Researchers create a sea of nano-sized gold stars
Researchers from the Department of Energy's Pacific Northwest National Laboratory (PNNL) and the University of Washington (UW) have successfully designed a bio-inspired molecule that can direct gold atoms to form perfect nanoscale stars. The work is an important step toward understanding and controlling metal nanoparticle shape and creating advanced materials with tunable properties.
Metallic nanomaterials have interesting optical properties, called plasmonic properties, says Chun-Long Chen, who is a PNNL senior research scientist, UW affiliate professor of chemical engineering and of chemistry, and UW–PNNL Faculty Fellow. In particular, star-shaped metallic nanomaterials are already known to exhibit unique enhancements that are useful for sensing and the detection of pathogenic bacteria, among other national security and health applications.
To create these striking nanoparticles, the team carefully tuned sequences of peptoids, a type of programmable protein-like synthetic polymer. "Peptoids offer a unique advantage in achieving molecular-level controls," says Chen. In this case, the peptoids guide small gold particles to attach and relax to form larger five-fold twinned ones, while also stabilizing the facets of the crystal structure. Their approach was inspired by nature, where proteins can control the creation of materials with advanced functionalities.
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