(Printed Electronics World, 9/8/17)
Human skin must flex and stretch to accommodate the body’s every move. Anything worn tight on the body must also be able to flex around muscles and joints, which helps explain why synthetic fabrics like spandex are popular in active wear. Wearable electronic devices that aim to track and measure the body’s movements must possess similar properties, yet integrating rigid electrical components on or within skin-mimicking matrix materials has proven to be challenging. Such components cannot stretch and dissipate forces like soft materials can, and this mismatch in flexibility concentrates stress at the junction between the hard and soft elements, frequently causing wearable devices to fail.