Intelligent polymer droplets eject membranes and drive multimodal-propulsion of floating objects
Self-propulsion of bodies floating in water is of great interest for developing new robotic and intelligent systems at different scales. Frequently, the propulsion concept has been related to the Marangoni effect often demonstrated through surfactants. Here we show for the first time that polymer droplets, made of appropriate combination of solvent/polymer, can represent a new strategy to activate different functionalities on water. We demonstrate that, by dispensing such intelligent polymer droplets, it is possible to propel motions with different modalities of any class of floating objects made of different shapes/materials. On demand propulsion and self-rotation (free and along a pivot) are reported for different objects. Furthermore, we discovered that meanwhile the object is propelled, polymer membranes can be created through the spreading phenomena on water’s surface. Such thin polymer membranes can cover extensive areas and follow predefined paths as function on the motion assumed. We report preliminary example of possible exploitation of these new combined functionalities induced by the intelligent polymer droplets for propulsion of multiple objects and water cleaning through particles’ capture. In perspective, the droplet can be endowed with intelligence to control the various operations by knowing a priori the exact location of the delivery and its volume.