Researchers at North Carolina State University have created an expandable strain sensor that delivers high sensitivity across broad deformation ranges. The university’s press office reported this advancement.
Measuring strain plays a crucial role in devices that monitor blood pressure or track physical movement. Yet, ultra-sensitive gauges risk damage when overstressed, while sensors designed to stretch far often lose precision. The new design aims to balance both needs, offering strong sensitivity without sacrificing durability under large strains.
Officials describe the sensor as both highly responsive and capable of enduring substantial deformations. An added benefit is reliability under overvoltage conditions, which reduces the chance of failure if forces exceed the intended measuring range.
The core of the sensor is a network of silver nanowires embedded in an elastic polymer. The polymer features a deliberate pattern of parallel cuts that alternate sides along the material: left, right, left, right, and so on.
According to the researchers, this patterned incision approach broadens the range of deformities that can be measured without compromising precision. The sensor detects voltage changes by monitoring resistance shifts. As the material stretches, resistance rises. The surface notches run perpendicular to the stretching direction, serving two purposes. First, the cuts enable large deformations without breaking. When the notches extend into a zigzag shape, the structure remains robust under strain. Second, the opening slits route the electrical signal through a zigzag path, influencing resistance measurements.
To showcase the capabilities of the sensor, the team built tactile devices for blood pressure measurement and a human–machine interface based on the same technology. The same sensor also formed the basis of a three-dimensional touch controller that could interact with a computer game, illustrating potential uses in interactive electronics and medical monitoring alike.
Overall, the development highlights a path toward compact, durable, and highly sensitive strain detectors that can adapt to both small and substantial deformations. By combining conductive nanowire networks with engineered elastic patterns, the approach addresses a common tradeoff in sensor design and opens doors to more versatile wearable and biomedical applications.