摘要 |
A conductive ink for an RFID tag comprises a solvent as well as 90-99.9999 wt.% conductive carbon and 0.0001-10 wt.% dispersant based on the solid content of the ink. When used in an RFID tag, the ink accounts for 2-85 wt.% of the tags solid content. The conductive carbon may be carbon flake/sheet, graphene, natural graphite, ball-shaped graphite, or carbon black flakes, each having a thickness of 1-10000 nm and a grain size of 0.1-100 microns. The dispersant may be ionic, e.g. xanthan gum, carboxymethylcellulose, polyvinylpyrrolidone or non-ionic, e.g. poly(sodium-4-styrenesulphonate), 3-[(3-chloramidopropyl)dimethyl ammonio]-1-propanesulphonate, hexadecyltrimethylammonium bromide, sodium taurodeoxycholate hydrate, or 1-pyrenebutyric acid. An antenna structure for an RFID tag also contains a conductive layer 20 on a fibre substrate 10, the layer comprising 90-99.9999 wt.% conductive carbon and 0.0001-10 wt.% dispersant based on the solid content of the antenna. The conductive layer is printed on the substrate such that part of the layer percolates into substrate pores. |