Hydration of Hydrophobic Iron–Carbonyl Homopolymers via Water–Carbonyl Interaction (WCI): Creation of Uniform Organometallic Aqueous Vesicles with Exceptionally High Encapsulation Capacity

Abstract

Metal–carbonyl homopolymers (PFpPs) are hydrophobic but able to self-assemble in water into uniform and stable colloids. Hydrodynamic radius (Rh) of the colloids varies from 42 to 77 nm depending on preparation conditions. Light scattering, TEM, and AFM analyses of the colloids indicate that the colloids have a vesicular morphology with membrane thickness of ca. 3.0–4.0 nm. This thin membrane is, however, relatively rigid compared to conventional polymersomes. FT-IR and NMR analyses indicate that water–carbonyl interactions (WCI) is a motif responsible for the self-assembly and colloidal stability. By using nanoprecipitation encapsulation technique, PFpP vesicles can enclose hydrophilic molecules with extremely high encapsulation efficiency (EE) and loading capacity (LC). This work opens up a new research topic on hydration driven self-assembly and resolves a long-standing challenge of low EE and LC for the encapsulation of hydrophilic molecule via nanoprecipitation using amphiphilic molecules.