Hybrid nanostructures, chemical nanomotors, and active matter
Max-Planck Institute for Intelligent Systems, Germany
Tuning the optical, electromagnetic and mechanical properties of a material requires simultaneous control over composition and shape. For instance the realization of optical metamaterials in the visible calls for structures with feature sizes less than the wavelength of light. Nanomaterial applications for energy conversion similarly require that several different materials are combined to form hybrid structures at the smallest of scales. This is at present not possible via chemical means. I will present a parallel fabrication method which we have recently developed that lets us rapidly grow hybrid-nanostructures with a controlled complex 3D morphology and tailored material composition. In one wafer-run we are able to obtain high yields of colloidal metamaterials that contain magnetic, semiconducting, metallic or insulating materials within the same nanostructure. I will then describe how the same fabrication scheme allows us to explore active matter. This can be realized with Janus-like nanostructures. I describe what, to the best of my knowledge, are some of the smallest chemical nanomotors to date. Finally, I present a case where colloidal structures can be propelled (directed) similar to a bacterial flagellum but using weak external magnetic fields. I show how the motion of these structures can benefit from the complex rheology in biological media. Although strong Brownian forces dominate in water we achieve controlled propulsion in biological gels, which paves the way for “nanobot” applications inside biological media and living organisms, and in particular the (extra) cellular matrix.
Peer Fischer is a Professor of Physical Chemistry and he heads the Micro Nano and Molecular Systems Lab at the Max Planck Institute for Intelligent Systems in Stuttgart, Germany. Peer Fischer received a BSc. degree in Physics from Imperial College London and a Ph.D. from the University of Cambridge. He was a visiting scientist at the European Laboratory for Nonlinear Spectroscopy in Florence, Italy (LENS) and a NATO Postdoctoral Fellow at Cornell University, before joining the Rowland Institute at Harvard. At Harvard he held a Rowland Junior Research Fellowship and directed an interdisciplinary research lab for five years. In 2011 he moved his labs to the Max-Planck-Institute for Intelligent Systems.