Development and applications of micro-nano 3D lithography using sublimable liquid crystal

Abstract

A liquid crystal(LC) material is an intermediate phase between a solid and a liquid phase. The LCs have some degree of alignment such as a solid and has fluidity as a liquid. The optical and electromagnetic anisotropy of this LC material has been used as a major electronic material in the LC display (LCD) industry since it has very sensitive to the external field. Another noteworthy characteristic based on the anisotropy of such LC material is that it has elasticity maintaining a relatively long-range order in a certain direction. This enables a wide variety of patterns to be implemented in a wide range from a few micrometers to a few tens of nanometers in a large area, quickly and flexibly adapting not only to electromagnetic but also physicochemical environments. Furthermore, by appropriately adjusting the molecular shape, surface, and confinement effect environment, it is very advantageous to realize various patterns in a wide area ranging from a few hundreds to a few tens of nanometers as well as a few micrometers in a large area. Recently, fluorinated smectic LC molecules (SmLCs) showing sublimation on the liquid crystal, that is, the transition from the liquid crystal to the gas phase, are sublimated during the heat treatment and they are recombined at the same time, they are transferred to the layered structure having different shapes and sizes. In this Ph. D. thesis, we have developed combination lithographic technique of bottom-up and top-down using sublimation and recombination phenomenon of liquid crystal and proposed various applications. In stepwise for the studies, the sublimation property at the molecular level has been studied by synthesis and the self-assembly layered SmLC structure of the micro-nano in a variety of heat-treated environments are analyzed. Based on those investigations, many applications such as the functional nanoparticle assembly, Superhydrophobic coating method, omniphobic coating method, and nano grove template making have been demonstrated.