(257i) Chiral Chromatography of Nanomotors

Authors: 
Nourhani, A., The Pennsylvania State University
Lammert, P. E., The Pennsylvania State University
Borhan, A., The Pennsylvania State University
Crespi, V. H., The Pennsylvania State University



Rotary nanomotors (nanorotors) with sizes in the range of 0.1-1 micron have been shown experimentally to execute circular motion on scales as small as the motor dimensions. Orientational diffusion of these nanorotors is unavoidable. The combination of a chiral object and a powered motion superposed by stochastic orientational dynamics leads to long-term translational diffusion. These nanorotors engage in an unusual chiral diffusion: after one period of deterministic rotation, the nanorotor is not equally likely to displace to its left as right. When these chiral nanorotors experience underdamped motion in a chiral potential, orientational diffusion can lead to a much more remarkable effect. An induced drift velocity, which depends on the sense of rotation of the nanorotor, is generic, and can even be comparable to the motor's speed in some parameter ranges. Depending on the form and strength of the chiral potential, the nanorotor demonstrates a range of dynamics from hopping between local minima to linear-like motion with sudden changes in the direction of motion. We will give a tour of the various regimes of motion in this problem, and discuss the possibilities for experimental realization of "chiral chromatography".