A Facile Strain Visualization Method for Stretchable Serpentine Interconnects

Evaluating the stretchability of stretchable interconnects is crucial for ensuring stable operation in practical applications of stretchable electronics. Conventional methods often involve destructive testing and lack comprehensive strain distribution data. Digital image correlation (DIC) can provide clear strain visualization, but its application to serpentine electrodes, which generally deform in the out‐of‐plane direction, remains challenging. With the growing interest of the in‐plane stretching serpentine electrodes, this study proposes the possibility to resolve the problems in conventional approaches using DIC and thick serpentine electrodes. Herein, a facile method for DIC analysis is presented by utilizing a simple speckle patterning method and optical microscopy. Using this method, the strain distribution in various electrode designs bonded to a soft substrate under extension can be experimentally visualized. Furthermore, the accumulation of plastic strain at various positions on the electrode is investigated. The proposed analysis method offers a new way for evaluating stretchability of serpentine electrodes, which has profound implications for the development and future applications of stretchable electronics.