Electrically Conductive Multiwall Carbon Nanotubes/Poly(vinyl alcohol) Composites with Aligned Porous Morphologies

Electrically conductive multiwall carbon nanotubes (MWNTs)/poly(vinyl alcohol) (PVA) composites with aligned porous structure were obtained by a directional freeze-drying process. The results show that the morphologies of the MWNTs/PVA composite can be tailored by adding different contents of MWNTs in the PVA matrix. Because of the aligned porous structure of the MWNTs/PVA composites, the conductivity property of MWNTs/PVA composite does not coincide absolutely with the universal percolation theory. In the aligned porous MWNTs/PVA composites, the existence of the micro-pores destroys the uniform distribution of the conductive network along the direction perpendicular to the aligned pores and results in a nonuniform distribution conductive network. When being used to monitor flowing vapors in pipes, compared with a film sensor with the thickness from several decades to hundreds of microns, the aligned porous conductive MWNTs/PVA composite with micron-sized pores should be a much better sensor.