Superhydrophobic photothermal graphene composites and their functional applications in microrobots swimming at the air/water interface

[Display omitted] •A novel material with photothermal and superhydrophobic properties is reported.•Microrobots with superhydrophobic and photoresponsive properties are prepared.•A microrobot with multi-modal motion driven by infrared laser is realized.•A water strider-like robot can swim and jump under the control of laser and magnet. Photoresponsive superhydrophobic microrobots based on Marangoni effect are attracting more and more attention. Graphene has high photothermal properties and nanostructures. It is an excellent material for manufacturing superhydrophobic microrobots moving at the air/water interface. However, it is difficult to fabricate superhydrophobic microrobots with complex shapes moving at the air/water interface using graphene without chemical modification. Herein, Graphene/polydimethylsiloxane composite materials were prepared, which exhibited excellent superhydrophobic and photothermal properties. These properties were systematically investigated under various conditions. The developed material exhibits good manufacturability and can be easily made into a variety of small-scale complex structures and different shapes of microrobots with superhydrophobic and photothermal properties. With different structures, it is proved that the microrobots can exhibit a variety of motions, including linear, rotary, and oscillatory, under the action of infrared light. Combined with mechanical analysis, the three motion forms can be integrated into a single microrobot. Finally, a water strider-like robot is fabricated, that can glide and 180° roll-over jump on the water surface, exhibiting good infrared light driving performance and magnetic controllability. This work not only presents a method to prepare superhydrophobic microrobots based on graphene, but also provides a reference for the development of multifunctional microrobots, and further promotes the application of microrobots in liquid detection and oil recovery.