Hydrogen-Bonded Siloxane Liquid Crystals for Hybrid Nanomaterials

Abstract

The self-assembly of molecular inorganic/organic hybrid building blocks into ordered hierarchical nanomaterials with a tunable morphology is an enormous challenge. Here, we describe the synthesis and characterization of a novel liquid crystalline hydrogen-bonding hepta(dimethylsiloxane) azobenzene carboxylic acid dimer. This inorganic/organic hybrid dimer forms sub-5 nm lamellar features in the bulk and at the liquid solid interface. When mixed with a complementary hydrogen-bonding disk-shaped small molecule, a columnar hexagonal phase is formed. When adding a block copolymer containing hydrogen bond-accepting moieties, a hierarchical nanostructured material is obtained with a hexagonal columnar arrangement perpendicular to lamellae super structure. Our supramolecular approach shows that hierarchical hybrid nanomaterials can be fabricated with controlled properties which is appealing for applications such as nanoporous materials, organic electronics, and nanolithography.