Engineering researchers have created ultrathin, stretchable electronic material that is gas-permeable, allowing the material to “breathe” and making it more comfortable for users — especially for long-term wear.
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. 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 — enabling better contact with the skin and giving the electronics a better signal-to-noise ratio. The gas permeability is important for more than just comfort. If a wearable device is not gas-permeable, it can also cause skin irritation.
To demonstrate the material’s potential for use in wearable electronics, the researchers developed and tested prototypes for two representative applications. 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. The 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 researchers used a wearable textile sleeve integrated with the porous electrodes to play computer games.