Synthesis of soluble polypyrrole of the doped state in organic solvents

Polypyrrole soluble in m-cresol and conditionally soluble in chloroform, dichloromethane or 1,1,2,2-tetrachloroethane was synthesized chemically by using dodecylbenzene sulfonic acid as the dopant and ammonium persulfate as the oxidant. The polymer was soluble in m-cresol and became soluble in the weakly poor solvents such as chloroform, dichloromethane and 1,1,2,2-tetrachloroethane when equal amounts of dodecylbenzene sulfonic acid and polymer were added to one of the solvents. Soluble polypyrrole showed the same spectra of FT-Raman scattering and UV-Vis light absorption as those of electrochemically polymerized polypyrrole. The intrinsic viscosity of the soluble polypyrrole in m-cresol was 0.17 dl/g. The solution of the polymer in chloroform was cast to a stiff film with a very smooth surface and the electrical conductivity of the film was 5 S/cm. The redox reactivity of the film was sustained for a long time in cyclovoltammetry.