Revealing Electromechanical Behavior of Graphene-Based Flexible Sensors Using Microscopic Image Correlation

Using full-field strain mapping and electrical measurements, this study outlines the electromechanical behavior of flexible strain sensors coated with graphene and clarifies the relationship between microstrain and electrical response. To measure the microstrain in a graphene matrix that has undergone tensile deformation, the study uses digital image correlation (DIC). This allows for an evaluation of the changes that result in the resistive and conductive properties of the sensor. Concurrent in situ scanning electron microscopy (SEM) imaging provides a spotlight on the microstructural changes in graphene flakes under stress, elucidating the nonlinear electrical resistance behavior that has been observed. The findings highlight the remarkable usefulness of graphene in robotic and wearable applications by demonstrating the material’s susceptibility to strain due to its electrical characteristics. Combining theoretical modeling with empirical findings, a detailed model of the sensor’s operation is developed that takes into consideration the anisotropic and nonlinear responses that are typical of graphene’s electromechanical interactions. The results of this work not only demonstrate the relationship between the electromechanical characteristics of graphene and its microstructural dynamics but also improve the predictive power of sensor behavior under operational stress, hence propelling the development of flexible sensor technology.