1. Penn State MRSEC: Center for Molecular Nanofabrication and DevicesMallouk T.E. DMR-0213623Nano- and Microscale Motors Powered by Catalytic Reactions We are investigating micro/nanoscale motors driven by interfacial tension gradients generated in catalytic reactions. While catalytically driven motion on the nanoscale is ubiquitous in biology, it was previously unknown in artificial systems. Our first achievement was to make segmented nanorods with catalysts at one end. In aqueous hydrogen peroxide we observed linear and rotational autonomous movement at speeds up to 9 µm/sec. The speed of this movement is comparable to that of multi-flagellar bacteria, such as bacillus cereus). By adding magnetic Ni stripes for “steering,” we have made magnetotactic rods that are propelled parallel to an applied magnetic field. We have also demonstrated controlled rotational movement of a free gear measuring ~100 µm in diameter using interfacial tension gradients, and are developing microfluidic pumps based on catalytically driven movement of fluids over patterned surfaces. Figure 1. Linear and rotational catalyzed motion of template-grown striped nanorods in 2.5% aqueous H2O2. Top left: Tracking pattern of three 2 micron long Au/Pt nanorods over 5 seconds. Top right: Catalytic nanowires containing Ni stripes. In a magnetic “steering” field, the motion is directed along the rod axis as shown. Bottom: Cooperative rotational motion of T-shaped assemblies of Au/Pt nanorods. Sequential frames were taken at 0.1 second intervals. W. E. Paxton, T. R. Kline, P. Lammert, S. Subramanian, V. H. Crespi, J. Catchmark, A. Sen, and T. E. Mallouk