A conducting nanocomposite via intercalative polymerisation of thiophene in montmorillonite clay

A high yield (90%) in situ intercalative polymerisation of thiophene (TP) was achieved by reacting TP with montmorillonite (MMT) clay alone-with much less pronounced Lewis acidic character than anhydrous FeCl3 or AsF5-in bulk as well as in CHCl3 solvent under reflux condition for 24 h. Formation of crystalline polythiophene (PTP) in the host matrix MMT was endorsed by FTIR and XRD analyses. XRD analyses showed the manifestation of a basal spacing (d-spacing) of 16.47 Angstrom at 2theta = 5.36 for MMT indicating the intercalation of PTP in the MMT structure. TG analyses revealed that PTP-MMT composite was less stable than MMT. TEM studies showed that the average particle sizes of PTP-MMT composite were in 40-160 nm range. Scanning electron microscopic analysis of the composite particle revealed the formation of lumpy aggregates with average size between 6 and 100 mum. The do conductivity of the composite was found to be 103 times higher than that for MMT. A tentative polymerisation mechanism involving formation of a 116 type organometallic complex between [TP] and sorbed cations in MMT unit cell with subsequent conversion to [TP.+] by electron transfer, followed by propagation, was proposed to explain the polymerisation and intercalation. (C) 2003 Elsevier B.V. All rights reserved.