Medical sensing technology has taken great strides in recent years, with the development of wearable devices that can track pulse, brain function, biomarkers in sweat and more. However, there is one big problem with existing wearable pressure sensors: Even the slightest amount of pressure, something as light as a tight long sleeve shirt over a sensor, can throw them off track.
Texas engineers have solved this problem, which has been vexing the field for years now. And they did it by innovating a first-ever hybrid sensing approach that allows the device to possess properties of the two predominant types of sensors in use today.
“The field of flexible pressure sensors is extremely crowded, and after two decades we hit a bottleneck because no one could solve the tradeoff between pressure and sensitivity,” said Nanshu Lu, an associate professor in the Department of Aerospace Engineering and Engineering Mechanics and the corresponding author of the new research published today in Advanced Materials. “This is the first sensor able to leverage a new hybrid mode to withstand pressure without a significant decay in sensitivity.”
Soft pressure sensors today are generally made of three layers—a deformable sensing layer sandwiched in between a pair of electrodes. These sensors generally fall into one of two categories—piezo-capacitive and piezo-resistive.
Lu’s team utilized an electrically conductive and highly porous nanocomposite as the sensing layer and added an extra insulating layer to the sensor, which gave it capabilities of both types of sensors. This new hybrid sensing is what allows it to better withstand pressure.