Design, Synthesis And Characterization Of A New Type Of Electrochromic Near-UV Light-emitting Materials

The introduction of the proper substitute group into the backbone of the conjugated polymer can not only increase the solubility, but also the stereoscopic and electronic effect will affect the conjugated planes of the polymer, and the energy band will change, this is the substitute group modification in the conjugated polymer energy band engineering. Based on this,a single benzene polymer and bi-benzene polymer with different substitute group density has been designed and synthesized through Suzuki metal coupling reaction, in order to prepare the electro-near ultraviolet-emitting material. The structures and properties of monomers were identified by using elementary analysis, IR and NMR. The polymers are gray powder solid and soluble in common organic solvents such as Chloroform and THF at room temperature.The effects of the different length of end alkoxy group and difference of dipolar units on polymer structure of the main chain regularity, liquid crystal and the optical propertie were investigated by NMR, GPC, Polarizing microscope with heat stage, UV-vis spectra and photoluminescence excitation and emission spectra. It is found that the added of the alkoxy group can improve the polymer structure of the main chain regularity, increase the solubility of polymer and raise the fluorescence quantum efficiency of solution. The maximum emission of the spinning film of P1 is at 400nm, which is at 410 nm of P2 and 416 nm of P3. This indicates increase the density of side groups can distort the main chain, weaken the conjugation, make blue-shift of emission peak. In addition, the ester linkages of P3 compared to the ether bonds of P1 and P2, heated in the liquid crystalline state, the maximum fluorescence emission peak of the polymer shifted to 393 nm, This shows that the optical properties of polymer P3 has a great relationship with its thermal history.Finally, by virtue of spontaneous orientation of liquid crystalline side chains under external force, the orientation ability of the polymers have studied through the commercialized PA orientation board. Through the comparsion of the FL spectrum of the orientation film of P1, P2 and P3, we found that the orientation of the dipole unit affects orientation of the backbone of the polymer a lot, the increase in density of the side group is good for the orientation of the main chain of the polymer.