Artificial multimodal receptors based on ion relaxation dynamics

TLDR

Human skin contains tactile receptors that can differentiate mechanical stimuli from temperature. The study introduces a deformable artificial multimodal ionic receptor capable of distinguishing thermal and mechanical signals without interference. By analyzing ion relaxation dynamics, the device uses charge‑relaxation time as a strain‑insensitive temperature metric and normalized capacitance as a temperature‑insensitive strain metric, measured at two frequencies with a simple electrode‑electrolyte‑electrode structure. The resulting multimodal ion‑electronic skin (IEM‑skin) delivers real‑time force direction and strain profiles across tactile motions such as shear, pinch, spread, and torsion.

Abstract

Human skin has different types of tactile receptors that can distinguish various mechanical stimuli from temperature. We present a deformable artificial multimodal ionic receptor that can differentiate thermal and mechanical information without signal interference. Two variables are derived from the analysis of the ion relaxation dynamics: the charge relaxation time as a strain-insensitive intrinsic variable to measure absolute temperature and the normalized capacitance as a temperature-insensitive extrinsic variable to measure strain. The artificial receptor with a simple electrode-electrolyte-electrode structure simultaneously detects temperature and strain by measuring the variables at only two measurement frequencies. The human skin-like multimodal receptor array, called multimodal ion-electronic skin (IEM-skin), provides real-time force directions and strain profiles in various tactile motions (shear, pinch, spread, torsion, and so on).