Plant-inspired robot mimics osmosis for movement

Osmosis allows plants to transport water internally by relying on the variation of solute concentrations either side of semi-permeable membranes. Water travels across the membrane to equalise the concentration on both sides. Scaled up from the cellular level, the process controls hydraulic plant movement such as tendrils curling or climbing.

Developed at the Istituto Italiano di Tecnologia (IIT) in Genoa, the robot is made of a flexible PET tube containing a liquid with electrically charged particles. Using a 1.3 Volt battery, the ions are attracted and immobilised on the surface of flexible electrodes at the bottom of the tendril, and the corresponding movement of the water causes the robot to flex and curl. To reverse the motion, the power source is simply switched off. According to the researchers, this is the first time such a system has been implemented in a soft robot, and the breakthrough could influence everything from wearable technology to industrial robotics.