Stephen J. Ebbens Jonathan Howse The current state of the art in nanopropulsion devices was recently reviewed by Ebbens and Howse in an article last Friday.[SoftMatter] A short summary of the nano- systems is presented below with video action shots when I could find them. The Whitesides Catalyst: Pt Fuel: H2O2 Propulsion: Bubble propulsion Terrain: Aqueous meniscus Max Speed: 2 cm/s Mitch’s Name: The Karl Benz (since it was the first) Article: Autonomous Movement and Self-Assembly The Sen-Mallouk-Crespi Catalyst: Pt Fuel: H2O2 Propulsion: Self electrophoresis/Interfacial tension Terrain: Settled near boundary in aqueous solution Max Speed: 6.6 um/s Mitch’s Names: The Ford Mustang of nanopropulsion. (It is a hot rod, get it?) Article: Catalytic Nanomotors: Autonomous Movement of Striped Nanorods The Jones-Golestanian Catalyst: Pt Fuel: H2O2 Propulsion: Pure self diffusiophoresis Terrain: Free aqueous solution Max Speed: 3um/s Mitch’s Name: The Volkswagen Beetle Article: Self-Motile Colloidal Particles: From Directed Propulsion to Random Walk The Mano-Heller Catalyst: Glucose oxidase and Biliruben oxidase Fuel: Glucose Propulsion: Self electrophoresis Terrain: Aqueous meniscus Max Speed: 1 cm/s Mitch’s Name: The Komatsu Truck (because it is huge) Article: Bioelectrochemical Propulsion The Feringa Catalyst: Synthetic catalse Fuel: H2O2 Propulsion: Bubble/interfacial Terrain: Acetonitrile solution Max Speed: 35 um/s Mitch’s...

Mirica et al. had an awesome JACS communication out last week. They use magnets to track the progress of reactions. A schematic is shown below. By using a paramagnetic solution (GdCl3) and polymeric beads as their solid support, they monitor the progress of reactions as a function of their beads’ height. The setup is very sensitive to the density (g/ml) of the beads, thus as the beads are chemically modified the height changes. The beads cluster together when they are mostly all starting material or product. They spread out as different beads take different amounts of time to become fully reacted. Some images from their paper and supporting information really highlight this effect. Reprinted with permission from the American Chemical Society: Journal of the American Chemical Society (Dec. 2008). What else can we use magnets in the lab for, ideas anyone? Link to article: Using Magnetic Levitation To Distinguish Atomic-Level Differences in Chemical Composition of Polymers, and To Monitor Chemical Reactions on Solid Supports Mitch