Glycerol based polyether-nanogels with tunable properties via acid-catalyzed epoxide-opening in miniemulsion

A series of defined nanogels of 20-120 nm in diameter were synthesized by acid-catalyzed epoxid-opening polymerization based on glycerol in miniemulsion. Multifunctional alcohols were used as monomers and di- and triepoxides as crosslinking agents. The properties of these nanogels, i.e., size, degree of branching, viscosity, and swelling behavior, can be controlled by varying the functionalities of the monomers and crosslinkers. Inverse gated 13C NMR indicated that the addition of monomer occurred at both ends of the opened epoxide ring of the crosslinkers. This feature led to higher degree of branching and consequently to a lower viscosity of the resulting nanogels. The formation of some cycles as a possible side reaction was evidenced by different particle sizes in dry (TEM) and swollen states (DLS in water).