A team of researchers from MIT and the University of Delaware has developed a new method for assembling nanoparticles into custom materials using super-flexible connector molecules, a departure from what one researcher called a 20-year dogma that connector ligands need to be rigid.
The research, published today in Nature Materials, demonstrates how flexible ligands with electrically charged tips can control the packing of nanoparticle networks. By allowing the ligands to reorganize as particles come together, the technique enables the formation of previously unseen crystal structures.
Creating better-performing materials often requires precise control over their structure at the nanoscale. Nanoparticles offer customizable building blocks, but assembling them into useful materials has been challenging due to difficulties in controlling how they connect. Previous methods relied on rigid ligands to maintain specific angles, which limited the structures possible and were hard to scale. The new method takes the opposite approach, using flexibility as a tool.
"This is a new approach in nanoparticle assembly that hasn't been investigated before," said Rob Macfarlane, the Richard P. Simmons Professor in Metallurgy at MIT. "It's the exact opposite of what the dogma has been for 20 years: that you need to make connector ligands rigid, and any deviation causes assembly to fail. We showed if you just crank it all the way to the opposite extreme, it works just as well."
The team, which included MIT PhD candidate Nicholas Sbalbi and others, showed they could control connections by changing nanoparticle sizes and ligand chain lengths. The technique successfully assembled nanoparticles into new crystal lattices.
The approach could offer a more versatile way to create high-performing materials for applications in photonics, chemical catalysis, medicine, and agriculture. “Nanoparticle superlattices offer a way to create designer materials where your building blocks have all sorts of unique properties,” Macfarlane said. “This offers a way to get less dense formations of nanoparticles, and that's where a lot of the interesting applications are.”
The work was supported, in part, by the National Science Foundation, the Department of Energy, the U.S. Army, and the U.S. Navy.
Analysis
Why This Matters
- The new method could enable scalable production of custom nanoparticle materials for a wide range of technologies.
- By overcoming a key limitation in nanoparticle assembly, it opens possibilities for materials with tailored optical, catalytic, or medical properties.
- The approach could accelerate the transition of nanoparticle superlattices from research labs to practical applications.
Background
Creating better-performing materials often requires precise control over their structure at the nanoscale. Nanoparticles are promising building blocks due to their tunable shapes and sizes, but assembling them into ordered structures has been hindered by the difficulty of controlling interparticle connections. Traditional strategies involve changing particle shapes or using rigid connectors, both of which limit the range of achievable structures and are often impractical to scale. This new research introduces an alternative based on flexible connectors that spontaneously organize to maximize bond stability.
What to Watch
- Whether the method can be scaled to produce macroscopic materials with consistent properties.
- Further demonstrations of the technique with different types of nanoparticles and applications.
- Development of commercial or industrial uses in areas such as photonics or catalysis.
Checked
11 claims in this story checked against 1 source: 11 supported.
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- SupportedFlexible ligands offer a new way to build nanoparticle materials.MIT News: “The researchers developed a tunable way to use super-flexible connector molecules that regulate the packing of nanoparticle networks”
- SupportedThe team’s approach turns conventional wisdom on its head by using super-flexible connector chains.MIT News: “For their new study, the researchers wanted to turn that approach on its head.”
- SupportedA team including researchers from MIT and the University of Delaware developed a method for assembling nanoparticles into custom materials using super-flexible connector molecules.MIT News: “The researchers developed a tunable way to use super-flexible connector molecules”
- SupportedMacfarlane said, “This is a new approach in nanoparticle assembly that hasn't been investigated before.”MIT News: ““This is a new approach in nanoparticle assembly that hasn’t been investigated before.”
- SupportedMacfarlane said rigid connector ligands had been a 20-year dogma, and that making them extremely flexible worked just as well.MIT News: “It’s the exact opposite of what the dogma has been for 20 years: that you need to make connector ligands rigid, and any deviation causes assembly to fail. We showed if you just crank it all the way to the opposite extreme, it works just as well.”
- SupportedThe research was published today in Nature Materials.MIT News: “In a paper published today in Nature Materials, the researchers showed how connector flexibility and electric charges can be used to tune the network’s structure”
- SupportedThe researchers showed that flexible ligands with electrically charged tips can control how nanoparticle networks pack.MIT News: “The nanoparticles in their new system have flexible ligands with electrically charged tips, some positively charged and others negatively charged.”
- SupportedThe ligands can reorganize as particles come together, enabling the formation of previously unseen crystal structures.MIT News: “The ligands can then reorganize as the particles come together”
- SupportedThe researchers controlled connections by changing nanoparticle sizes and ligand chain lengths, and assembled the particles into new crystal lattices.MIT News: “In experiments led by Sbalbi, the researchers showed they could control the connections by changing the nanoparticle sizes and ligand chain lengths. They also used the technique to assemble the nanoparticles into previously unseen crystal structures.”
- SupportedMacfarlane said nanoparticle superlattices offer a way to create designer materials whose building blocks have unique properties.MIT News: ““Nanoparticle superlattices offer a way to create designer materials where your building blocks have all sort sorts of unique properties,” Macfarlane says.”
- SupportedThe work was supported in part by the National Science Foundation, the Department of Energy, the U.S. Army and the U.S. Navy.MIT News: “The work was supported, in part, by the National Science Foundation, the Department of Energy, the U.S. Army and the U.S. Navy.”
