Structure–property relationship of dodecylbenzenesulfonic acid doped polypyrrole

Dodecylbenzenesulfonic acid (DBSA) doped polypyrroles (PPys) were chemically synthesized in different polymerization times and molar ratios of pyrrole (Py) to DBSA feed. The microstructures of these PPys were investigated by X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR). UV–vis spectrometer, semiconductor parameter analyzer, ubbelohde viscometer, rotation viscometer and electrospinning technique were used to characterize the optical, electrical properties, viscosity, solubility and spinnability of these PPys. The results show that the polymerization time and molar ratio of pyrrole (Py) to DBSA feed have little effect on the optical property of DBSA doped PPys. The conductivity of DBSA doped PPy decreased with the extension of polymerization time and increased with the increase of the molar ratio of Py to DBSA feed. The DBSA doped PPys synthesized for 4 h and 8 h were soluble in dichloromethane, dimethylformamide (DMF) and hexafluoroisopropanol (HFIP), mostly soluble in methanol and ethanol, partially soluble in acetone and formic acid. The solubility in dichloromethane or HFIP of DBSA doped PPys was improved with the extension of polymerization time, but the spinnability of DBSA doped PPy was little affected. All the DBSA doped PPys solutions even in dichloromethane or HFIP did not flow smoothly except the sample synthesized for 8 h, the molar ratio of Py to DBSA feed was 1.5, and were difficult to be fabricated into fibers by electrospinning.