Researchers at MIT have developed a new sweat-proof material they call “electronic skin.” The new material is described as a comfortable to wear, sensor-embedded sticky patch able to monitor the wearer’s health without malfunctioning or peeling away from the body, even if the person wearing it is sweating. The patch can maintain contact with the body even while sweating, thanks to artificial sweat ducts similar to pores in human skin that were etched into the material’s ultrathin layers.
The pores etched into the patch have a kirigami-like pattern similar to that of the Japanese paper-cutting art. The channels ensure that sweat can escape through the patch preventing skin irritation and damage to the sensors embedded inside it. The design also makes the patch conform to human skin, allowing it to stretch and bend.
It’s the flexibility of new material and its ability to withstand sweat that enables it to monitor the wearer’s health over long periods. The ability to monitor over long periods wasn’t possible with previous electronic skin designs. MIT researchers believe their breakthrough is a step towards long-lasting smart skins that can track daily vitals or the progression of skin cancer and other conditions.
MIT Associate Professor of mechanical engineering, Jeehwan Kim, says that the patch won’t promote sweat accumulation and provide wrong information or detach from the skin, allowing wearable sensors that can perform constant long-term monitoring. The group of engineers that fabricated the new wearable sensor specializes in the fabrication of flexible semiconductor films.
The team pioneered a technique called remote epitaxy, which involves growing ultrathin high-quality semiconductor films on wafers at high temperatures and then selectively peeling away the films. Those thin films can then be combined and stacked to form sensors that are far thinner and more flexible than conventional wafer-based designs.
The key to their breakthrough in combating sweat was increasing the strength and flexibility of the hole pattern by cutting thin channels between each hole, creating a pattern of repeating dumbbells rather than plain holes. That pattern relaxed strain rather than concentrating it in one place, allowing it to conform and giving sweat an escape.