Coral polyps that constitute corals found in the ocean are small soft creatures with tentacles and a stem. They nourish the corals and help the corals to survive by producing self-made currents from the motion of their soft bodies.
Demonstration of object attraction and capture by the polyp. The rotating magnet is set to rotate at 300 rpm and UV light set to 169 mW/cm2 is used to address the polyp’s gripper. Video Credit: University of Warwick, Eindhoven University of Technology.
Under the guidance of the Eindhoven University of Technology in the Netherlands, a research team from WMG at the University of Warwick designed a 1 cm x 1 cm wireless artificial aquatic polyp with the ability to eliminate contaminants from water.
Besides cleaning, the soft robot could even be employed in medical diagnostic devices to help pick up and transport particular cells for analysis.
In the study titled “An artificial aquatic polyp that wirelessly attracts, grasps, and releases objects,” scientists illustrate how the new artificial aquatic polyp moves under the impact of a magnetic field, while its tentacles are activated by light.
The rotating motion of the stem of the artificial polyp is induced by a rotating magnetic field present under the device. This motion leads to the generation of an attractive flow that can direct suspended targets, such as oil droplets, towards the artificial polyp.
As soon as the targets are within its reach, the tentacles of the artificial polyp can be triggered by using the UV light, where the tentacles are made of photo-active liquid crystal polymers, which subsequently bend towards the light, enclosing the passing target in the polyp’s grasp. The target release is made possible via illumination with blue light.
Dr Harkamaljot Kandail from WMG was in charge of making advanced 3D simulations of the artificial aquatic polyps. The simulations are crucial to help understand and clarify how the tentacles and stem produce the flow fields required to attract the particles in the water.
The simulations were then utilized to improve the tentacle’s shape to enable it to efficiently and rapidly grab the floating particles.
Corals are such a valuable ecosystem in our oceans, I hope that the artificial aquatic polyps can be further developed to collect contaminant particles in real applications. The next stage for us to overcome before being able to do this is to successfully scale up the technology from laboratory to pilot scale.
Dr Harkamaljot Kandail, WMG, University of Warwick
Dr Kandail continued, “To do so we need to design an array of polyps which work harmoniously together where one polyp can capture the particle and pass it along for removal.”
The artificial aquatic polyp serves as a proof of concept to demonstrate the potential of actuator assemblies and serves as an inspiration for future devices. It exemplifies how motion of different stimuli-responsive polymers can be harnessed to perform wirelessly controlled tasks in an aquatic environment.
Marina Pilz da Cunha, Eindhoven University of Technology
Da Cunha, M. P., et al. (2020) An artificial aquatic polyp that wirelessly attracts, grasps, and releases objects. Proceedings of the National Academy of Sciences. doi.org/10.1073/pnas.2004748117.
Simulations movie of the flow fields induced by the moving polyp (slightly bent 50° configuration) at 300 rpm. Video Credit: University of Warwick Eindhoven University of Technology