Nanophase Separation and Photochemical Reaction of Rodcoil Molecules, Liquid Crystal Molecules and Binary Mixtures

摘要

This work presents the synthesis and characterization of three related organic systems designed for self-assembly into ordered materials such as two dimensional objects and nanostructures. A family of reactive block molecules referred to as rodcoils' was synthesized for the purpose of forming nanostructures. In these reactive rodcoil molecules rod-like segments are covalently attached to less rigid coil-like segments. These rodcoil molecules were found to assemble into extremely small aggregates of dimensions on the order of 2-3 nm. New reactive thermotropic liquid crystalline compounds with structure similar to the rod segments of the rodcoil molecules were synthesized and their mesophase behavior characterized. These compounds contained photochemically sensitized groups such as anthracene and diacetylene segments. Irradiation of these materials at various temperatures led to the formation of distinct dimesogens and other high molecular weight material which allowed one of the reactive liquid crystals to act as a negative photoresist for the lithographic formation of 3- 5 micrometers features on a silicon wafer. A new methodology for the formation of nanostructures that is presented for the first time in this work is the use of binary mixtures of rodcoil molecules and chemically similar rod molecules.