm,strong blue emission peaks at 390 nm were observed. The quantum yield of monomer efficiency 61.8%;2. Methyl gallate and diphenylacetylene rod-like mesogens combine to form a Hemiphasmidic mesogens containing side chain liquid crystalline polyacetylenes monomer with different length of alkoxy tails and different length of spacer were synthesized. Through the characterization, the series of compounds also has a liquid crystal and luminescence;3. Liquid crystal phase structure and phase transition were studied by DSC,POM, Variable temperature one-dimensional and two-dimensional wide-angle X-ray diffraction(1D\2D-WAXD). Research on a series of different length spacer of biphenyl containing side chain liquid crystalline polyacetylene [P-m,7(m=3,4,5,8,9), P-m,5(m=3,9) and P-m,5L(m=3,9),m is the number of methylene] phase structure. The results show that the samples with different spacer length form liquid phase from highly ordered smectic phase to smectic B phase and the main chain and side chain appear decoupling effect at space length of 5 methylene units. |
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