3D Printed Biodegradable Soft Actuators from Nanocellulose Reinforced Gelatin Composites

Eco-friendly materials are increasingly important for several applications due to growing environmental concerns, including in robotics and medicine. Within robotics, silicone-based soft grippers are recently developed owing to their high adaptability and versatility allowing to deal with various objects. However, the soft grippers are difficult to recycle and may cause increased environmental impact. Here biodegradable soft pneumatic actuators reinforced by cellulose nanofibrils (CNF) distributed in a matrix of gelatin are presented. The results show that adding CNF enables 3D printability and provides tunable mechanical properties for the actuators. The actuator performance, with a bending angle of 80 degrees and a blocked force of 0.1 N at 15 kPa, is comparable to state-of-the-art mold-casted pneumatic actuators from conventional silicone materials while being exclusively composed of non-toxic, biodegradable materials and fabricated by additive manufacturing techniques. Moreover, the actuators exhibit self-healing ability and enable object manipulation when formed in a gripper configuration. The mold-free approach and achieved functionalities establish new opportunities for soft-robotics, across various fields including healthcare, packaging, or even environmental monitoring. The performance of the gripper shows that CNF can be used in the creation of eco-friendly high-performance soft robots and contribute to the advancement of sustainable and green robotics.