The latest breakthrough in cotton fiber research has scientists envisioning hospital gowns that monitor medical patients and jerseys that test athletic performance, according to Cornell University fiber scientist Juan Hinestroza, co-author of a new study that reveals how everyday cotton can be turned into high-tech fabric.
The innovation represents a significant step forward because it lays the groundwork for creating even more complex devices, such as cotton-based circuits, Hinestroza said. This would allow fabrics to sense body temperature, automatically heat up or cool down, track heart rate and blood pressure in high-risk patients, and monitor the physical effort of high-performance athletes.
“Perhaps one day we can even build computers out of cotton fibers in a similar way as khipus – a recording device based on knots and used by the Inca empire in Peru,” Hinestroza added.
Nanoscale modification of natural cotton fibres with conformal coatings of gold nanoparticles, deposition of thin layers of the conductive polymer poly(3,4-ethylenedioxithiophene) (PEDOT) and a combination of these two processes were employed to increase conductivity of plain cotton yarns. This innovative approach was especially designed to fabricate two classes of devices: passive devices such as resistors obtained from electrically conductive cotton yarns, and two types of active devices, namely organic electrochemical transistors (OECTs) and organic field effect transistors (OFETs). The detailed electrical and mechanical analysis we performed on treated cotton yarns revealed that they can be used as conductors still maintaining a good flexibility. This study opens an avenue for real integration between organic electronics and traditional textile technology and materials.
In the study, the first step was aimed at creating a conformal layer of gold nanoparticles over the rough topography of cotton. The next layers were either conductive or semiconductive coatings; the final step was to build the devices. “The layers were so thin that the flexibility of the cotton fibers was preserved,” Hinestroza said.
Two kinds of active transistors, organic electrochemical transistors and organic field effect transistors, were also demonstrated. Both kinds are widely used in the electronics industry as components of integrated circuits, which control the functions of such common devices as phones, televisions and game consoles.