Development of conductive cotton fabrics for heating devices

Recent developments in the area of textiles to make fabrics more functional have led to synthesizing "intelligent fabrics." This can be achieved by making the fabrics electrically conducting. In the present study it is reported that the cotton fabrics, when impregnated with polypyrrole, achieve enhanced level of conduction. The method of diffusion of pyrrole, followed by polymerization using iron chloride as oxidant, was used. The different levels of conduction were achieved by varying the contents of monomer in the bath from 0.01 to 0.1M during the synthesis. The conductivity could be enhanced from the initial value of 10(-12) to 10(1) S/cm. It is shown that when a fixed voltage is applied to such a modified piece of cloth, the heat generated is up to 1000 W/m(2) depending on the percentage of pyrrole present. Such fabrics can be used as heating pads and integrated into the apparel to keep the wearer warm enough using a portable 9.0-V battery. Being flexible and breathable, such fabrics have better comfort properties (compared with conventional heating pads). It can find applications in dresses for army personnel and old-age patients. Such conductive fabrics can also find applications in many areas such as electromagnetic interference shielding, gas sensors, and temperature indicators. (c) 2006 Wiley Periodicals, Inc.