Pyrolysis of BF4- doped polypyrrole by direct insertion probe pyrolysis mass spectrometry

A systematic structural and thermal characterization of conducting polypyrr ole doped with BF4- was performed using a direct insertion probe pyrolysis mass spectrometry technique. The effect of dopant concentration on the stru cture and stability was investigated not only by analyzing samples with dif ferent doping levels, but also analyzing the dedoped polypyrrole sample. To get a better understanding, the changes in structure and stability upon ov eroxidation and thermal aging were also studied. During pyrolysis, mainly t hree thermal decomposition stages were observed. The first stage below 100 degreesC was associated with evolution of adsorbed water, the solvent aceto nitrile, tetrabutylammonium ion, and unreacted pyrrole. The dopant peaks su ch as BF3. BF2, and BF were recorded at moderate temperatures around 250 de greesC, whereas, polypyrrole peaks showed up in the last stage above which is 300 degreesC. It has been observed that at high BF4- concentrations arom atic structure was enhanced contrary to what was observed for p-toluene sul fonic acid doped polypyrrole in our previous studies.