Metal organic frameworks at interfaces

Abstract

Metal organic frameworks (MOFs) consist of metal ions or clusters connected by organic ligands in a crystalline infinite coordination network. MOFs have been studied for many different applications over the past decade due to their unique properties such as high surface area, pore size and designable framework. Beside the extensive research on MOF powders, many efforts have been also focused on obtaining homogenous and defect-free MOF (thin) films that can be used in separation, catalysis, electronic, photonic and sensor applications. In this thesis, the overall objective is to develop new insights to understand the role of the interface for MOF film preparation and properties. For this, firstly, thin films of benchmark MOFs, Cu-BTC and ZIF-8 are prepared on two novel functional supports (metal: porous copper hollow fiber and polymer: ion exchange membranes). The control over the concentrations of the reactants at the interface of the substrate are found very crucial. Secondly, the effect of the post-thermal treatment on interfacial properties and gas separation performance is investigated for MOF embedded polymer films. As a result of the post-thermal treatment approach to improve the separation performance, amorphization and oxidation of MOFs should be further investigated to understand the MOF/polymer interface as well as the gas separation performance. Thirdly, we have looked at the interfacial properties of MOF films from the surface characteristic and adhesion properties point of view. Their potential in various applications can be further explored by using the work of this thesis. MOF film preparation and understanding their interfacial properties can inspire future research on use of functional substrates, designing better MOF/polymer or MOF/substrate interfaces to improve the adhesion and compatibility. It is hoped the work of this thesis along with all these positive and negative results can be expected to aid further development and application of thin MOF films.