Elastomeric high-κ nanocomposites coupled with stretchable conductive adhesives for capacitive force sensors

Abstract

As practical interest in wearable electronics and biomimetic transducers increases, there is increasing demand for elastomeric high-kappa composite-based capacitive force sensors with both reliable-performance and favorable mechanical properties. While previous research has focused on the structural design of dielectric layers or the development of high-kappa materials, studies addressing the role of the electrode-dielectric interface remain limited. Here, we demonstrate that strong interfacial adhesion between the electrode and dielectric layer is critical for achieving stable interfacial polarization and reliable sensing performance under mechanical stress. Among various electrode materials, the silicone-based stretchable conductive adhesive (SCA) not only offers dielectric performance comparable to that of sputtered Pt or liquid metal electrodes, but also provides superior mechanical compliance and interfacial stability. Due to the strong and conformal interfacial adhesion between the SCA electrode and the dielectric layer, the fabricated sensor exhibits a continuous increase in capacitance change with applied pressure, even at a high pressure of 346 kPa, while maintaining negligible hysteresis. The device also demonstrates robust performance over 10,000 loading/unloading cycles at 346 kPa, with minimal signal drift (<0.2 %). Furthermore, the sensor maintains a consistent pressure-dependent capacitance response under a bent configuration with a bending radius of 1.5 cm. These results highlight the importance of interface engineering in the design of high-performance, mechanically robust capacitive sensors.