Achieving Super Sensitivity in Capacitive Strain Sensing by Electrode Fragmentation

Accurate wireless strain monitoring is critical for many engineering applications. Capacitive strain sensors are well suited for remote sensing but currently have a limited sensitivity. This study presents a new approach for improving the sensitivity of electrical capacitance change-based strain sensors. Our technology is based on a dielectric elastomer layer laminated between two fragmented electrodes (i.e., carbon nanotube papers) that, by design, experiences a significant change in resistance (from ω to Mω) when stretched and makes the sensor behave as a transmission line, a well-known structure in telecommunication engineering. The strain-dependent voltage attenuation over the structure length results in a large variation of the effective capacitance (gauge factor exceeding 37 at 3% strain).