Bio-inspired and programmable Marangoni motor for highly maneuverable and adaptable S-aquabots

Abstract

Mobility, environmental adaptability, and functionality are essential attributes of robots, but these become challenging for small-scale on-water robots, also referred to as S-aquabots. Herein, we propose a programmable Marangoni motor (PM-motor) to propel centimeter-scale S-aquabots with high maneuverability and adaptability. Lightweight, compact, flexible hybrid electronics are used to precisely release ethanol to achieve controllable propulsion, smart sensing, and wireless communication functions. The PM-motor utilizes the surface tension gradient generated by the ethanol, which is released from leaf-inspired veins and improves fuel efficiency by 3.5 times when compared with traditional Marangoni effect-propelled robots. As a result, the device’s endurance is up to ∼226 ​s for a navigation distance of ∼5 ​m with just 1.2 ​mL ethanol. Benefiting from the leaf-like shape and negligible noise production, the S-aquabots can also blend well with their surroundings. Autonomous response capability is demonstrated by guiding an S-aquabot with laser spots to complete a butterfly-shaped trajectory. Equipped with a mini-camera or digital sensors, untethered S-aquabots deployed on an outdoor pool can capture real-time videos or monitor long-term environmental conditions. This work is beneficial for inspiring insightful design strategies to develop S-aquabots with high practical potential.