Flexible carbonized cellulose/single-walled carbon nanotube films with high conductivity

A carbonized cellulose/single-walled carbon nanotube composite film (cell/SWCNTcarbon) was prepared with well-dispersed cellulose/SWCNT doped in N-methylmorpholine N-oxide (NMMO) monohydrate. After carbonization at 400 degrees C, the SWCNT content at electrical threshold of the cell/SWCNTcarbon nanocomposite decreased from 2 wt% to 1 wt%, and the electrical conductivity of the cell/SWCNT(1 wt%)(carbon) nanocomposite (0.6 S cm(-1)) increased by more than 6 orders of magnitude compared to that of pure carbonized cellulose (1.1x10(-7) S cm(-1)). Further, it continuously increased as the carbonization temperature increased and reached 100 S cm(-1) when the cell/SWCNT(1 wt%) nanocomposite was carbonized at 1400 degrees C. This drastic increase in the electrical conductivity at low carbonization temperatures (e.g. 400 degrees C) was due to the percolation of small carbon clusters with conducting SWCNTs. The incorporated SWCNTs improved flexibility and mechanical stability during carbonization so that the cell/SWCNT(1 wt%)(carbon) nanocomposite could be bent even after carbonization at 1400 degrees C; however, the carbonized cellulose prepared using the same method was too brittle. This cell/SWCNTcarbon nanocomposite may render the eco-friendly production of flexible electrodes for various applications, including heat sink parts, electromagnetic interference shielding materials, and electronic devices, feasible.