Colloquium: September 17, 2014
Three-Dimensional Hybrid Nanostructures,
Chemical Nanomotors, and Nanorobot Propulsion
|September 17, 2014 Wednesday||15:40||EE01|
Host: F. Ömer İlday
ABSTRACT — Tuning the optical, electromagnetic and mechanical properties of a material requires simultaneous control over composition and shape. For instance the realization of opticalmetamaterials in the visible calls for structures with feature sizes less than the wavelength of light. At these small sizes, it is challenging to fabricate complex 3D structures, because surface-energy minimization generally leads to compact high-symmetry shapes. I will present a parallel fabrication method which we have recently developed that lets us rapidly grow hybrid-nanostructures with controlled complex 3D morphology as well as material composition. In one wafer-run we are able to obtain high yields of colloidal metamaterials that can contain magnetic, semiconducting, metallic and insulating materials within the same nanostructure. The technique’s versatility has allowed us to create chiral plasmonic films and metafluids with record optical activities. I will then describe how the same fabrication scheme allows us to explore active matter. I report, what to the best of my knowledge, are the smallest synthetic chemicalnanomotors to date. Janus nanoparticles with a diameter of ~30 nm that can catalyze the decomposition of hydrogen peroxide to oxygen and water. Finally, I will discuss “swimming” at low Reynolds number and show how colloidal structures can be propelled (directed) by external fields similar to a bacterial flagellum. Although strong Brownian forces dominate in water werecently achieved controlled propulsion in biological fluids, which paves the way for “nanorobot” applications inside tissues and living organisms.
*Max Planck Institute for Intelligent Systems, Stuttgart, Germany
The Physics Colloquia are designed to address a non-specialist, broad audience and introduce topics of contemporary research through lectures by leading experts. We warmly invite all members of the student body, including undergraduates enrolled in any programme.