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.