In the just-published paper, "Phase transformations and structural developments in the radular teeth of Cryptochiton stelleri," Kisailus set out to determine how the hard and magnetic outer region of the tooth forms.
His work revealed this occurs in three steps. Initially, hydrated iron oxide (ferrihydrite) crystals nucleate on a fiber-like chitinous (complex sugar) organic template. These nanocrystalline ferrihydrite particles convert to a magnetic iron oxide (magnetite) through a solid-state transformation. Finally, the magnetite particles grow along these organic fibers, yielding parallel rods within the mature teeth that make them so hard and tough.
"Incredibly, all of this occurs at room temperature and under environmentally benign conditions," Kisailus said. "This makes it appealing to utilize similar strategies to make nanomaterials in a cost-effective manner."
Kisailus is using the lessons learned from this biomineralization pathway as inspiration in his lab to guide the growth of minerals used in solar cells and lithium-ion batteries. By controlling the crystal size, shape and orientation of engineering nanomaterials, he believes he can build materials that will allow the solar cells and lithium-ion batteries to operate more efficiently. In other words, the solar cells will be able to capture a greater percentage of sunlight and convert it to electricity more efficiently and the lithium-ion batteries could need significantly less time to recharge.
Using the chiton teeth model has another advantage: engineering nanocrystals can be grown at significantly lower temperatures, which means significantly lower production costs.
While Kisailus is focused on solar cells and lithium-ion batteries, the same techniques could be used to develop everything from materials for car and airplane frames to abrasion resistant clothing. In addition, understanding the formation and prop
|Contact: Sean Nealon|
University of California - Riverside