The conductive and extremely water repellent patterned interface acts as a wearable sensor. Credit:
Researchers have developed a highly water-repelling patterned interface by depositing a reactive and conductive ink on printer paper1.
They found that the ink-coated paper was extremely sensitive to body movements. It could detect throat movements when a volunteer wearing the sensor spoke or swallowed water.
The resistance of the material changed during such movements, generating measurable electrical signals, and the researchers suggest it could be potentially used for making highly sensitive wearable sensors.
Metals and other conductive nanomaterials used for sensors develop fatigue after repeated use. To overcome this drawback, Uttam Manna, and his colleagues at the Indian Institute of Technology in Guwahati prepared the conductive ink by mixing three reactive chemicals.
The researchers then generated a water-repelling and conductive pattern on a reactive printer paper by depositing the ink. Twisting, creasing and scratching the ink-coated paper didn’t cause any abrasion on its surface. When the paper was bent, it developed some microcracks which disappeared when the bend was released.
A stream of water bounced on the paper’s surface, which remained stable even when exposed to a wide range of temperatures and relative humidity.
To test its potential as a sensor, the researchers attached the patterned material to different parts of a volunteer's body. It was placed on the person’s throat and he swallowed different volumes of water. When the volume of water was increased, the material’s resistance increased. It could also distinguish between subtle facial reactions when he blinked, smiled or laughed, and larger movements such as walking.
