Growth and orientation of copper gallate SURMOFs on cellulosic thin films

Anisotropic surface-mounted metal organic frameworks (SURMOFs) are interesting for electronic, photonic, and sensing applications. Oriented copper gallate films could be obtained by the continuous flow layer-by-layer (LbL) approach from ethanolic solutions. The layer formation of SURMOFs was investigated by quartz crystal microbalance with dissipation monitoring (QCM-D) in real time and crystal orientation was determined by grazing incidence wide angle X-ray scattering (GIWAXS). A deposition of 500 ng cm^-2 per individual layer was found. For SURMOFs grown on SiO₂ and cellulose surfaces, the diffraction plane along the pillars of copper octahedra was found to be predominantly oriented parallel to the surface. Cellulosic films possessing catecholic moieties led to complexation of copper ions on randomly oriented polymer chains resulting in SURMOFs without orientation. Thus, the orientation of copper gallate SURMOFs could be controlled by functional cellulosic thin films.