Liquid metal-elastomer composites with dual-energy transmission mode for multifunctional miniature untethered magnetic robots

Abstract

Miniature untethered robots attract growing interest as they have become more functional and applicable to disruptive biomedical applications recently. Particularly, the soft ones among them exhibit unique merits of compliance, versatility, and agility. With scarce onboard space, these devices mostly harvest energy from environment or physical fields, such as magnetic and acoustic fields and patterned lights. In most cases, one device only utilizes one energy transmission mode (ETM) in powering its activities to achieve programmed tasks, such as locomotion and object manipulation. But real-world tasks demand multifunctional devices that require more energy in various forms. This work reports a liquid metal-elastomer composite with dual-ETM using one magnetic field for miniature untethered multifunctional robots. The first ETM uses the low-frequency (<100 Hz) field component to induce shape-morphing, while the second ETM employs energy transmitted via radio-frequency (20 kHz-300 GHz) induction to power onboard electronics and generate excess heat, enabling new capabilities. These new functions do not disturb the shape-morphing actuated using the first ETM. The reported material enables the integration of electric and thermal functionalities into soft miniature robots, offering a wealth of inspirations for multifunctional miniature robots that leverage developments in electronics to exhibit usefulness beyond self-locomotion.