Easy fabrication and resistivity-temperature behavior of an anisotropically conductive carbon nanotube-polymer...

An easy fabrication method comprising a slit die extrusion-hot stretch-quench process was used to make carbon nanotubes (CNTs) filled with anisotropically conductive polymer composite (ACPC). CNTs were first premixed with polycarbonate (PC) by coagulation and then melt mixed with polyethylene (PE). During extrusion, the CNT/PC/PE composite was subjected to hot stretching to make the CNT/PC phase form in situ an oriented conductive fibril assembly in the PE matrix. Finally the aligned CNT/PC short fibrils were quenched to preserve their structure. The resultant CNT/PC/PE composite exhibited strong anisotropy in conductivity. This method has the advantages of giving a highly oriented structure with good control of electrical anisotropy as well as the ability to be fabricated in a high rate manner. Temperature-resistivity behavior was investigated by observing the resistivity during isothermal treatment (IT) as well as nonisothermal treatment (NIT). Percolation behavior was seen in the isolated direction during the first IT at 180 degrees C. This was a result of a disordering-induced conductive network. In addition, the positive temperature coefficient (PTC) effect attenuated with IT duration. This was seen in contrast to the remaining negative temperature coefficient (NTC). The unique evolution of PTC and NTC effects originated from the ACPC's special conductive network. It can be seen that this is composed of the originally connected "intrinsic pathway" and isolated "potential pathway".