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Many proposed technologies hinge on the organization of nanoparticles into layers called films that have a precise microstructure. Fabricating these films is challenging because it is difficult to control the structure of nanoparticle assemblies on micrometer scales.

However, Carnegie Mellon researchers have found a solution—nanoparticles can be organized in a more predictable, organized fashion when surface-modified with polymer chains.

By harnessing the organizational properties of polymeric tethers, nanoparticles can be programmed to self-assemble into a variety of micron-sized domain structures in a reversible way.

These findings were published in the December 23 issue of Science Advances, in an article called “Polymer ligand-induced autonomous sorting and reversible phase separation in binary particle blends.”

“We have shown that you can control interactions between nanoparticle building blocks, and therefore you now have the ability to create molecular structures with particles which was not previously possible,” says Professor of MSE Michael Bockstaller, a lead author on the study.

“No one has been able to control particles in this way before, so this finding is exciting,” says Bockstaller.

The researchers have demonstrated this new approach for a model particle system that will act as a synthetic testbed for a range of other nanoparticle materials.

Their results mark an important stepping stone for improving the efficiency of sensors and solar panels. These technologies rely on the organization of particles to propagate light and heat, so this finding has the potential to dramatically change the way materials function. Bockstaller explains that better control over the organization of fluorescent particles called quantum materials could result in brighter, more energy-efficient television and smartphone screens.

Moving forward, the research team plans to explore the organization of new nanoparticle systems, including quantum dot materials. The team, which includes Chemistry Professor Krzysztof Matyjaszewski, hopes to extend the level of sophistication in controlling the morphology and properties of nanoparticle assembly structures.

“This fundamental research opens the door to new ideas in the realm of nanoparticle-based materials, from photonic to luminescent materials,” says Bockstaller. “Imagine if we were able to dynamically change the properties of these materials in defined ways. With our understanding of how to organize particles, we hope to make this future possible.”