Gold coated para-aramid yarns through electroless deposition

The interest in electroconcluctive textiles has tremendously increased over the last few years. By functionalizing textile surfaces with thin layers of metal, electrical conductivity can be combined with flexibility and pliability. We adopted this approach and deposited a thin layer of soft gold onto polypyrrole- and copper-coated para-aramid yarns in an electroless way. This paper presents the coating method for the gold deposition and presents some initial results on the characterization of the gold layer and the performance of the resulting yarns. A deposition solution was used which contained a gold salt, sulfite and thiosulfate. The pH value and temperature of the solution was optimized to result in a smooth and homogenous gold layer. Performance tests showed that the coated yarns offered an excellent electrical conductivity combined with good mechanical properties and satisfying resistance to washing. In addition, electrochemical impedance measurements revealed that the gold coated yarns are promising electrode materials to measure biomedical signals. (C) 2009 Elsevier B.V. All rights reserved.