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2005 Nuggets

Micro/Nanoscale Motors Powered by Catalytic Reactions
(Sen, Catchmark, Mallouk and Crespi, IRG2)

In a project that began as a seed grant and has been incorporated into IRG2, we are investigating micro/nanoscale motors powered by interfacial tension gradients generated through catalytic reactions. Our first achievement was to make striped nanorods with magnetic segments whose direction of motion can be controlled magnetically. In aqueous hydrogen peroxide we observed autonomous movement up to 9 µm/sec, parallel to an applied magnetic field. This movement is comparable to that of multi-flagellar bacteria, such asbacillus cereus). We have also demonstrated controlled rotational movement of a free gear measuring ~100 µm in diameter using interfacial tension gradients. The individual teeth on the gear were partially coated with platinum to produce an platinum/gold interface parallel to the surface of the gear. In hydrogen peroxide, the gear rotates at ~1 sec^-1, corresponding to a linear velocity of ~300 µm/sec at the Pt-coated gear tooth. Videos can be seen at http://research.chem.psu.edu/axsgroup/supporting_information.html.