A roadmap for flexible and green electronics

(Nanowerk News) A research group lead by Prof. Alireza Dolatshahi-Pirouz at the Technical University of Denmark, is developing a new class of thin-film electronics, which they call "fleco-ionics." This comes from flexible, eco-friendly electronics, and the grand goal of the study is to find green alternatives, to reduce the explosively growing amount of electronic waste.
They use cocoons, woven by silkworms, to extract silk, one of the strongest materials in nature. It is cheap, readily available and biodegradable. In addition it is an ionic conductor.
Prof. Alireza Dolatshahi-Pirouz and his team have transformed this natural polymer into an ionic material with stable performance in both aqueous and chemically active environments, and this enables a wide range of applications within the field of flexible and wearable electronics.
"We need to think simple. Why do we want to do old, complicated chemical syntheses that takes months and years to optimize when we can be smart and look into nature?" stressed Alireza Dolatshahi-Pirouz.
In simple terms, ionic conductors are materials that can conduct electricity mainly through the passage of ions, and they have been utilized to yield flexible Li-ion batteries, stretchable display devices, transparent touchscreens, loudspeakers, and actuators. These materials have brought the field of electronics to a new level, but they still present drawbacks. Notably, most of them have been made of synthetic materials, which are potentially hazardous for humans and the environment. Therefore, research towards ecofriendly alternatives is essential. These conductors could potentially bridge the deep gap that currently exists between electronic devices and greenness.
In a recent paper in Avanced Science ("A Protein-Based, Water-Insoluble, and Bendable Polymer with Ionic Conductivity: A Roadmap for Flexible and Green Electronics"), the team have developed a small motion sensor, which -unlike its predecessors - is not made of environmentally harmful synthetic materials. Instead, it is a fleco-ionic based on silk and nano-sized clay. The production process is extremely simple; they just mix the two components in water! Therefore, this product is incredibly easy to upscale. What's more, it can be recycled again and again and maintains its high electrical sensitivity even after 2,000 bending cycles.
Another promising aspect of the technology developed herein is its low-cost ($0.62/unit) and scalable manufacturing process. This will ultimately make these sensors suitable for mass production without compromising the environment.
The application of these sensors varies from motion sensing gloves (E-gloves) to pressure-sensitive display screens in the electronics industry. The team is now developing a glove equipped with the flexible motion sensors. Supported by DTU's Proof of Concept funding, in 10 months they are ready with the first prototype of their E-glove, which would help surgeons to perform better in operations, translate sign language or even help the golfers improve their technique.
In a similar vein, they are working on flexible sensing systems that readily conform to the curvatures of the body and can measure motions without any discomfort to the user. This would address a number of drawbacks that current motion capture imaging technologies are suffering from in terms of their limited measuring range, low sensitivity, and impractical measuring scenarios.
Source: Technical University of Denmark (DTU)
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