“We have been trying to mimic the function of human skin,” Prof Bao said, noting that skin is stretchable, self-healable and biodegradable. “We have achieved the first two, so biodegradability was something we wanted to tackle.”
The team has created a flexible electronic device that can degrade with the addition of a weak acid, such as vinegar. “This is the first example of a semiconductive polymer that can decompose,” claimed Ting Lei, one of Prof Bao’s researchers.
In addition to the polymer – a flexible, conductive plastic – the team developed a degradable electronic circuit and a biodegradable substrate material. The substrate is flexible and can conform to rough and smooth surfaces. When no longer needed, the device can biodegrade into nontoxic components.
While Prof Bao had previously created a stretchable electrode that could bend and twist, it couldn’t degrade. “We have been trying to think how we can achieve both great electronic properties, but also have the biodegradability,” Prof Bao noted.
The team found that, by ‘tweaking’ the chemical structure of the flexible material, it would break apart under mild stressors. “We came up with an idea of making these molecules using a chemical linkage that can retain the ability for the electron to transport smoothly, [but which] is sensitive to weak acid – even weaker than pure vinegar.”
The team also developed a new type of electrical component, made from iron, as well as a cellulose substrate.
“We envision soft patches that are very thin and conformable to the skin that can measure blood pressure, glucose value, sweat content,” Prof Bao said. A person could wear a specifically designed patch for a day or week, then download the data. And the biodegradable substrate, polymers and iron electrodes are said to make the entire component compatible with insertion into the body.
