Fully Stretchable Electromagnet Using Magnetoactive PDMS Sponges and Metallic Coils

Abstract

Stretchable and flexible devices are being widely developed for the application of modern electronics to biological systems which are soft, elastic, and curved. However, stretchable and flexible electromagnetic and/or magnetic devices are relatively rare, regardless of their importance in many electromechanical systems. Therefore, this study develops a fully stretchable electromagnet using a metallic coil and a magnetoactive polydimethylsiloxane (PDMS) sponge embedded with iron microparticles. In a cylindrical prototype, the magnetoactive PDMS sponge acts as a ferromagnetic core of the electromagnet, enhancing the magnetic fields to ~300% of that of a control device without the iron microparticles. The microscale pores of the PDMS sponge and the spring structures of the metallic coil enable the elongation of the electromagnet up to ~115%. Similarly, we fabricated and experimentally characterized a patch-shaped prototype of a fully stretchable electromagnet, and discussed its practical limitations.