Electronic properties of carbon nanotube/fabric composites

Single walled carbon nanotube (SWNT)/fabric composite materials were manufactured using two simple manufacturing processes. The first method is direct deposition of SWNTs by either a spray method or by incubation; the other is a Quasi-Langmuir-Blodgett (QLB) transfer technique. The composite retains high mechanical strength (governed by the fabric), and good electrical properties (determined by the nanotubes). We measure the DC electrical conductivity of the composite fabric to be 5.33 S/cm for the sprayed tubes, 13.8 S/cm for the incubated SWNTs, and 8 S/cm for the QLB transferred tubes; these values are limited not by the nanotube network, but by the surface roughness of the fabric itself. Measurements of the conductivity up to 1 MHz reveal a transport process that proceeds along a random network, with barriers separating the various nanotubes. The material is resistive both to changes in temperature (range of 0-80 degrees C) and mechanical deformations. The conductivity of the composite decreases by less than 10% when bent around a cylinder of 1 cm diameter. (c) 2005 Elsevier B.V. All rights reserved.