A Self-Healing Electrical Impedance Tomography Sensor for the Selective Localization of Compression and Damage Based on a Diels-Alder Conductive Composite

Abstract

Electrical impedance tomography (EIT) tactile sensors are suitable for pressure and tactile sensing on large-scale surfaces due to their simple structure and their capability of spatial continuous measurement. However, their conductive sensing layer is often composed of flexible materials, such as polymers or fabrics, making them susceptible to damage from sharp objects. To address this issue, in this article, we propose a novel self-healing EIT tactile sensor. Its flexible conductive layer is made from a self-healing polymer, which can restore itself through the Diels–Alder (DA) reversible reaction. We achieve a truly selective distinction between pressure and damage areas using the sandwich structure in sensor design. By adopting the artificial intelligence (AI)-enhanced “two-step” imaging method, the experimental result shows an average positioning error of 1.84 mm in the compressed area over a square sensor with an edge length of 100 mm. In the single compressed area cases, the imaging results of the average image correlation coefficient (ICC), relative image error (RIE), and structural similarity (SSIM) are 0.80, 0.59, and 0.92, and those of two and three compressed areas are 0.78, 0.66, and 0.78, respectively. Meanwhile, the undamaged section is still functional for tactile sensing when the sensor is partially damaged. Furthermore, after in situ self-healing and a simple process of updating the baseline voltage, the damaged area fully restores its original functionality.