Photo-engineering helices in chiral liquid crystals
Nathalie Katsonis (University of Twentem 7500 AE Enschede, NL)

Helices are a striking expression of chirality and are found at every level of biological materials, from plant cell walls to bones [1]. Helix-based biological materials formed out of equilibrium display multiple length scales, adaptation of structure to function and responsiveness to changing environments, a unique set of features that constitutes a fascinating source of inspiration. However, matching the complexity of biological architectures with artificial systems remains a challenge.
In order to address this challenge our approach consists in using chiral liquid crystals that become photo-responsive when they are mixed with a few percent of molecular switches, such as azobenzenes derivatives or overcrowded alkenes [2]. By using these materials we have been able to demonstrate the unidirectional rotation of microscopic objects, such as microscopic glass rods [3]. Our ongoing work aims at extending these results to the light-controlled patterning of nano-objects, from magnetic nanorods to virus capsids which are being chemically or genetically engineered in our Laboratory [4]. Further, we are interested to use photo-responsive liquid crystals in order to design soft photo-actuators displaying new modes of deformation.