Researchers have created ultrathin, stretchable electronic material that is gas permeable, allowing the material to “breathe.” The material was designed specifically for use in biomedical or wearable technologies, since the gas permeability allows sweat and volatile organic compounds to evaporate away from the skin, making it more comfortable for users – especially for long-term wear.
Specifically, the researchers used a technique called the breath figure method to create a stretchable polymer film featuring an even distribution of holes. The film is coated by dipping it in a solution that contains silver nanowires. The researchers then heat-press the material to seal the nanowires in place.
The resulting film shows an excellent combination of electric conductivity, optical transmittance and water-vapor permeability.
And because the silver nanowires are embedded just below the surface of the polymer, the material also exhibits excellent stability in the presence of sweat and after long-term wear.
The end result is extremely thin – only a few micrometers thick. This allows for better contact with the skin, giving the electronics a better signal-to-noise ratio.
And gas permeability of wearable electronics is important for more than just comfort. If a wearable device is not gas permeable, it can also cause skin irritation.
The first prototype consisted of skin-mountable, dry electrodes for use as electrophysiologic sensors. These have multiple potential applications, such as measuring electrocardiography (ECG) and electromyography (EMG) signals.
These sensors were able to record signals with excellent quality, on par with commercially available electrodes.
The second prototype demonstrated textile-integrated touch sensing for human-machine interfaces. The authors used a wearable textile sleeve integrated with the porous electrodes to play computer games such as Tetris.
News Source: North Carolina State University
