Synthesis of the Metal-Organic Framework UiO-66 in the Form of Nanoparticles with a Modified Surface

We report on a synthesis procedure for obtaining a UiO-66 metal-organic framework in the form of nanoparticles with a modified surface. A distinctive feature of the developed procedure is that modification occurs directly during synthesis. Biocompatible polyethylene glycol (PEG) is selected as the organic polymer covering the surface of the UiO-66 nanoparticles. The effect of the degree of PEG polymerization on the size, morphology, and surface charge of UiO-66 nanoparticles is studied. The presence of PEG molecules is confirmed by infrared (IR) spectroscopy. The materials obtained are single phase and characterized by a high degree of crystallinity. The particle size varies from 80 to 120 nm, depending on the type of PEG used. A high surface charge in an aqueous medium (ζ-potential over 20 mV) indicates the possibility of forming a stable suspension. Thus, the obtained materials are promising as nanocontainers for the delivery of biologically active substances.