Effect of montmorillonite/polypyrrole ratio and oxidizing agent on structure and electrical conductivity of intercalated nanocomposites

Polypyrrole/montmorillonite (PPy/Mt) nanocomposites with different amount of PPy were prepared using two different oxidizing agents, ammonium peroxydisulfate and ferric chloride. The nanocomposites in powder form were studied using thermogravimetry, X-ray powder diffraction, infrared and Raman spectroscopy, molecular modeling, and electrical measurements. Structure and conductivity of the nanocomposites in dependence on the PPy amount and the oxidizing agent used were compared with pristine PPy samples. Use of ferric chloride led to the conductivity two orders of magnitude higher in comparison with ammonium peroxydisulfate. Molecular modeling revealed regular arrangement of PPy chains in Mt. interlayer space and higher intercalation rate for samples prepared using ferric chloride. Tablets pressed from the nanocomposites exhibit anisotropy in electrical conductivity. Surface morphology of the tablets was studied using atomic force microscopy. For PPy amount similar to 32 mass%, the highest conductivity (49 S/m) and anisotropy factor (224) were reached. Possible use of the tablets as pressure sensors was demonstrated.