Surface Textures for Stretchable Capacitive Strain Sensors

Advances in smart materials and electronics have enabled compliant sensing systems mimicking nature. In structural health monitoring (SHM) applications, the technology still lacks accuracy in tracking measurements over large geometries. Herein we report a facile fabrication for a compliant sensor based on an elastomeric capacitive sensor technology, augmented with a scalable surface texture inspired by various grid geometries. Texture designs are selected to direct, and therefore improve, the strain sensing capabilities and thus the sensor's gauge factor. We showcase selected designs based on a detailed engineering analysis. The selected surface patterns are investigated under increasing strain targets and strain frequency sweeps. Results confirm that a stretchable thermoplastic composite sensor with a textured pattern embossed into the hyper-elastic matrix yields approximately 30% increase in the gauge factor and 35% in signal accuracy, great linearity up to 30% strain, and overall signal stability to empower SHM applications. (paper)