Hydrogels – Programmable Materials to Create Complex Movement


Programmable hydrogels can be applied to the technology including bioinspired soft robotics and artificial muscles

Researchers at the University of Texas, Arlington have developed a process by which 2D hydrogels can be programmed to expand and shrink in a space and time controlled way that applies force to their surfaces enabling the formation of complex 3D shapes and motions.

This process could transform the way soft engineering systems or devices are designed and fabricated. The applications for the technology include bioinspired soft robotics, artificial muscles and programmable matter. Well, the concept is also applicable to other programmable materials.

Properties that allow hydrogels to swell and shrink

For this, researchers used temperature-responsive hydrogels with local degrees and rates of swelling and shrinking. Those properties allowed them to program how the hydrogels swell or shrink in response to temperature change using a digital light 4D printing method, they developed includes three dimensions plus time.

Using this method, they can print multiple 3D structures simultaneously in a one-step process. Then, they mathematically program the structures’ shrinking and swelling to form 3-D shapes, such as saddle shapes, wrinkles and cones and their direction.

They also developed design rules based on the concept of modularity to create even more complex structures including bioinspired structures with programmed sequential motions. This makes the shapes dynamic so they can move through space. Researchers can control the speed at which the structures change shape and can also create complex, sequential motion, such as how a stingray swims in the ocean.

Unlike traditional additive manufacturing, digital light 4D printing method allows printing multiple, custom-designed 3D structures simultaneously. Moreover, the researchers claimed that the approach to creating programmable 3D structures has the potential to open many new avenues in bioinspired robotics and tissue engineering. The speed with which this approach can be applied as well as its scalability makes it a unique tool for future research and applications.