The sensibility of the composites fabricated from polystyrene filling multi-walled carbon nanotubes for mixed vapors

In this paper, the gas sensitivity of the composites fabricated by polystyrene (PS) filling multi-walled carbon nanotubes (MWCNT) was studied in mixed vapors of THF and water. It is very significant to study the resistance change of MWCNT/PS composites in the mixed vapors including water, because the water vapor almost exists anywhere and anytime. In experiments, a strange phenomenon of resistance rise of MWCNT/PS composites is observed when the composites are transferred into the dried air after their resistances reach the maximum in the mixed vapors with water. The different water vapor partial pressures will result in different resistance changes. Therefore, a new mechanism of parallel electrocircuit was brought forward to explain the phenomenon. Some additional experiments verify the reasonability of the mechanism. These findings would help to understand electrical response mechanism of the composites as promising gas-sensing materials. (c) 2007 Elsevier Ltd. All rights reserved.