Researchers develop a solid material with mobile particles that react to the environment

How does one get solid particles to move inside a solid material? „You rarely want this to happen in steel, concrete, or plastics, because free motion usually implies a weak spot in the material. In our active nanocomposites, particles are decoupled from the main material inside small compartments, while the rest remains stable,” says Tobias Kraus, Head of the Structure Formation Group at INM.

The research team used a trick: like raisins in a pudding, they distributed small liquid droplets in a polymer. The droplets contained gold nanoparticles that move freely inside each droplet, something they could not do in the solid:

“The particles are now free to either agglomerate or freely move in the entire droplet. The nanocomposite’s color depends on how far the nanoparticles are from each other, it changes from ruby red to grey-violet in our example. The particles can separate again, and the color change is fully reversible,” explains Professor Kraus.

The naked eye can discern neither the droplets nor the nanoparticles inside. The entire composite is translucent; it simply changes its color depending on temperature. “The result is relevant for applications that require transparent materials. We envision coating it onto clear films, for example,” says the material scientist Kraus.

In the current publication, the particles agglomerate depending on temperature. In the future, the scientists want the nanocomposite to react to chemical stimuli. „One may use this to directly visualize high Vitamin C concentrations or toxins, for example,” ponders Kraus.

Your expert at INM:
Prof. Dr. Tobias Kraus
Head Structure Formation
Phone: +49681-9300-389
tobias.kraus@leibniz-inm.de

David Doblas Jiménez, Jonas Hubertus, Thomas Kister, Tobias Kraus, „A translucent nanocomposite with liquid inclusions of a responsive nanoparticle dispersion“; Advanced Materials, https://doi.org/10.1002/adma.201803159