Safer, eco-friendly plastic developed for wearable tech

Researchers at Case Western Reserve University have developed an environmentally safer type of plastic that can be used for wearable electronics, sensors and other electrical applications.

The material, a so-called ferroelectric polymer, is made without fluorine, considered a ‘forever’ chemical that hurts the environment because compounds made with it don’t break down quickly or at all.

Although the researchers are still working to improve the material’s electric and elastic properties, the potential is vast for its flexibility of electronic uses and eco-friendly structure.

“How this material generates its electric properties is also fundamentally new,” said lead researcher Lei Zhu, a professor of macromolecular science and engineering at the Case School of Engineering. “Unlike current ferroelectric materials, it doesn’t have to crystallise to lock in the polarity that gives it electrical properties.”

Polymers are large molecules composed of long chains of smaller molecular units that can be man-made — such as plastics — or natural, like in a person’s hair or DNA. Changing a polymer’s molecular structure and length can vary its strength, flexibility, heat-resistance and ability to be recycled.

Ferroelectricity refers to certain materials with what is known as “spontaneous polarisation” that can be reversed by applying an electric field — like an on–off switch. Ferroelectric materials allow for the development of smaller, more efficient electronic devices, reducing reliance on traditional energy sources.

The new material Zhu and his research team have created is both flexible and has what is known as tuneable electronic properties, which means they can be switched on and off.

They have wide applications in infrared detectors and sensors in wearable electronics, for which the materials need to be soft, pliable and elastic to be compatible with the human body. Conventional ceramic ferroelectric materials are rigid and brittle.

Polymers have the advantage of being flexible and lightweight, but the dominant ferroelectric polymer, poly(vinylidene fluoride), or PVDF, doesn’t naturally degrade in the environment, making it a ‘forever chemical’. The new material is made without fluorine.

Ferroelectric polymers also have applications in sensors for ultrasound diagnostic tools because they are acoustically compatible with biological tissues. They are also potentially useful in augmented and virtual reality (AR and VR) goggles.

“We’re still in the development stage of synthesising small quantities and investigating the properties. But we’re excited about the potential to replace environmentally harmful plastics in sensors and detectors,” Zhu said.

The research explaining the discovery has been published in the journal Science. The new material is patent pending.

Image credit: iStock.com/reklamlar