Tough hydrogels for soft artificial muscles

TLDR

Mimicking natural actuating systems offers opportunities in soft robotics, and recent advances in tough hydrogels and manufacturing techniques enable hybrid soft artificial muscles that resemble natural muscle attributes. The review summarizes recent developments in hydrogel‑based actuators and soft artificial muscles and outlines their emerging applications. It discusses hydrogel actuation mechanisms—swelling, diffusion, and mechanical behavior—and details design strategies for tough hydrogel systems, quantitatively comparing their properties to biological tissues. The review concludes by highlighting remaining challenges in developing hydrogel‑based soft artificial muscles.

Abstract

Mimicking the natural actuating systems artificially provides ample opportunities in the field of soft robotics. In this domain, recent advancements in tough hydrogels along with advanced manufacturing techniques have offered us new tools for creating hybrid and soft artificial muscles that resemble the attributes of natural muscles and biological organisms. This review article provides a summary of the recent developments in the field of hydrogel-based actuators and soft artificial muscles and presents a current account of their emerging applications. Further, the fundamentals behind the actuation of hydrogels are discussed with a focus on hydrogels swelling, diffusion, and mechanical behaviour. The design details of different tough hydrogel systems are highlighted, and their physical and mechanical properties are quantitatively compared with biological tissues. Finally, a brief conclusion is provided with remarks on the remaining challenges in this field.