Abstract
Summary: Pyrrole and 3β(3,6βdioxaheptyl)pyrrole were polymerized in the presence of an oligo(oxyethylene monomethylether) sulfonate (DP~PEO~β=β17) with ammonium peroxydisulfate as an oxidizing agent and dry chloroform as a solvent. The oligo(oxyethylene) sulfonate acted as a phase transfer agent and also became incorporated into the polymer as a counter ion. The polymers were obtained as gelβlike particles that could be easily dispersed in organic solvent and could be doped with lithium triflate to enhance the ionic conductivity of the electronically conductive materials. DSC and Xβray measurements showed a glass transition (T~g~) in all samples at around β40βΒ°C which is related to the dynamics of the EO segments. In addition, the system composed of polypyrrole with oligo(oxyethylene) sulfonate counter ions showed partial crystallinity and a melting transition at 34βΒ°C. Conductivity was explored by impedance spectroscopy with regard to frequency and temperature dependence. The data could be evaluated in the coordinates of an Arrhenius plot as the sum of two Arrhenius functions in all cases. Although one Arrheniusβtype function was sufficient to describe the temperature profile of the conductivity below T~g~, a second term needed to be added at Tβ>βT~g~. The absolute values of conductivity were also dependent on the level of doping with lithium triflate. These phenomena were interpreted as a contribution of ionic conductivity by the lithium ions to the electronic conductivity, which comes about from the oxidation state of the polypyrrole backbone.
A good Liβion conducting polymer which also exhibits electronic conductivity.
magnified imageA good Liβion conducting polymer which also exhibits electronic conductivity.