3D-printed customizable magnetic soft electronics enabled by nanometal oxide-assisted laser activation and magnetic liquid metal

This study introduces a novel strategy based on laser-induced selective metallization technology (LISM) and magnetic liquid metal slurry infiltration to customize magnetic patterning on 3D-printed device surfaces. Incorporating nano zinc oxide (ZnO) into 3D printing resin endows the printed devices with laser activation capability and antibacterial properties. The patterned copper layer is obtained by LISM on the resin surface, and the magnetic slurry is formed by dispersing iron (Fe) particles in liquid metal, which can selectively infiltrate the copper layer, thereby imparting robust magnetic properties to the patterned conductive traces. The 3D-printed electronic devices based on LM-20%Fe@resin have excellent magnetic-thermal and light-thermal conversion capabilities. Demonstrated applications include torpedoes that can move flexibly in water through magnetic or light drives, and caterpillars that move directionally on planes and slopes under magnetic fields. Furthermore, the LM-20%Fe@resin possesses significant antibacterial properties, effective EMI shielding, low cytotoxicity, and enhanced sensing sensitivity due to the Fe particles. This enabled the fabrication of functional devices such as a wearable strain-sensing finger cuff for Morse code decryption and a piezoresistive pressure sensor with a 3D porous structure. Therefore, this method has a promising application in the field of soft robotics, wearable devices, and so on.