Biodegradable Electrohydraulic Actuators for Wearable Haptic Interfaces

Biodegradable soft actuators have gained significant attention due to their inherent conformability, adaptability, and ability to safely interact with humans, while substantially reducing long-term environmental waste. Although various biodegradable materials have been explored for fabricating soft devices and their electrical interfaces, many still suffer from limited durability and operational stability under ambient conditions. In particular, biodegradable electrohydraulic actuators often exhibit a performance degradation over time. In this work, we systematically evaluate the influence of various biodegradable materials, including compliant electrodes, dielectric films, and dielectric fluids, on actuator performance. The optimal material combination was identified and used to fabricate a biodegradable actuator that demonstrated stable operation over 10,000 cycles with no noticeable variation in actuation strain. Under industrial composting conditions, the device underwent degradation within 50 days, supporting its environmental sustainability. Furthermore, a wrist-worn biodegradable haptic device is demonstrated that is capable of generating diverse and salient tactile sensations, highlighting its potential applications in assistive technology and virtual/augmented reality.