Preparation and electrical conductivity of polypyrrole/WS2 layered nanocomposites

Lithium intercalated tungsten disulfide LixWS2 with x > 1 was solvothermally obtained. It was revealed that LixWS2 can remain mostly unchanged under vacuum (about 4 kPa) for 5 days. The pH dependences of surface zeta potential for single molecular layers of WS2 were determined, illustrating that its isoeletric point is approximately at pH 3. The polypyrrole/WS2 layered nanocomposites were prepared via the combination of the exfoliation-restacking technique and in situ oxidative polymerization. The intercalation of PPy into the host galleries resulted in an interlayer expansion of about 3.7 angstrom, which suggested that the intercalated polymeric chains are in a monolayer arrangement with the pyrrole rings lying parallel to the WS2 host layers. The resulting material shows good thermal stability with the decomposition of the interacted chains within the disulfide galleries occurring at around 400 degrees C. The electrical conductivity of PPy/WS2 nanocomposite was found to be high in the order of 10(-2) S cm(-1) at ambient temperature. (C) 2008 Published by Elsevier Inc.