No abstract

No abstract

Results of permittivity measurements, electromagnetic interference shielding effectiveness, and heat generation due to microwave absorption in conducting polymer coated textiles are reported and discussed. Intrinsically conducting polymer, polypyrrole doped with anthraquinone-2-sulfonic acid (AQSA) or para-toluene-2-sulfonic acid (pTSA) was applied on textile substrates and the resulting materials were investigated in the frequency range 1-18 GHz. Conducting textile/polypyrrole composites interacted with incident microwaves and generated absorption levels of up to 48 % in a 0.54 mm thick substrate. A thermography station was used to monitor these composites during simultaneous subjection to microwave radiation, where absorption was confirmed via visible heat losses. Lower conductivity samples showed larger amounts of heat loss due to microwave absorption compared to samples with higher conductivity. A sample with an average sheet resistivity of 120 Ω/sq. showed a maximum temperature of 27.15ºC whilst a sample with a lower resistivity (105 Ω/sq.) reached 26.65ºC (Ambient temperature: 22.8ºC).

No abstract

Heating effects in polypyrrole-coated polyethyleneterephthalate (PET)-LycraR fabrics were studied. Chemical synthesis was employed to coat the PET fabrics by polypyrrole using ferric chloride as oxidant and antraquinone-2-sulfonic acid (AQSA) and naphthalene sulfonic acid (NSA) as dopants. The coated fabrics exhibited reasonable electrical stability, possessed high electrical conductivity, and were effective in heat generation. Surface resistance of polypyrrole-coated fabrics ranged from approximately 150 to 500 /square. Different connections between conductive fabrics and the power source were examined. When subjected to a constant voltage of 24 V, the current transmitted through the fabric decreased about 10% in 72 h. An increase in resistance of conductive fabrics subjected to constant voltage was observed. C 2005 Wiley Periodicals, Inc.