We highlight the significance of multiwall carbon nanotube (MWCNT) shape on the electrical percolation. For rodlike MWCNTs, percolation threshold depends on aspect ratio (L/d). For random coil-like MWCNTs, the percolation threshold does not depend on L/d but depends on the shape factor of MWCNTs represented by the ratio between static bending persistence length and diameter. Surface resistivities of various MWCNTs converge into single curve when we plot their dimensionless surface concentration versus surface resistivity. The surface resistivity of MWCNT films decrease with increasing temperature, particularly at low concentrations, indicating the films can be used as a negative temperature coefficient thermistor.
Bibliographical noteFunding Information:
This study was supported by research grants from the Ministry of Knowledge Economy through the Materials and Component Technology Development Program. HSL thanks Professor W. N. Kim for his advice on this work.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)