Orientation and defects on a surface of a thin film of a self-assembled supramolecular dendrimer

Abstract

We have investigated the orientation and morphology of a taper shaped supramolecular dendrimer by high resolution transmission electron microscopy (HRTEM). The molecule exhibits hexagonal cylindrical mesophase upon cooling from isotropic melt. Orientation of the cylinders is strongly influenced by surface treatment. Homeotropic alignment of the molecule occurs on carbon substrates, while homogeneous orientation is favored on water substrate. This is an easy way to control orientation of the cylinders, compared to that of block copolymers, leading to a promising material for the nano-sized surface patterning. A variety of defects, which include grain boundaries, elementary edge dislocation and disclinations, have been observed, representing flexible stacking of the molecules.