Study On The Synthesis And Electrochromism Of Poly Schiff Bases Containing Triphenylamine Groups

Electrochromism(EC)can be defined as a stable and reversible change under the influence of the applied electric field,and displayed a reversible change of color and transmittance in appearance.Therefore,the EC materials have been widely used in many fields,such as smart windows,display devices and electrochromic devices.Moreover,Organic EC materials have attracted widely attention of researchers and become a research hot spot due to its fast response,color varied,low cost and easy to synthesized.In this paper,we used N-(4-aminophenyl)-N-(p-tolyl)benzene-1,4-dialdehyde,N,N'diphenyl-N,N'-bis(4-anilino)terephthalic dialdehyde,N,N'diphenyl-N,N'-bis(4-aniline)biphenyl dialdehyde,N,N'-bis(?-naphthyl)-N,N'-bis(4-anilino)terephthalic dialdehyde and N,N'-bis(?-naphthyl)-N,N'-bis(4-aniline)biphenyl dialdehyde as monomer,then synthesized a series of poly Schiff bases(PSBs)containing triphenylamine with four different diamines by polycondensation method.The structures of the polymers were investigated by Iinfrared Spectroscopy spectroscopy(FT-IR)and 1H NMR;the thermostability and morphology wereas studied by thermogravimetric analysis(TGA);the molecular weight was measured by gel permeation chromatography(GPC);the optical performance were measured by ultraviolet and fluorescent;the acidichromism was measured by ultraviolet and the energy of the molecular was calculate by Gaussian 98 program.The PSBs own excellent solubility in many organic solvents,so the polymer solution can be spin-coated on ITO glasses,and then studied the EC properties by absorption spectra(UV-vis)and cyclic voltammetry(CV)method.With the increase of voltage,the color of PSB films changed from yellow to blue,and were stabilized after repeatedly cycles,which proved the polymers own good film-forming property and redox reversibility.Moreover,the polymers own outstanding thermal stability with decomposition temperature is about 280~oC,and 10%loss-weight is about 400~oC,when the temperature raise to 700 ~oC,the residue is more than 60%.The PSBs showed blue-green fluorescence in dichloromethane.And the PSBs had acidichromism properties,and their color changed from yellow to red or colorless to yellow.Furthermore,it also generated photovoltagic and photocurrent under simulated solar radiation.And the change of gaps of energy band(analyzed by the electrochemical performance)were conformity with that theoretical calculated by computer.Based on the above performances,the PSBs,which are synthesized in this paper,have provide the new products for eletrochromic and acidichromism materials,and can applied in many field,such as chemical sensors,hole transport and display devices.