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-patternability and transparency of SU8. Well defined structures with minimal resolution of 10 μm 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.