Decoupling of hygromechanical stimuli without cross-interference enabled by distinct ion-electron charge transport.

Abstract

Accurately decoupling mechanical stimuli and environmental factors such as humidity remains a major challenge in the development of tactile sensors, as cross-interference of these stimuli in sensing signals leads to reduced measurement accuracy and reliability. To address this, we present a distinct ion-electron charge transport-driven sensing mechanism that decouples pressure and humidity under simultaneous hygromechanical conditions. To exploit the distinct charge transport kinetics of ions and electrons, we designed a biphasic dual-conductive elastomer (BiDCE). Through phase separation between ionically and electronically conductive domains, BiDCE achieves multimodal sensing ability without cross-interference between sensing signals. In addition, an impedance spectroscopy-based decoupling method, developed based on the charge transport kinetics of BiDCE, enables real-time quantification of hygromechanical stimuli. The fabricated hygromechanical sensor was integrated into a self-adaptive robotic hand, enabling the simultaneous detection of both contact (pressure) and non-contact (proximity) states of human hands and fingers. This system ensures precise grip control while maintaining safe human-machine interaction and represents a significant advancement in multimodal tactile sensors for robotic skin interfaces.