Single-Step Fabrication of a 3D Stretchable Inductor with Multi-jet Modeling Printing Technology

The development of flexible and stretchable electronic devices is crucial for advanced electronics, which necessitate inductors with stable performance under deformation. This work presents the fabrication of stretchable polymeric matrices for 3D inductors through a single-step method via additive manufacturing. A multi-jet modeling (MJM) type 3D printer is used to print a stretchable and rigid hybrid matrix by leveraging the features of high-resolution and multi-component printing techniques. Owing to the presence of access channels designed in multiple directions, the coil channel shows a clean and smooth surface with uniformity. A room-temperature liquid metal, the eutectic gallium indium (EGaIn) alloy, is encapsulated in the designated channels without any leakage under mechanical deformation. Electrical performance tests demonstrate that the MJM-printed solenoid and toroid inductors maintain stable performance under bending and stretching deformations, which is suitable for soft electronic applications. Additionally, a flexible helical structured inductor is fabricated and tested as a wireless power receiver inductor. It generated an output voltage of more than 10 V, sufficient to power a red LED light bulb. These results highlight the simplicity and effectiveness of multi-jet 3D printing for fabricating a stretchable and rigid hybrid matrix for the inductors at once, with excellent mechanical deformability and electrical performance.