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

Abstract

The sharp and broad electron spin resonance ͑ESR͒ signals from nanocomposites of conducting polypyrrole ͑PPy͒ with inorganic Na ϩ-montmorillonite ͑MMT͒ clay were simultaneously observed. The decomposed linewidths (⌬H P-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 ⌬H P-P (ϳ12 G) for the conducting PPy without the Na ϩ-MMT clay. From the analyses of the observed ESR signals, we propose that the narrow ⌬H P-P originates from the weak spin-orbit interaction of the intercalated nanolayers of the nanocomposites, while the broad ⌬H P-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.

Spectroscopy of Nanostructured Conducting Polymers

“…[102], the FTIR spectra of PPy/clay composites showed bands owing to PPy at 1560 cm À1 (2,5-substituted pyrrole), 1050 cm À1 (C -H vibration of 2,5-substituted pyrrole), and 920 and 800 cm À1 (C -H deformation of 2,5-substituted pyrrole); those of MMT clay were shown at 1040 cm À1 (Si -O), 600 cm À1 (Al -O) [103]. In addition, the electron paramagnetic resonance (EPR) data showed a sharp signal with 1-D characteristics [104], which originates from the weak spin-orbit interaction of the intercalated and well-ordered PPy-DBSA nanolayers between the clay layers. Coulomb interactions between the positively charged polymer backbone of the intercalated PPy-DBSA nanolayers and the negatively charged surface of the clay play an important role in enhancing the thermal stability in the PPy-DBSA/clay samples.…”

Conductive Composites Based on Polyurethane and Nanostructured Conductive Filler of Montmorillonite/Polypyrrole for Electromagnetic Shielding Applications

“…Several conductive additives can be used to produce ECPCs, but scientific interest in the use of the intrinsically conducting polymers (ICPs) has been increasing due to their potential in various technological applications. Polypyrrole (PPy) is one of the most widely studied ICPs because of its remarkable and well-known properties, such as high electrical conductivity, chemical and environmental stability, low ionization potential and ease of synthesis 3,4 .…”

Effect of the intercalated cation on the properties of poly(o-methylaniline)/maghnite clay nanocomposites

“…Composites of several conducting polymers with montmorillonite were synthesized under different conditions [12][13][14][15][16][17][18][19][20][21][22][23]. Temperini et al monitored the polymerization of aniline, intercalated into sodium-montmorillonite; they found differences between the structure of the polymer in the nanocomposite and bulk PANI [14,18].…”