Sprayable Ionic Tattoo Exploiting Biocompatible and Recyclable Organogel for AI‐Assisted Multisignal Sensing

Abstract In the field of human‐computer interaction (HCI), gel‐based ionic tattoos have emerged as a notable innovation owing to their human‐like softness and elasticity. These ionic tattoos are highly valued for their biocompatibility, stability, and user‐experience comfortability. This research has focused on combining the environmentally stable and biocompatible green solvent with dynamically degradable and reusable polymer networks to develop a propylene glycol‐based supramolecular organogel (PGOG). It demonstrates an impressive elongation of 10 400% at break. The photocured PGOG can be recycled on‐demand in water and formulated into a portable spray solution, which can be sprayed on the back of the hand just like a sunscreen spray, providing a seamless and comfortable fit that closely matches the skin's contours. Additionally, an integrated ionic circuit is designed with the capability of sensing temperature, humidity, and strain signals with the assistance of AI, demonstrating its potential application in intelligent artificial skin.