Spatially controllable surface chirality at the nanoscale
Department of Physics, Case Western Reserve University - Cleveland, OH 44106, USA
Accepted: 29 August 2011
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.
PACS: 61.30.Hn – Surface phenomena: alignment, anchoring, anchoring transitions, surface-induced layering, surface-induced ordering, wetting, prewetting transitions, and wetting transitions / 61.30.-v – Liquid crystals / 81.65.Cf – Surface cleaning, etching, patterning
© EPLA, 2011