New Material Developed that Responds to Light

Phototropism is the term that describes an organism’s growth in response to light. Plants respond to light; they move towards it over time as they grow, a phenomena that scientists have observed for as long as they have been studying flora. This is a regular occurrence in organisms that exist in nature, but it is not something that is normally seen in inorganic materials like rocks or metals.

Changing Times

While inorganic materials that exist in nature may not move in response to light, researchers at Tufts University School of Engineering are working on creating new inorganic materials that can. In an article published last week in the Proceedings of the National Academy of Sciences, it is reported that researchers developed new magnetic elastomeric composites that can move in different ways when exposed to light.

The Science Behind the Materials

The materials created by the researchers are based on a principle known as Curie Temperature (or Curie Point), which states that, at a specific temperature, certain materials will lose their magnetic properties. After reaching the Curie Point, the material’s magnetic properties are replaced by induced magnetism. Essentially, by heating certain materials, researchers are able to effectively magnetize and demagnetize certain materials.

In the study, researchers exposed Biopolymers and elastomers doped with ferromagnetic CrO2 to lasers or direct sunlight, raising their temperature. The result was consistent with the Curie Temperature: the materials lost their magnetic properties until they were cooled back down. By “turning on and off” the magnetic properties of the materials, researchers were able to use electromagnets to make the materials move in simple ways, like bending, twisting, etc.

The author of the study, Fiorenzo Omenetto, Ph.D., said “We could combine these simple movements into more complex motion, like crawling, walking, or swimming… and these movements can be triggered and controlled wirelessly, using light.”

Read more about the study here.

The Effects on Spring Design

New materials are always exciting for spring manufacturers, and when it comes to spring design, the concept of materials that can move on their own are rather exciting. Since springs are the parts that give many applications and devices movement and function, think of the possibilities of creating springs that move on their own using light. This could automate the features of applications using the power of the sun. The possibilities could be endless.