Researchers have developed a new 3D printing method and material for fabricating flexible, soft, mesh structures that can be remotely controlled, opening the door for soft robots with unique capabilities as well as new directions in medical research.
A team at North Carolina State University (NC State) developed the structures, which they can control with applied magnetic fields while floating on water, they said in a news release. The structures can grab small objects and carry water droplets, making them potentially useful soft robots that mimic creatures living on water surfaces, as well as for other uses, such as for cell research.
Researchers at North Carolina State University (NC State) have used 3D printing to fabricate soft, mesh-like structures shown here that can be remotely controlled using magnetic fields. (Image source: NC State)
Two Areas of Study
The work shows the intersection of two scientific areas of study, showing how their combination can be useful for future scientific advancements, said Orlin Velev, a distinguished professor of chemical and biomolecular engineering at NC State. “This research shows capabilities in the emerging field of combining 3D printing and soft robotics,” he said.
Indeed, using 3D printing for this purpose makes the fabrication of soft robots easier and more efficient, researchers said. These robots have a number of advantages over their rigid counterparts, including more safety for human-robot interactions, the ability to move more fluidly, and access to smaller, more confined spaces.
Something Like Toothpaste
To develop the structures, researchers created an “ink” from silicone microbeads that are bound by liquid silicone and contained in water. The resulting material—what’s called a “homocomposite thixotropic paste”—resembles common toothpaste; like the teeth-cleaning agent, it can be squeezed easily out of a tube but then maintains its shape without dripping.
In their research, the team used a 3D printer to shape the paste into mesh-like patterns, which were then cured in an oven to create flexible silicone structures. The resulting structures can be controlled—i.e., stretched and collapsed—by applying magnetic fields to them, researchers said.
“This self-reinforced paste allows us to create structures that are ultra-soft and flexible,” said Sangchul Roh, an NC State Ph.D. student in Velev’s lab and first author of a paper on the work published in the journal Advanced Materials Technologies.
Controlled By Magnetic Fields
Researchers achieved the ability to control the structures using a magnetic field by embedding iron carbonyl particles into the paste, said Joseph Tracy, professor of materials science and engineering and a senior co-investigator on the project. These particles are widely available and have a high magnetization, he said.
“The structures are also auxetic, which means that they can expand and contract in all directions,” Velev explained. This allowed researchers to control the shape both before and after applying the magnetic field using the 3D-printing process, he said.
To prove their method works, the team designed reconfigurable meshes, a structure that could “grab” a tiny ball of aluminum foil, and a structure that can “carry” a single water droplet and then release it on demand through the mesh, they said.
While the experiments show only an early-stage proof-of-concept for a soft robotic actuator, researchers plan to continue their work to create more complex robots, Velev said.
Elizabeth Montalbano is a freelance writer who has written about technology and culture for 20 years. She has lived and worked as a professional journalist in Phoenix, San Francisco and New York City. In her free time she enjoys surfing, traveling, music, yoga and cooking. She currently resides in a village on the southwest coast of Portugal.