The Supramolecular Liquid Crystal Based On Polyacrylic Acid And Imidazole Surfactants And Its Fluorescent Properties

In this thesis,two kinds of luminescent liquid crystal polymers with polyacrylic acid(abbreviated as PAA)as the main chain and imidazole surfactant as the side chain were constructed by hydrogen bonding,and their photophysical properties and stimulus response behavior were investigated respectively.The main research contents and conclusions are as follows:1、Imidazole surfactant containing biphenyl group(abbreviated as CBph CM)was synthesized from 4,4’-dihydroxybiphenyl,bromododecane,1,10-dibromodecane and imidazole,and its structure was characterized by ~1H-NMR,MS and FT-IR.Using PAA as donor material and CBph CM as acceptor material,liquid crystal polymer PAA-CBph CM was constructed by hydrogen bonding,and PAA-CBph CM was characterized by fourier transform infrared(FT-IR),thermogravimetry(TGA),differential scanning calorimetry(DSC),polarizing microscope(POM),X-ray diffractometer(XRD)and fluorescence(FL).The results show that PAA-CBph CM has good thermal stability,and can exist stably at a temperature less than 239℃,with a freezing point of 83.65℃and a melting point of 95.29℃.POM observed the texture of PAA-CBph CM focal cone,and the liquid crystal range was 161～83℃.XRD test further confirmed that PAA-CBph CM was the standard layered structure.FL test shows that CBph CM and PAA-CBph CM have fluorescence properties.When the excitation wavelength is 480 nm,a fluorescence peak is observed at 527 nm,and the fluorescence intensity of PAA-CBph CM is higher than that of CBph CM..2、Imidazole surfactant with azobenzene group(abbreviated as Azo CM)at the end group was prepared from 1,10-dibromodecane,hydroxyl azobenzene and imidazole,and its structure was characterized by ~1H-NMR and FT-IR.Using PAA as donor material and Azo CM as acceptor material,liquid crystal polymer PAA-Azo CM was constructed by hydrogen bonding,and fourier transform infrared(FT-IR),thermogravimetry(TGA),differential scanning calorimetry(DSC),polarizing microscope(POM),X-ray diffractometer(XRD),fluorescence(FL)and ultraviolet-visible light(UV-Vis)were used.The results show that PAA-Azo CM has good thermal stability and can exist stably before 220℃.During the cooling process,the liquid phase of PAA-Azo CM changed to liquid phase at 95.2℃,and the liquid phase changed to solid phase at 71.76℃,and the rod-like liquid crystal texture was observed by POM.FL test shows that Azo CM and PAA-Azo CM have fluorescence properties.When the excitation wavelength is 420nm,fluorescence peaks are observed at 466 nm and 634 nm,and the fluorescence intensity of PAA-Azo CM is higher than that of Azo CM.UV test shows that Azo CM can complete the transformation from trans isomer to cis isomer within 280 s under ultraviolet irradiation.Visible light irradiation can change from cis isomer to trans within 585 s.Under ultraviolet irradiation,the response time of PAA-Azo CM from trans isomer to cis isomer is 760 s,while that from cis isomer to trans isomer is 1920 s.