Jan 24 2019
At North Carolina State University, scientists have developed novel 3D-printed flexible mesh structures that can be regulated by applying magnetic fields while they are floating on a water surface.
These flexible mesh structures can carry water droplets and grab tiny objects, making them potentially useful as soft robots that can act as tissue scaffolds for cell cultures, or that imitate creatures dwelling on water surfaces.
“This research shows capabilities in the emerging field of combining 3D printing and soft robotics,” stated Orlin Velev, S. Frank and Doris Culberson Distinguished Professor of Chemical and Biomolecular Engineering at NC State and the paper’s corresponding author detailing the study.
In order to develop these unique structures, the team created an “ink” from silicone microbeads, surrounded by liquid silicone and contained in water. The “homocomposite thixotropic paste,” thus obtained, looks like normal toothpaste, which can be effortlessly squeezed out of a tube yet retains its shape on a toothbrush and does not drip. With the help of a 3D printer, the scientists molded the paste into mesh-like patterns and then cured the patterns in an oven to produce flexible silicone structures that can be regulated—expanded and collapsed—by applying magnetic fields.
“This self-reinforced paste allows us to create structures that are ultra-soft and flexible,” stated Sangchul Roh, first author of the study and an NC State PhD student in Velev’s laboratory.
Embedding of iron carbonyl particles, which are widely available and have a high magnetization, allows us to impart a strong response to magnetic field gradients.
Joseph Tracy, Professor, Materials Science and Engineering, North Carolina State University
Tracy is also the senior co-investigator on the project.
The structures are also auxetic, which means that they can expand and contract in all directions. With 3D printing, we can control the shape before and after the application of the magnetic field.
Orlin Velev, S. Frank and Doris Culberson Distinguished Professor, Chemical and Biomolecular Engineering, North Carolina State University
In addition, the properties of the structures enable them to be utilized while floating on water, comparable to water striders, or creatures that hop or skim across water surfaces.
“Mimicking live tissues in the body is another possible application for these structures,” stated Roh.
In the study, reported in a special issue of Advanced Materials Technologies, the scientists demonstrated how they created reconfigurable meshes, a structure that has the ability to “carry” one water droplet and subsequently discharges it on demand via the mesh and a structure that has the potential to “grab” a small ball of aluminum foil.
“For now, this is an early stage proof-of-concept for a soft robotic actuator,” stated Velev.
NC State graduate students Lilian B. Okello, Jameson P. Hankwitz and Jessica A.-C. Liu, and undergraduate student Nuran Golbasi, have co-authored the paper.
The study has been funded by the National Science Foundation under grants CBET-1604116 and CMMI-1663416.
3D printed ultrasoft magnetic mesh
NC State researchers created a 3D-printed soft robot that can grab objects while floating on a water surface. (Video credit: Sangchul Roh, NC State University)