Ion‐Selective Mobility Differential Amplifier: Enhancing Pressure‐Induced Voltage Response in Hydrogels

Abstract Piezoionics is an emerging mechanical‐electrical energy conversion paradigm that enables self‐powered sensing systems for next‐generation intelligent wearable electronics. However, there are currently no rational design approaches to enhance the stimulus response of piezoionic devices. Here, we present a strategy using crown ether as ion‐selective mobility differential amplifiers for enhancing the pressure‐induced voltage response in ionic polyvinyl alcohol (PVA) hydrogels. The crown ether grafted PVA (PVA‐CE) hydrogel prototype achieves a 30‐fold amplified piezoionic coefficient of 1490 nV Pa −1 within 0–1 kPa, compared to 49 nV Pa −1 of the unmodified PVA. The PVA‐CE exhibits an ultra‐low pressure detection limit of 0.2 Pa with a fast response time of 18.1 ms. Leveraging these properties, we further demonstrate arrayed pressure sensing with a PVA‐CE piezoionic skin, analogous to the human somatosensory network. These capabilities hold great promises for emerging healthcare applications such as synthetic biology, soft robotics, and beyond.