Physical characterization of polyaniline-Na+-montmorillonite nanocompositeintercalated by emulsion polymerization

We report the results of temperature dependence of de conductivity (sigma ( dc)(T)), X-ray photoelectron spectroscopy (XPS), electron paramagnetic reso nance (EPR), and X-ray diffraction (XRD) experiments for dodecylbenzenesulf onic acid (DBSA) doped polyaniline (PAN)-Na+-montmorillonite (MMT) nanocomp osite. The PAN-Na+-MMT nanocomposite was synthesized by intercalating the e mulsion of aniline monomer with zylene and DBSA in the layer of Na+-MMT wit h distilled water and then initiating the polymerization of aniline inside the layer of Na+-MMT. From the results of X-ray diffraction experiments, we observe the insertion of PAN-DBSA between the interlayer of the Na+-MMT, w hose separation consequently becomes larger (1.52 nm) than in a polymer-fre e clay (0.96 nm). The sigma (dc) Of the systems is similar to 10(-1) S/cm a t room temperature, and its temperature dependence follows a quasi one-dime nsional variable range hopping (VRH) model. The slope of sigma (dc) is simi lar to7.0x10(3) K. From the result of XPS experiment, we obtain the doping level of the system quantitatively. We measure temperature dependence of EP R linewidths. Base on those results, we discuss the effect of the layer of montmorillonite on PAN-DBSA samples. (C) 2001 Elsevier Science B.V. All rig hts reserved.