Copolymers with tailored microstructure as versatile platforms for ZIF-8 polyMOF growth

Abstract

In this work, we report copolymers based on zinc dimethacrylate (ZnDMA) and poly(ethylene glycol)methyl ether methacrylate (PEGMA) as versatile platforms for the in situ growth of ZIF-8 polyMOFs. ZnDMA is a suitable monomer which can potentially optimize polyMOF growth, enabling improved control over the nucleation process and both final structure and morphology. The copolymers were synthesized both as bulk materials from precursor solutions and via surface-initiated Atom Transfer Radical Polymerization (ATRP). The composition and microstructure were investigated using the Fineman-Ross method, complemented by characterization through X-ray photoelectron spectroscopy (XPS), proton nuclear magnetic resonance (¹H NMR), thermogravimetric analysis (TGA), aqueous size exclusion chromatography (SEC) and scanning electron microscopy (SEM). We found that variations in structural stability, composition and microstructure of the resulting poly(ZnDMA-co-PEGMA)@ZIF-8 materials can be traced back to conditions affecting polyMOF growth, mainly regarding efficient nucleation and controlled crystalline growth. Overall, these results demonstrate that the hereby proposed synthetic approach to polyMOFs can be employed for the rational design of functional nanostructured porous materials.