The first all-polymer transistor was developed in the early 1990s. Since then, stretchable and deformable electronics have found a number of important applications in areas such as medical monitoring, stretchable displays, and wearable computing. These components have been able to undergo mechanical strains of tens of percent.
One area that has been neglected is the creation of high-performance inductors able to undergo similar strains. One major drawback for conventional stretchable inductors is the inability to provide the high-permeability core necessary to obtain high-inductance densities and magnetic coupling.
Recently, scientists at the Army Research Laboratory (ARL) developed a deformable inductive device with a magnetic core formed of an elastomer material. The key to this is magnetic particles dispersed in the elastomer forming a backplane and at least one deformable electrode. The devices are deformable in as much as they enable significant strain in tension, compression, and mixed modes, such as caused by twisting or bending, without failure.
The deformable inductive device may be configured as an inductor, solenoid, transformer or as part of a wireless power transfer system which comprises a coil and a magnetic backplane (the magnetic core) with the coil being attached to or in close proximity to the magnetic backplane. The devices may be configured to be deformed from about -50% strain (in compression) to about 100% strain (in tension). This would be true in any direction of strain being applied, not just parallel and perpendicular directions.
The stretchable magnetic-core solenoid demonstrated by ARL would be ideal for tuning the mechanical properties in magnetorheological elastomer-based soft robotic grippers. The same material is also well-suited as magnetic backplanes for stretchable wireless power.
- Backplane provides a significant improvement in coupling while maintaining the ability to stretch and freely deform
- The magnetic particles include Sendust and molypermalloy (MPP)
- US application number 20170323714 available for license
- Potential for collaboration with Army researchers