Synthesis And Electrochromic Studies Of Polyesters And Polyamides

Electrochromism(EC)can be defined as a reversible change in the transmittance and color reflectance of a material by applying different voltages with the result of electrochemical oxidation or reduction.Electrochromic materials are a kind of materials whose application range is very wide in the glare-free mirror,smart windows,information storage,electrochromic devices and other fields.In this study,we design a series of polyaimides(PAs)and poly(ester)s(PET)containing triphenylamine(TPA)with electrochromic properties.There are 18 species of PAs and 5 species of PETs.TPA and its derivatives group,which not only have good ability of hole-transport,but also have excellent performance of EC.So this paper is based on TPA block.The PAs exhibited good solubility in many organic solvents and displayed outstanding thermal stability.These PAs exhibited green fluorescence in dimethyl sulfoxide(DMSO)solution.The highest occupied molecular orbital(HOMO)and lowest unoccupied molecular orbital(LUMO)energy levels of these PAs were calculated to be from-1.12 e V to-2.67 e V and-5.18 to-3.88 e V respectively.The PAs films not only generated photovoltagic and photocurrent under simulated solar radiation,but also had good electrochromic.PETs were prepared based on N,N'-two(?-naphthyl)-N,N'-dicarboxy para-phenylene diamine and a series of dihydroxy compound.The PET had excellent solubility in majority organic solvents.The aromatic PET exhibited photoluminescence(PL)emission maxima bands around490-540 nm in DMSO solution.Most of them exhibited light yellow in original state,but the colour changed from light yellow to red in oxidized state upon increasing voltage.The LUMO and HOMO energy levels of these PET were calculated to be from-1.98 to-1.51 e V and-5.24 to-5.18 e V respectively.In addition,PET generated photocurrent and photovoltagic under simulated solar radiation,which are promising materials in photovoltaic devices and display.In this study,all polymers were characterized by FT-IR spectroscopy,¹H NMR,¹³C NMR,TGA,SEM and X-ray diffraction patterns.The photoelectric stability and electrochromic properties of these polymer materials were tested by photocurrent,photovoltage,UV–vis spectra,PL spectra and CV measurement.The above results prove that aromatic PAs and PETs in this paper are multifunctional materials,and can be used as important candidates for chemical sensor,hole-transporting,electrochromic application in near future.