Highly conductive carbon nanotube/polymer nanocomposites achievable?

Carbon nanotubes (NT) have attracted growing interest in recent years as a conducting filler in the development of conductive polymer composites. However, most of experimental results show that the conductivity of NT/polymer composites is significantly lower than expected. Can NTs be an effective conductive filler for improving the electrical conductivity of polymers? In order to answer this question, a continuum model was constructed by introducing effective tunneling conduction in a non-universal network for prediction of electrical conductivity of NT/polymer composites. Based on this model, the effect of the microstructure of NT/polymer composites on conductivity was assessed particularly for NT/polyethylene, NT/polyimide and NT/poly(vinyl alcohol) composites. NT contact resistance and tunneling resistance have significant influences on the conductivity. The effects of the potential barrier of polymer and the tortousity of single-walled NTs on the conductivity were also analyzed. NTs cannot be considered as a valuable conductive filler for the development of highly conductive polymer composites unless the contact and tunneling resistances are reduced significantly.