Electrosyntheses And Characterizations Of Two Novel Conducting Polymers Based On Polyfluorene

At present the conducting polymers research are focused on the preparation ofconducting polymers and their electrochromic properties. Electrochemicalpolymerization has been proved to be one of the most useful approaches forconducting polymer. Polyfluorenes (PFE) and their derivatives have drawn significantattention. The electrochemical polymerizations of fluorene derivaties with differentgroups on the backbone were discussed. Firstly, the electrochemical polymerization of9H-fluoren-9-ol was discussed. And then, we prepared a new compound(EDOT-MDOF) by synthesizing3,4-ethylenedioxythiophene(EDOT) with7,7’-(9,9-dioctyl-9H-fluorene-2,7-diyl)bis(2,3-dihydrothieno[3,4-b][1,4]dioxine)(MDOF) via Stille coupling reaction. Then a new polymer P(EDOT-MDOF) weresuccessfully prepared by electrochemical polymerization of EDOT-MDOF. Theelectrochromic properties of P(EDOT-MDOF) were also investigated.1. Electrochemical polymerization process of9H-fluoren-9-ol and thecharacterizations of its polymer were studied. Poly(9H-fluoren-9-ol) was obtained inacetonitrile (CAN) with15%trifluoroacetic acid (TFA) and0.1mol L-1TBATFBthrough electrochemical polymerization. The conductivity of this polymer is2.35×10-2S cm-1. In this system, the oxidation potential of9H-fluoren-9-ol is1.62Vvs SCE. The film of poly(9H-fluoren-9-ol) shows good redox activity and redoxstability.1H NMR and IR spectra showed the polymerization was occured in C-2andC-7positions. Thermal gravimetric analysis proved that the film had good thermalstability. Fluorescence spectra showed the polymer film was a good kind ofblue-emitting material. 2.Poly(7,7’-(9,9-dioctyl-9H-fluorene-2,7-diyl)bis(2,3-dihydrothieno[3,4-b][1,4]dioxine)) P(EDOT-MDOF), a novel electrochromic material obtained from3,4-ethylenedioxythiophene (EDOT)-bis-substituted monomer9,9-dioctyl-9H-fluorene via Stille coupling reaction in CH2Cl2solution. This conducting polymer hasgood redox activity and electrochromic performance. The polymer can change colorsbetween purple and blue. The coloration efficiency (CE) is was measured as42.88cm2C-1(at580nm), The response required to attain95%of total transmittancedifference was found to be1.45s at580nm from the oxidized to the reduced state,and the response time was2.59s at580nm from the reduced to the oxidized state.The ECD expressed good coloration efficiency and good response time. Theelectrochromic devices (ECD) was constructed with poly(3,4-ethylenedioxythiophene)(PEDOT). The response required to attain95%of total transmittance difference wasfound to be0.52s at616nm from the oxidized to the reduced state, and the responsetime was0.64s at616nm from the reduced to the oxidized state. The colorationefficiency of the ECD was measured as72.9cm2C-1(at616nm).