Preparation Of Novel Conducting Polymers Based On EDOT With Dibromide And Investations Of The Electrochromic Properties

Conducting polymers have attracted more attention due to some unique properties,including simple synthesis process,excellent processing performance,multicoloured properties.At present,the research of conducting polymers has mainly focused on the design and synthesis of new polymer monomer.3,4-ethylenedioxythiophene(EDOT)was widely introduced into the new monomer due to its unique performance.The corresponding electrochromic performance s of these polymers were also studied.Three novel monomers were synthesized by Stille coupling reaction,which were obtained from 5,7-dibromoindole and 2,7-dibromo-9,9 spirobifluorene,4,7-bis(2-bromo-5 Thiophenyl)-2,1,3-benzothiadiazole.The electrochromic properties of corresponding conducting polymer and electrochromic device were also studied.1.Poly(5,7-bis(2-(3,4-ethylenedioxy)thienyl)-indole)(PETI)was electrochemically obtained from 5,7-bis(2-(3,4-ethylenedioxy)thienyl)-indole(ETI),which was prepared by Stille coupling reaction of 5,7-dibromoindole and EDO T.The polymer film showed good electrochemical activity and reversible redox stability.The possible polymerization site of the polymer was investigated by FT-IR spectroscopy,1H NMR spectroscopy.Spectroelectrochemistry studies have shown that the polymer had excellent electrochromic properties and showed two different colors: brown and dark blue.And the polymers had good optical contrast(?T %),high coloring efficiency.An electrochromic device(EC D)based on PETI and poly(3,4-ethylenedioxythiophene)(PEDOT)was also constructed and characterized.This ECD had fast response time,high coloration efficiency,better optical memory and long-term stability.2.A novel monomer 2,7-bis(2-(3,4-ethylenedioxy)thienyl)-spirobifluorene(ETS)was synthesized by EDOT and 2,7 dibromo-9,9-spirobifluorene,High performance polymer PETS was prepared.The polymer had good electrochemical activity and electrochromic properties,showed two different colors between pink and sky blue.The electrochromic devices were prepared by PEDOT as cathode coloring materials,and their electrochromic properties were studied.The device converted between yellow and dark blue,which had a fast response time and good stability.The device achieved a high coloration efficiency of 290 cm2 C-1 at 600 nm.3.A novel monomer 4,7-bis(2-(3,4-ethylenedioxy)-5-thienyl)-2,1,3-benzothiadiazole(ETB)was prepared by 4,7-bis(2-bromo-5-thienyl)-2,1,3-benzothiadiazole and EDOT.The corresponding polymer PETB was directly prepared by electrochemical polymerization,and the oxidation potential was 0.75 V.The spectroelectrochemisty study showed that the polymer film can be reversibly transformed between dark green and dark blue.The polymer also showed outstanding electrochromic properties and high coloring efficiency,excellent electrochromic performance.