Imagine taking a piece of paper from your notebook and turning it into a keyboard. Can’t visualize it? Well, now you don’t have to – because a research team from Purdue University has designed a printing process that can actually convert paper into a keypad interface. The technology, published in Nano Energy, has endless creative applications, only a few of which include transforming paper into a music player interface and make food packaging interactive.
“The fabrication of multifunctional electronic devices on ubiquitous paper substrates is gaining considerable attention due to their low cost, environmental friendliness, lightweight, and flexibility,” write the authors. “Unfortunately, the development of paper-based electronics is subject to significant challenges, such as rapid degradation with moisture, battery dependence, and limited compatibility with existing mass-production technologies.” Their technology aims to address that dilemma.
Want to see what the interfaces the team designed look like? Watch the videos below to see how it works:
As you can see in the first video, the paper is first sprayed with an aqueous solution to coat it and make it possible to print onto the paper. The omniphobic coating renders the paper-based electronics insensitive to moisture, liquid stains, and dust.
"This is the first time a self-powered paper-based electronic device is demonstrated," said Ramses Martinez, an assistant professor in Purdue's School of Industrial Engineering and in the Weldon School of Biomedical Engineering in Purdue's College of Engineering. "We developed a method to render paper repellent to water, oil and dust by coating it with highly fluorinated molecules. This omniphobic coating allows us to print multiple layers of circuits onto paper without getting the ink to smear from one layer to the next one."
But not only are these self-powered electronics insensitive to moisture, oil, and dust, they are also foldable and can self-power Bluetooth wireless communication! Not to mention that they are cheap – they cost less than $0.25 per device to manufacture and can generate up to 300 μW/cm of power! All of these characteristics make the technology perfect for large-scale printing processes, bringing smart packaging with human-machine interfaces to many industries.
"I envision this technology to facilitate the user interaction with food packaging, to verify if the food is safe to be consumed, or enabling users to sign the package that arrives at home by dragging their finger over the box to properly identify themselves as the owner of the package," Martinez said. "Additionally, our group demonstrated that simple paper sheets from a notebook can be transformed into music player interfaces for users to choose songs, play them and change their volume."