Dielectric elastomers studied for use in artificial muscles, soft robots, and medical actuators. Made up of dipolar molecules that align with an electric field, they can expand or converge in response to applied voltage. A dielectric elastomer from North Carolina State University, Raleigh, strengthened by electroactive “bottle bruises“polymers that allow deformation under relatively low electric fields. The polymers also enable the elastomer to maintain the final shape after the field is removed. The work of the team is published in Advanced materials and received funding from the National Science Foundation.
tro GIPHY Dielectric elastomers they can be used in soft actuators as artificial muscles that tighten or expand in response to activated voltage. (Courtesy of Soft Robotics Tool, Youtube)
While dielectric elastomers an external structure, such as a frame or support, is usually required to maintain its shape after the electric field has been switched off, improved elastomer from NCSU there is freedom. As can be seen below, the bottle bruises polymers added to the elastomer bi fada sidechains that makes them work almost like microscopic Velcro. The side chains bind together and are not as easy to loosen as they are elastomer can maintain its shape after activation. In addition, they are thick, but very flexible, so they reduce the elastomer’s total stiffness without the need for melting particles or other materials that may elastomer’s electrical response and freedom capabilities.
The electroactive bottle bruises polymers also significantly reduce the electric field strength required to elastomer. Dielectric elastomers usually requires electric fields on the order of 100 kV / mm to expand. However, the team saw an expansion with electric fields on the order of 10 kV / mm in their circular sample (left).
The bottle bruises elastomers they were synthesized by grafting long polymer side chains onto a polymer backbone. By modifying the grafting methods, the scientists were able to achieve different degrees of polymerization and density to influence the large mechanical properties and stiffness of the elastomer.
Although further research is still needed to determine the suitability of the material, a stand-alone dielectric elastomer they could stand out in the medical industry for applications such as permanent stents or other implants. “We are at the earliest stages of identifying all the ways in which we could use this new class of material,” said Richard J. Spontak, co-author of the paper and distinguished professor of chemical and biomolecular engineering and professor of materials science and engineering at NC State. “It’s working better than expected, and now we’re starting to consider potential applications.”
