Sunflower-like materials invented

We are often amazed by the property of sunflower to follow solarmovements, the property of heliotropism. This is explained by the presence of light sensitive hormonesin the sunflower plant, called auxins. Bathed in sunlight, auxins, which are again the growth hormones, migrate to the shadow region causing growth of the stem in the shaded region, bending sunflower in the opposite direction, i.e. towards sun.

Now, the researchers at Tufts University School of Engineering (USA) have developed materials that that move in response to light, just like a sunflower. Such magnetic elastomeric composites can flex, grip, release, or rotate when exposed to light. They get actuated in different manner due to incidence of light, could enable a wide range of products that perform simple to complex movements, from tiny engines and valves to solar arrays that bend toward the sunlight. The results arepublished in the Proceedings of the National Academy of Sciences.

This is due to the unique magnetic properties of these materials that depend on their temperature, which,in turn, depends on the incidence of light. Such materials shaped into films, sponges, and hydrogels, are induced by nearby permanent or electromagnets and can exhibit as bending, twisting, and expansion. Generally, magnetic elastomers like polydimethylsoloxane (PDMS) exhibit this property.

Researchers hope to achieve more complicated and fine-tuned movements, such as folding and unfolding, microfluidic valve switching, micro and nano-sized engines and more for these materials.