Abstract:

A novel conjugated polymer containing azobenzene and 1,3,4-oxadiazole units(LPOXD) was synthesized. The structure of the LPOXD was charactered by FT-IR, UV-Vis, 1H NMR, GPC, TGA and DSC. The results indicate that the intrinsic viscosity of the LPOXD is 0.02960 L/g, and its Mw and molecular mass distribution or polydispersity index(PDI) values are 8500 g/mol and 1.55, respectively. A 5% mass loss of the LPOXD occurred at 290 ℃. The glass-transition temperature(Tg) is 92.8 ℃. The introduction of long side chain of alkoxy significantly improved LPOXD′s solubility in common organic solvents such as chloroform, tetrahydrofuran, and so on. Furthermore, the optical and electrochemical properties of the LPOXD were investigated throughly by UV-Vis absorption spectroscopy, fluorescence emission spectroscopy and cyclic voltammetry. The results indicate that the azobenzene in the LPOXD involve a trans-cis photoisomerization under the radiation of 365 nm UV light. A wide fluorescence peak of the LPOXD appeared in the wavelength range of blue and purple light under excitaion at 350 nm. Cyclic voltammetry reveals that the LUMO and HOMO energies of the LPOXD are -5.96 eV and -3.17 eV, respectively.

Key words: azobenzene, oxadiazole, polymer, synthesis, properties