The researchers at North Carolina State University have developed a stretchable strain sensor that has an unprecedented combination of sensitivity and range, allowing it to detect even minor changes in strain with a greater range of motion than previous technologies.
The researchers developed new health monitoring and human-machine interaction devices to show the sensor's usefulness.
A silver nanowire network encased in an elastic polymer makes up the novel sensor. The polymer has a pattern of uniformly deep parallel cuts that alternately come from the left and right sides of the material, starting with a cut on the left and moving clockwise around the polymer.
The sensor detects variations in electrical resistance to calculate strain. Resistance rises as the material extends.
The cuts in the sensor's surface run parallel to the direction in which it is stretched. This achieves two goals. First, the cuts let the sensor significantly deform. The surface cuts pull open, forming a zigzag pattern, which allows the material to tolerate significant deformation without breaking.
The electrical signal is compelled to go farther, up and down the zigzag, when the cuts pull open.
