Materials and Methods for Sustainable Soft Devices

Soft devices provide unique opportunities in our quest for a more sustainable future. Among the key issues to overcome are the search for high performance green materials, end-of-lifetime considerations in complex (soft) systems, and their energy efficiency. This talk aims at suggesting solutions for some of these grand challenges. We introduce bioderived materials and fabrication methods for soft systems that biodegrade, yet are of high resilience. Based on highly stretchable biogels and degradable elastomers, our forms of soft electronics and robots are designed for prolonged operation in ambient conditions without fatigue, but fully degrade after use through biological triggers. Electronic skins provide sensory feedback, while stretchable and biodegradable batteries enable autonomous operation. 3D printing of biodegradable hydrogels enables omnidirectional soft robots with multifaceted optical sensing abilities. Going beyond, we introduce a systematically-determined compatible materials systems for the creation of fully biodegradable, high-performance electrohydraulic soft actuators. These embodiments reliably operate up to high electric fields, show performance comparable to non-biodegradable counterparts, and survive over 100,000 actuation cycles. Pushing the boundaries of sustainable electronics, we demonstrate a concept for growth and processing of fungal mycelium skins as biodegradable substrate material. Mycelium-based batteries with capacities as high as ~3.8 mAh cm⁻² allow to power autonomous sensing devices including a Bluetooth module and humidity and proximity sensors, all integrated onto mycelium flexible circuit boards.