Development of ultra-stretchable and conductive tactile sensor based on ionic liquids toward electronic skin

In recent years, major technological advances in the robotics field have increased interest in the development of flexible pressure sensors capable of sensing mechanical stimuli. This can lead to significant changes, not only in biomedical applications, enhancing the treatment and care of patients with disabilities or amputations, but also in areas such as soft robotics and wearable devices, improving human-machine interaction. Here, a soft, conductive tactile sensor based on acrylate ionic liquid, cross-linked with an acrylate polymer and combined with polyimide copper electrodes is presented. Samples with different percentages of resin components have been obtained by photoreticulation process. The different formulations were studied and characterized by electromechanical tests to investigate the tensile and compressive stress sensitivity. The devices exhibit good mechanical properties (maximum elongation strain around 300%), as well as good electrical properties (gauge factor about 1.76) and stability when subjected to cyclic tensile tests with 100% strain. The applicability of this device was evaluated through detecting different signals of the human body. The results indicate that the developed sensors, based on acrylate ionic liquids, are potentially a good starting point for the realization of a stable, conductive, transparent, and low-cost electronic skin.