Materials scientists have developed a new strategy for crafting one-dimensional nanorods from a wide range of precursor materials. Based on a cellulose backbone, the system relies on the growth of block copolymer “arms” that help create a compartment composed of the inner blocks of the arms to serve as a nanometer-scale chemical reactor. The outer blocks of the arms prevent aggregation of the nanorods.
The structures resemble tiny bottlebrushes with polymer “hairs” on their surfaces. This new technique enables tight control over the diameter, length, and surface properties of the nanorods, whose optical, electrical, magnetic, and catalytic properties depend on the precursor materials used and the dimensions of the nanorods. The nanorods range in length from a few hundred nanometers to a few micrometers, and are a few tens of nanometers in diameter.
Magnetic nanorods in the vial are attracted to a magnet. Researchers have developed a new strategy for crafting one-dimensional nanorods based on cellulose and using a wide range of precursor materials.
The nanorods could have applications in such areas as electronics, sensing devices, energy conversion and storage, drug delivery, and cancer treatment. Using their technique, the researchers have so far fabricated uniform metallic, ferroelectric, upconversion, semiconducting, and thermoelectric nanocrystals, as well as combinations thereof. The research, supported by the Air Force Office of Scientific Research, was reported in the journal Science.
“We have developed a very general and robust strategy to craft a rich variety of nanorods with precisely controlled dimensions, compositions, architectures, and surface chemistries,” said Zhiqun Lin, a professor in Georgia Tech’s School of Materials Science and Engineering. “To create these structures, we used nonlinear bottlebrush-like block copolymers as tiny reactors to template the growth of an exciting variety of inorganic nanorods.”
Nanorod structures aren’t new, but the technique used by Lin’s lab produces nanorods of uniform sizes using materials such as barium titanate and iron oxide, which have not yet been demonstrated in the literature via wet-chemistry approaches. The lab has also produced highly uniform core-shell nanorods made by combining two dissimilar materials. Lin and his former postdoctoral research associate, Xinchang Pang, say the precursor materials applicable to the technique are virtually limitless. — John Toon