Tuning Metal-Ligand Crosslinking for Shape-Stable, Self-Healing Capacitive Pressure Sensors

Abstract

Self-healing polymers inspired by biological tissue regeneration pave the way for developing robust, flexible wearable electronic devices. In this work, we report a self-healing capacitive pressure sensor composed of an imine- and metal-ligand-crosslinked self-healing polymer as the dielectric layer, integrated with carbon nanotube (CNT) electrodes. Through fine-tuning of the self-healing polymer dynamic crosslinking ratios, a dielectric material with mechanical rigidity and favourable autonomous self-healing efficiency was obtained, facilitating good film formation and self-repair. The fabricated sensor demonstrated stable performance under pressures ranging from 60 kPa-1 to 1 MPa-1, with minimal hysteresis and high cyclic durability and less fatigue resistance. Crack width and healing time were quantitatively analysed, and the device showed a stable response after five consecutive cut-and-healing cycles. The CNT electrodes retained conductivity throughout, with only minor resistance drift. This work highlights a scalable, intrinsically self-healing pressure sensor with the potential for long-term use in wearable electronics, biomedical devices, and harsh industrial environments.