A torsional strain mechanism to tune pitch in supramolecular helices

(Figure Presented) On the turn: Torsional strain has been used to control the pitch of helical nanostructures in the range of tens to hundreds of nanometers. In this method, sterically induced torsional strain on the primary helices forces the secondary helices into superhelices, with the pitch tunable depending on the magnitude of the strain. UV radiation can be used to switch the pitch of specific helical nanostructures (see AFM images). © 2007 Wiley-VCH Verlag GmbH & Co. KGaA.