Effect of dopant and clay on nanocomposites of polyaniline (PAN) intercalated into Na⁺-montmorillonite (Na⁺-MMT)

The nanocomposites of polyaniline (PAN) and Na⁺-montmorillonite (Na⁺-MMT) were synthesized by emulsion polymerization using dodecylbenzenesulfonic acid (DBSA) or camphorsulfonic acid (CSA) as dopant and emulsifier. In the X-ray diffraction patterns of the systems, we observed that the layer of conducting PAN-DBSA or PAN-CSA between the clay layers was in nanoscale layers (<10 Å). The temperature dependence of dc conductivity [σ_dc(T)] for the nanocomposites followed a quasi-one dimensional (1D) variable range hopping (VRH) model. The σ_dc(T) varied with the dopant used and the molar ratio. From temperature dependent EPR experiments, we obtained the magnetic susceptibility and the line width of the system. The Na⁺-MMT clay layer plays important role for interchain interaction of the system. The effects of dopant and the layer of Na⁺-MMT on charge transport and structure are discussed.