Researchers created the antennas, described online September 21 in Science Advances, using a water-based ink containing 1-nanometer-thick flakes of titanium carbide. The ink can be sprayed, painted or printed onto various materials, such as paper, glass or fabric, or fashioned into freestanding films.
Materials scientist and engineer Yury Gogotsi and colleagues at Drexel University in Philadelphia created bendy radio antennas by overlaying titanium carbide films onto sheets of polyester or filter paper. The films ranged from 62 nanometers to 8 micrometers thick — up to about the width of a red blood cell. At about 6 centimeters long, these antennas send and receive radio signals at 2.4 gigahertz, a frequency commonly used for Wi-Fi and Bluetooth communications.
Gogotsi’s team also used titanium carbide films to make radio frequency identification tags, similar to the antitheft tags attached to merchandise at department stores. The researchers’ superslim ID tags can be scanned up to eight meters away. “You can imagine unmanned stores, where every item has a simple and cheap [identification] tag, and those tags are automatically read when a customer leaves the store” to charge that person’s account, Gogotsi says.