Deposition of conductive materials on textile and polymeric flexible substrates

This paper describes the study, analysis and selection of textile and similar materials to be used as flexible substrates for thin conductive film deposition, in the context of integrating electronics into textiles. Kapton® polyimide was chosen as reference substrate material, was characterized regarding mechanical and electrical properties and was used as a basis for a comparison with several textile substrates. Samples were fabricated using physical vapour deposition (thermal evaporation) to deposit a thin layer of aluminium on top of Kapton and textile substrates. The measurement of electrical resistance of the thin aluminum films was carried out using the Kelvin method. To characterize the mechanical behaviour of the substrate and aluminum film, several mechanical tests were performed and results were compared between Kapton and these textile materials. The chemical composition of the textile substrates and aluminum films as well as the continuity of the films was characterized. This selection process identified the material that was closer to the behaviour of polyimide, a flexible, but non-elastic woven textile coated on both sides with PVC.FEDER funds in COMPETE program and by FCT, in the project FCOMP-01-0124-FEDER-02267

How to equip para-aramide yarns with electro-conductive properties

Electro-conductive textiles are increasingly demanded in our today's technology-driven world as they combine functionalities with high wearing comfort. Thus, they are, for instance, very suitable for being applied as electrodes integrated in clothing to measure biomedical parameters of a person. For this purpose they need to be modified to provide reliable electro-conductive properties. This can be achieved by depositing metals on the textile surface. Copper and gold are good materials to be used for this purpose because of their outstanding electro-conductive properties and possibility to deposit them in form of a thin layer on the surface of a fiber. In this work preference was given to copper. Hence, a thin layer of copper was deposited on synthetic yarns by means of an electroless deposition. This paper states the coating method for the copper deposition on para-aramide yarns. Further, it reports the first results on the characterization of the copper layer and the performance of the resulting yarns