Wearable technologies are on the rise. As we know from my recent predictions article for 2018, wearable tech is only going to improve in the next year. Now wearable technologies are about to become even more advanced. Researchers from Iowa State University and the U.S. Department of Energy’s Ames Laboratory have developed low-cost, flexible, highly conductive and water repellent electronic circuits.
Jonathan Claussen and his research group are printing and processing graphene ink to make functional materials. (Source: Christopher Gannon/Iowa State University)
These circuits would advance "wearable technologies that are self-cleaning or washable and allow them to be resistant to stains, biofilm formation and more," according to a recently published paper on this development.
"We're taking low-cost, inkjet-printed graphene and tuning it with a laser to make functional materials," said Jonathan Claussen, an Iowa State University assistant professor of mechanical engineering, an associate of the U.S. Department of Energy's Ames Laboratory and the corresponding author of the paper.
Claussen and the team created electric circuits on flexible and wearable materials using inkjet printing technology. The ink they used was made of flakes of graphene.
Even though they are made of graphene, the printed flakes aren’t highly conductive. The circuits need to be processed to remove non-conductive binders and then weld the flakes together. This process boosts the conductivity, making them useful for electronics.
This post-print process usually uses heat or chemicals, which is not an efficient method because it can damage the surface that the product is printed on. Claussen and his research group have developed a new method that uses a rapid-pulse laser process. This process treats the graphene without damaging whatever material the printing surface is made out of.
The researchers have found another application for this technology. It can turn the graphene-printed circuits that can hold water droplets into circuits that have the ability to repel water.
"We're micro-patterning the surface of the inkjet-printed graphene," Claussen said. "The laser aligns the graphene flakes vertically - like little pyramids stacking up. And that's what induces the hydrophobicity."
According to Claussen, "The energy density of the laser processing can be adjusted in order to change the degree of hydrophobicity and conductivity of printed graphene circuits."
"One of the things we'd be interested in developing is anti-biofouling materials," said Loreen Stromberg, a paper co-author and post-doctoral research associate in mechanical engineering at Iowa State and for the Virtual Reality Applications Center. "This could eliminate the buildup of biological materials on the surface that would inhibit the optimal performance of devices such as chemical or biological sensors."
The technology may have applications in flexible electronics, washable sensors, microfluidic technologies, drag reduction, de-icing, electrochemical sensors and technology that take advantage of graphene structures and electrical stimulation.
According to Stromberg, the graphene printing, processing and tuning technology are useful because "electronics are being incorporated into everything.”
The paper on this research was published in the journal Nanoscale.
