Non-equilibrium-Growing Aesthetic Ionic Skin for Fingertip-Like Strain-Undisturbed Tactile Sensation and Texture Recognition

Humans use periodically ridged fingertips to precisely perceive the characteristics of objects via ion-based fast- and slow-adaptive mechanotransduction. However, designing artificial ionic skins with fingertip-like tactile capabilities remains challenging because of the contradiction between structural compliance and pressure sensing accuracy (e.g., anti-interference from stretch and texture recognition). Inspired by the formation and modulus-contrast hierarchical structure of fingertips, an aesthetic ionic skin grown from a non-equilibrium Liesegang patterning process is introduced. This ionic skin with periodic stiff ridges embedded in a soft hydrogel matrix enables strain-undisturbed triboelectric dynamic pressure sensing as well as vibrotactile texture recognition. By coupling with another piezoresistive ionogel, an artificial tactile sensory system is further fabricated as a soft robotic skin to mimic the simultaneous fast- and slow-adaptive multimodal sensations of fingers in grasping actions. This approach may inspire the future design of high-performance ionic tactile sensors for intelligent applications in soft robotics and prosthetics.

Automated summary

Humans use periodically ridged fingertips for precise perception of object characteristics through ion-based mechanotransduction. Designing artificial ionic skins with similar tactile capabilities is challenging due to the contradiction between compliance and pressure sensing. Inspired by the hierarchical structure of fingertips, an aesthetic ionic skin with periodic stiff ridges embedded in a soft hydrogel matrix is developed, enabling strain-undisturbed pressure sensing and texture recognition. This approach can inspire the design of high-performance ionic tactile sensors for soft robotics and prosthetics.