Scientists have found a new way for soft robots to be coated in materials that enable them to move and function more effectively.

Scientists have found a way to coat soft robots with materials that make them more functional and allow them to move more purposefully. The University of Bath led the research and published the results in a paper on March 11, 2022, in Science Advances. The authors of the study believe that their breakthrough modelling of ‘active matter could be a significant step forward in robot design. The concept could be further developed to control soft solids’ shape, movement and behaviour by their natural elasticity and human-controlled activity. An ordinary soft material’s surface shrinks into a sphere. Consider the way water beads into droplets. The beading happens because liquids and soft materials naturally contract to the smallest possible surface area. A sphere. Active matter can be engineered to counter this tendency. This is illustrated by a rubber ball wrapped in nano-robots. The robots work together to create a new shape for the ball (e.g. a star).

Active matter is expected to lead to new machines functioning from the bottom up. Instead of being controlled by a central controller, as is the case with robotic arms in factories today, these machines will be composed of many active units that work together to control their movement and function. This is similar to how our biological tissues work, such as fibres in the heart muscle.

Scientists could use this idea to design soft machines with arms made from flexible materials and robots embedded in them. By coating nanoparticles with active materials, they could adjust the shape and size of drug delivery capsules . This could impact how a drug interacts with cells in the body.

Active matter research challenges the assumption of an energetic cost for a surface of a liquid or soft solid. Because it takes energy to create a surface, a certain amount is required.

“Active Matter makes it possible to look at the rules of nature, such as the rule that surface tension must be positive, in a different light. It’s exciting to see what happens when we break these rules and how we can harness them.

Dr Anton Souslov, the correspondent, said: “This study provides important proof of concept and has numerous useful implications. Future technology may produce soft robots that can easily pick up and manipulate delicate materials.

The researchers created simulations and theories that described a 3D soft material that experiences active stresses. These active stresses cause the material to expand, pulling it underneath and creating a global shapeshift. Researchers discovered that the material’s elastic properties could be altered to alter the shape adopted by the solid.

The researchers will use this principle to create robots that can be used for self-swimming or soft arms in the next phase. They will also examine collective behaviour, such as when active solids are packed together.