Facile route to metal oxide nanoparticles

Metal oxide nanoparticles have been grown with the help of dendritic polymer scaffolds for the first time using a technique developed by Bradley D. Fahlman's group at Central Michigan University (J. Am. Chem. Soc. 2006, 128, 420). Dendrimers have been used in the past to grow metal nanoparticles, but Fahlman points out that metal oxide nanoparticles "are of even greater use for sensors, catalysis, and microelectronics applications." To create SnO₂ nanoparticles, Fahlman and his coworkers mixed sodium stannate with fourth-generation dendrimers of either poly(amidoamine) or poly(propyleneimine). They then bubbled CO₂ into the aqueous or ethanolic solutions, and particles with a diameter of 3 nm formed within 30 minutes. Fahlman notes that, unlike other metal oxide nanoparticle syntheses, his lab's procedure doesn't require elevated temperatures or involve moisture-sensitive reagents. The researchers also found that substituting cheaper hyperbranched poly(ethyleneimine) polymers for the costly dendrimers yields similar results.