Sustainable soft robotics and electronics: from fundamentals to applications

Soft embodiments of robots or electronic devices are often inspired by nature’s diversity. Aiming to unite both digital and animated world, researchers develop life-like robots and electronic skins based on the structure and functionality of natural designs. Sustainability aspects - elemental to all natural life - have been widely neglected in this process. Yet, establishing eco-friendly materials, efficient use of energy, and non-toxic fabrication methods for robotics and electronics is paramount to reduce growing amounts of tech-waste. Combining high-performance, such as durability and good mechanic and electric properties, with environmentally benign design or biodegradability poses the key challenge of this endeavor. This work focuses on sustainable material choices for soft robotics and electronics and addresses questions like ’how can materials and design significantly boost performance to enable devices with longer lifetime but which still degrade after usage. Introduced are biodegradable yet highly resilient biogels with outstanding elastic properties. The biogels are entirely derived from natural and food-safe materials and are easy to fabricate at ambient conditions and low costs. The high stretchability enables soft machines and robots that operate for over 330,000 repeated actuation cycles and skin-like electronic sensor patches that degrade after use. High-performance concepts enabled by fundamental analysis and modeling are introduced for durable stretchable conductors, energy storage, and actuators. Microfabrication of folded ultrathin substrates allows electronics to be stretched over 250,000 times without failure. Battery separators based on stretchable polymerized high internal phase emulsions significantly reduce the internal resistance of soft batteries, increasing capacity and performance of autonomous electronic skins. Electrostatic zipping is realized for actuators at notably lower voltages enabling soft tunable lenses for robotic vision systems. In a brief outlook on future advancements and challenges, this work outlines the next steps for soft robots and electronics towards a more sustainable future.