Electrical conduction of photo-patternable SU8-graphene composites

Graphene-based SU8 nanocomposite is developed as a new conductive polymer, which benefits from remarkable electrical conductivity of graphene, along with photo-pattern-ability and transparency of SU8. Well defined structures with minimal resolution of 10 mu m have been successfully patterned using photolithography technique. The composite exhibits unprecedented high electrical conductivities at low filler loadings compared to other graphene-based polymer composites, owing to the effective dispersion of the graphene nanofillers in the SU8 matrix. In addition, it is shown that the conductivity data imply a vanishing percolation threshold with a large value of the transport exponent, around 6, which is inconsistent with percolation mechanism of transport. Instead, this behavior is interpreted in terms of tunneling processes between well-dispersed flexible graphene flakes. (C) 2014 Elsevier Ltd. All rights reserved.