Anisotropic electrical conductivity of MWCNT/PAN nanofiber paper

The electrospinning process has been used successfully to fabricate the multiwalled carbon nanotubes (MWCNTs)-embedded polyacrylonitrile (PAN) nanofiber paper. The diameters of nanofibers decreased with increasing CNT concentration. We found large anisotropic electrical conductivity, i.e., the electrical conductivity of the carbonized nanofiber paper along the spinning direction was about three times larger than that normal to the spinning direction, in good contrast with observations that the carbonized PAN nanofiber paper without CNTs did not reveal anisotropy in electrical conductivity. This proves that CNTs in PAN nanofiber were preferentially aligned along the nanofiber axis, in excellent agreements with transmission electron microscopy observations.