Spatially controllable surface chirality at the nanoscale

Department of Physics, Case Western Reserve University - Cleveland, OH 44106, USA

^a joel.pendery@case.edu
^b rosenblatt@case.edu
^c rolfe.petschek@case.edu

Received: 17 August 2011
Accepted: 29 August 2011

Abstract

We demonstrate a mechanical approach for manipulating surface chirality at nanoscopic length scales. We use an atomic-force microscope to scribe a step pattern, which is chiral in two dimensions, into a polymer-coated substrate, and control chiral strength by varying the steps’ length-to-width ratio R. We determine the chiral strength by coating the surface with a liquid crystal and measuring its rotation on applying an electric field. The chiral strength vs. R is nonmonotonic: zero for R=1, then reaching a maximum, and tending to zero as R→∞. Our results demonstrate that chiral handedness and strength can be precisely controlled mechanically on nanoscopic length scales.