Electron spin resonance signal of nanocomposite of conducting polypyrrole with inorganic clay

Abstract

The sharp and broad electron spin resonance (ESR) signals from nanocomposites of conducting polypyrrole (PPy) with inorganic Na+-montmorillonite (MMT) clay were simultaneously observed. The decomposed linewidths (ΔHP-P) of the sharp and broad ESR peaks of the nanocomposites at room temperature were 0.44 G and 21 G, respectively. However, we observed one broad ΔHP-P(∼12 G) for the conducting PPy without the Na+–MMT clay. From the analyses of the observed ESR signals, we propose that the narrow ΔHP-P originates from the weak spin–orbit interaction of the intercalated nanolayers of the nanocomposites, while the broad ΔHP-P originates from the bulky conducting PPy on the outside of the clay particles. The thermogravimetric and differential scanning calorimeter results showed that intercalation in the nanocomposites induced the thermal stability. Coulomb interactions between the positively charged polymers of the intercalated nanolayers and the negatively charged surface of the clay play an important role in the sharp ESR signal and the enhanced thermal stability.