Moving hydrogels have potential for soft robotics and artificial muscles

The field of soft robotics is developing fast, as it is of great interest to important industries like agriculture and food handling. Developing materials that can change their shape in a similar way to natural muscles also has great potential for medical applications such as prosthetics and tissue engineering. However, such materials have proved difficult to design. Materials scientists and engineers at the University of Texas at Arlington (UTA) are now reporting that they have developed a process by which two-dimensional hydrogels – essentially, thin films – can be programmed to expand and shrink in a way that applies force to their surface, which forces them into complex three-dimensional shapes and motions.

Kyungsuk Yum and his PhD student, Amirali Nojoomi, studied the behaviour of continuously deformable soft tissue such as muscles in nature, to see whether any of the natural properties could be mimicked to create dynamic 3D structures. Yum hit upon an approach using temperature responsive hydrogels whose rates of swelling and shrinking our non-homogeneous: that is, some parts shrink more than others. In a paper in Nature Communications Yum and Nojoomi explain how they developed a digital light 4D printing method (the three linear dimensions plus time) to form such materials.