Three dimensional self -assembly of chiral nematic colloidal crystals

Abstract

We study pair interactions and self-assembly of 3D colloidal structures in chiral nematics. Laser tweezers -assisted quenching of the local nematic order was used to study the pair interactions in chiral nematic colloids. The self-assembly of the 2D and 3D structures were observed starting from R/p ≥ 1 of the particle diameter R to the cholesteric pitch p ratio in the chiral nematic matrix . In addition to this, we have shown entangled periodic 2D and 3D chiral nematic colloidal structures using AC electric fields . The external field was used to force the colloids into the layered structures towards periodic arrangement of 2D and 3D structures without voids. Furthermore, we observed colloids in 3D, packing differently for odd and even number of layers shown in Fig.1. We also confirmed that these struct ures are not bound by van der Waals attraction by heating the sample into the isotropic phase.