On the origin of the electrical response of vapor grown carbon nanofiber + epoxy composites

The origin of the electrical response of vapor grown carbon nanofiber (VGCNF) + epoxy composites is investigated by studying the electrical behavior of VGCNF with resin, VGCNF with hardener and cured composites, separately. It is demonstrated that the onset of the conductivity is associated to the emergence of a weak disorder regime. It is also shown that the weak disorder regime is related to a hopping depending on the physical properties of the polymer matrix.

This work is funded by FEDER funds through the "Programa Operacional Factores de Competitividade – COMPETE" and by national funds by FCT- Fundação para a Ciência e a Tecnologia, project references NANO/NMed-SD/0156/2007,PTDC/CTM/69316/2006 and PTDC/CTM-NAN/112574/2009. JS and PC thank the support of the FCT grants SFRH/BD/60623/2009 and SFRH/BD/41191/2007,respectively. The authors also thank support from the COST action MP0902 “Composites of Inorganic Nanotubes and Polymers (COINAPO)”.