Abstract
The doping behaviors of water-soluble poly(3-thiopheneacetic acid) (P3TAA) and ie gel using I$_2$and concentrated HCIO$_4$aqueous solutions were investigated by UV-Visible absorption spectrometer. Electrical conductivity of tile doped polyhiophene gel was also studied. I$_2$-doping of water-soluble P3TAA gave rise to a new broad polaron peak at around 749 nm, which corresponds to localization of electron. It was found that doping ability of P3TAA gel was strikingly dependent on the concentration of HCIQ solution.