Unidirectional alignment of surface-modified ZnO nanorods in nematic liquid crystals

Abstract

Inorganic materials such as nanotubes and nanorods have attracted much attention due to their anisotropic properties. Although controlling the alignment of inorganic materials is able to enhance their functionality, macroscopic alignment over a large area remains a challenge. We have recently proposed a simple method for inducing unidirectional alignment of ZnO nanorods on a rubbed polyimide layer. In this method, ZnO nanorods grafted with liquid-crystalline (LC) polymers are aligned by cooperative interaction between the LC moieties in the grafted polymers and surrounding LC host molecules. In this study, we investigated the unidirectional alignment of surface-modified ZnO nanorods in nematic LCs in a micrometer-thick cells. Alignment of LC polymer-grafted ZnO nanorods along nematic LC host molecules has been revealed by polarized optical micrography and ultraviolet-visible absorption spectroscopy.