Not long ago, we reported on a prototype thin, flexible smartphone known as the Paperphone. While it isn't actually made out of paper, the success of a research project at North Carolina State University indicates that phones in the future could be. Scientists there have been able to deposit conductive nanocoatings onto textiles, meaning that items such as pieces of paper or clothing could ultimately be used as electronic devices.
The NCSU team used a process of atomic layer deposition to apply coatings of inorganic materials to textiles such as woven cotton and nonwoven polypropylene, which is commonly utilized in reusable grocery bags. The materials used in the coatings are normally applied to inorganic surfaces, such as those found in devices like solar cells, sensors and microelectronics. The coatings themselves are very thin - thousands of times thinner than a human hair.
In order to quantify the conductivity of the textiles, the researchers had to create a new testing process. Ordinarily, conductivity of materials is tested using a four-pointed probe. A current is applied between two of the points, while the voltage is measured between the other two. These probes were too small to give an accurate reading on textiles, however, so larger probes had to be created.
Besides creating the possibility of textiles being incorporated into flexible, lighter-weight electronic devices, the coatings also have potential applications in the world of smart fabrics.
"Research like this has potential health and monitoring applications since we could potentially create a uniform with cloth sensors embedded in the actual material that could track heart rate, body temperature, movement and more in real time," said Dr. Jesse Jur, NCSU assistant professor of textile engineering, chemistry and science, and lead author of a paper on the technology. "To do this now, you would need to stick a bunch of wires throughout the fabric - which would make it bulky and uncomfortable."
The research was recently published in the journal Advanced Functional Materials.