Network Formation and Electrical Conduction in Carbon Nanotube Modified Polydimethylsiloxane

Abstract

ABSTRACTThe focus of this research is on network formation and electrical conduction in carbon nanotube polydimethylsiloxane nanocomposites. Carbon nanotube network formation prior to and during polymerization was monitored by means of simultaneous electrical and rheological characterization. Processing induced network formation at filler concentrations below statistical percolation was observed, and both the electrical resistivity and the voltage dependence of the sample resistance were found to increase with the degree of polymerization, indicating carbon nanotube separation during polymer cure. Electron tunnelling through insulating polymer layers was identified as the main conduction mechanism. Information about the final network structure and further details about electrical conduction were obtained from the piezoresistive response of the material. Electron tunnelling was found to be dominant at filler concentrations close to the percolation threshold. With increasing filler concentration a densification of the carbon nanotube network was observed, and the resistance behaviour at high filler content was better described by the behaviour of a parallel circuit.