If you are like me, you are aware of origami (the Japanese art of paper folding) but need a refresher on kirigami. Unlike origami figures that can only be made by folding, kirigami involves both folding and cutting. Inspired by kirigami, researchers at Texas A&M University developed 3D polymer-based kirigami architectures for microelectromechanical systems (MEMS) -type pressure sensors and other structures. One of the researchers’ concerns was the durability and longevity of the structures based on the deformation from stretching, compression and twisting that occurs in potential applications such as wearable electronics, stretchable solar cells and pressure-sensing socks. Also, imperfections in these structures could impact their performance.
In a recently reported study, the researchers repeatedly exerted a downward force on the 3D structures using a diamond flat punch probe. Structures with slight defects, including a small crack on one of the four legs or one slightly thinner leg were part of the test sample. After repeated compressions, the structures were analyzed using an electron microscope and measured the distance the legs bent.
For both defect-free and defective kirigami structures, the researchers found that the compression caused the structures to stiffen and resist the downward force. However, the structures reached a steady-state point and were able to recover from the repeated blows of the diamond punch.
For many potential pressure sensor and other applications, several structures would be used in tandem. For example, to determine how pressure is distributed during gait in smart socks, the results suggest that the miniature pressure sensors will still work quite well even if they are slightly defective.
Filed Under: Sensor Tips
