Concentration‐dependent Seeding as a Strategy for Fabrication of Densely Packed SURMOF Layers

The layer-by-layer (LbL) method is a well-established method for the growth of surface-attached metal-organic frameworks (SURMOFs). Various experimental parameters, like surface functionalization or temperature, have been identified as essential in the past. In this study, inspired by these recent insights regarding the LbL SURMOF growth mechanism, we investigated the impact of reactant solutions concentration on LbL growth of the Cu2(F4bdc)2 (dabco) SURMOF (F4bdc2- = tetrafluorobenzene-1,4-dicarboxylate and dabco = 1,4-diazabicyclo-[2.2.2]octane) in situ using quartz-crystal microbalance and ex situ with a combination of spectroscopic, diffraction and microscopy techniques. It was found that number, size and morphology of MOF crystallites are strongly influenced by the reagent concentration. By adjusting the interplay of nucleation and growth, we were able to produce densely packed, yet thin films, which are highly desired for a variety of SURMOF applications.