Synthesis of Rod-type Polypyrrole doped with p-Toluenesulfonic acid and Characterization of Electrical and Thermal properties

초록

Conducting polymer such as polyaniline (PANI), poly(3,4-ethylene dioxythio-phene) (PEDOT) and polypyrrole (PPY) are promising in this area due to long conjugated length and high conductivity.1 Polypyrrole (PPY) has attracted considerable attention, because of relatively high electric conductivity and effective application for conducting filler to a flexible and transparent polymer conductor, which has a potential as an organic electrode of polymer battery and artificial actuator.2,3 However, particles of conducting polypyrrole are coagulated and precipitate in organic solvent. These coagulation phenomena caused disconnection of conducting polymer particles on polymer web. The TSA used as a dopant in this study is a commercial surfactant with highly water soluble and small size of hydrophobic group. These properties act as advantages on micelle formation. Micelle formed from TSA exhibit structures of high density because it occupies relatively narrow space on micelle compared to other ionic surfactants.3 Resulting particles are mainly affected by the ratio of TSA/pyrrole, and oxidant feeding rate. Each particle of different types (Rod, Grain and partially Rod) exhibits differences on morphology and crystallinity. PPY rod doped with TSA exhibited almost same electric conductivity with granular PPY doped with TSA. However, solubility of PPY (TSA) rod is higher than that of granular PPY. In order to investigate mechanism of rod formation, WAXD patterning analysis is conducted. Characterization of polypyrrole structure affected by TSA concentration is investigated using FT-IR spectra. As a result, PPY rod doped with TSA exhibits dopping effect by TSA. Considerable thermal improvement of PPY rod is observed. Self-orientation of PPY in the micelle of TSA and high crystallinity of rod particle had an effect on improvement of the thermal stability. Thus decomposition temperature of main chain considerably increased. Polypyrrole rod doped with TSA is promising material as conducting filler at blend, because it has high dispersivity, blending processibility with other polymer according to high solubility in organic solvents, ability maintaining form of rod after blending, and thermal stability on high electrical potential.