Electrical properties and EMI shielding characteristics of polypyrrole-nylon 6 composite fabrics

Polypyrrole (PPy) was polymerized both chemically and electrochemically in sequence on nylon 6 woven fabrics, giving rise to polypyrrole-nylon 6 composite fabrics (PPy-N) with a high electric conductivity. The stability of the composite prepared by electrochemical polymerization (ECP) on chemical oxidative polymerization (COP) fabric was better than that of the composite prepared solely by the COP process, since the AQSA dopant was able to strongly interact with the PPy main chain and had a large molecular structure. The temperature dependence of the conductivity of the composites was verified over four heating and cooling cycles. The change in conductivity over these four repeated heating and cooling cycles was affected by the interaction between the thermal stability of the dopant and the rearrangement of the PPy main chain. The electromagnetic interference shielding efficiency (EMI SE) values were in the range 5-40 dB and depended on the conductivity and the layer array sequence of the conductive fabric. The composites with a high conductivity represented reflection-dominant EMI shielding characteristics, which are typical of the EMI shielding characteristics of metals. However, composites with low conductivity showed absorption-dominant EMI shielding characteristics. (C) 2003 Wiley Periodicals, Inc.