UC San Diego

The hybridization of crystalline, porous metal-organic frameworks (MOFs) with synthetic polymers has led to the development of unique composite materials that surpass the properties of the individual MOF and polymer components. To achieve molecular-level integration between these disparate materials, synthetic polymers containing organic linkers have been combined with inorganic building blocks for the preparation of a novel class of MOF-polymer composites, termed polyMOFs. These so-called polyMOFs merge the backbone of polymers with the lattice of the MOF to yield new materials with interesting characteristics. To promote the development of polyMOFs, the molecular arrangement of the polymers and the lattice constraints of the MOF must both be satisfied. This dissertation describes how the compatibility between MOF-architecture and polymer architecture dictate the ability to synthesize polyMOFs, and describes the emergent properties of these novel MOF-polymer materials.

Chapter 2 describes the preparation of a Zr-polyMOF (UiO-66) using 1-dimensional, amorphous polymers of various alkyl-spacers, molecular weights, and dispersities. Under the appropriate conditions, a Zr-polyMOF with a unique, interlaced morphology, and hierarchical porosity was achieved.

The concept of isoreticular (same-net) chemistry is applied to polyMOFs in Chapter 3. Linear polymers with laterally extended organic linkers afford isoreticular polyMOFs with larger pores and surface areas than described in previous works. Furthermore, it was determined that changing the position of polymer backbone connectors prevents the formation of Zr-polyMOFs, signifying the importance of polymer architecture for polyMOF formation.

In Chapter 4, block copolymers containing MOF-forming linkers and morphology directing blocks were used to synthesize block co-polyMOFs (BCPMOFs) with controlled morphologies. The morphology of Zr-BCPMOFs could be manipulated by changing the weight fraction, connectivity, and the composition of the block co-polymer ligands. Moreover, the strategy of using block copolymers to direct morphology could be applied to Zn-polyMOFs, yielding materials with narrow sizes and uniform cubic shapes.

Chapter 5 describes preliminary results for the preparation of multivariate (MTV) polyMOFs. Random copolymers containing two linkers of different axials length were used to synthesize MTV polyMOFs. Preparation of novel MTV-polyMOFs may have the potential to yield materials with controlled hierarchical porosity.