Electrostatic Clutches Based on Ionomer Heterojunctions for Low‐Voltage Switching of Stiffness and Strength

Abstract

AbstractElectrostatic clutches offer electrically programmable control of system stiffness, providing significant advantages in various robotic and haptic applications. However, conventional dielectric‐based electrostatic clutches require high operating voltages, often surpassing several kilovolts, while most low‐voltage electro‐adhesives are unsuitable for electrostatic clutches due to their intrinsic tackiness, resulting in a low switching ratio and reversibility. Here, an electrostatic clutch based on ionomer heterojunctions on rigid electrodes, encased within soft elastomers, capable of switching the system stiffness more than 530‐fold at an operating voltage of just 1 V is presented. Under the reverse bias, the formation of an ionic double layer at the ionomer heterojunction interface enables strong electrostatic adhesion of stiff electrodes at low voltage, yet low tackiness of ionomers allows almost free sliding at the forward bias. The performance of these electrostatic clutches across various geometries and voltages based on the fracture mechanics model is explored. Within this framework, by adjusting the clutch compliance, a force capacity of 50 N cm−2, powered by a 1.5 V battery with an on/off ratio over 250 is achieved, outperforming the latest electrostatic clutches in operating voltage and switching ratio.