Interfacial self-assembly of functional bilayer templates comprising porphyrin arrays and graphene oxide

Abstract

Fabricating of solid-supported hybrid nanostructures remains a challenging problem because it is difficult to control all interfacial interactions influencing the structure and stability of these systems. The most widely used approach to solving this problem is a bottom-up assembly on the surface templates such as self-assembled monolayers (SAMs). Herein we suggest an alternative approach to tailoring solid surfaces by a formation of an interlayer anchoring the nanostructured film to the solid substrate. We formed a multifunctional bilayer template (MBT), comprising an adhesive monolayer of graphene oxide and a functional ordered monolayer of metal organic compound (Zinc-tetra(4-pyridyl)porphyrin) directing further bottom-up growth of the nanostructures. The one-step assembly of MBT proceeded spontaneously at the air/water interface and was monitored by an in-situ fiber optic absorption and fluorescence spectroscopy in a Langmuir trough. Dilatation surface rheology was applied to study the evolution of molecular organization of the monolayers upon adding the zinc ions, GO and their mixture into the subphase. The MBT templates were used for the assembly of porphyrin-based SURMOFs with two different structures. Our strategy makes it possible to assemble surface-anchored nanostructures avoiding the use of SAMs and it can be extended to other types of ultrathin hybrid systems.