Dielectric Performance of a Three-Dimensional Self-Healing Anthracene Copolymer Network and Its Application in a Capacitive Tactile Sensor

Abstract

Capacitive tactile sensors are essential to robotics and human–machine interfaces, for which advanced sensing technologies are in high demand. Although polymeric materials offer high flexibility, their inherently low dielectric permittivities limit their performance. To address this, dynamic covalent bonds have been incorporated into polymer networks to endow them with self-healing properties. While hydrogen bond-based self-healing materials are sensitive to ambient moisture, thermally responsive dynamic covalent bonds require direct contact for efficient heat transfer. Such contact causes practical inconvenience and risks unintended deformation in the surrounding areas. In this study, a three-dimensional copolymer network was constructed by cross-linking poly(vinyl alcohol) and poly(ethylene glycol) via reversible anthracene covalent bonds. The resulting polymer network exhibited an optimal dielectric permittivity and desirable mechanical properties. Moreover, anthracene dynamic bonding enables noncontact, light-triggered self-healing in targeted regions using UV irradiation. The tactile sensor, which utilized the proposed polymer material as a dielectric layer, demonstrated good sensitivity of 0.161 kPa^–1 over a wide range from 0.1 to 12.5 kPa^–1 and produced stable signals for up to 10,000 cycles. The device was capable of detecting pressures from human body motion, even after recovering from mechanical damage, owing to its self-healing capability.