Organocatalytic Copolymerization of a Cyclic Carbonate Bearing Protected 2,2-bis(hydroxymethyl) Groups and d,l-lactide. Effect of Hydrophobic Block Chemistry on Nanoparticle Properties

The organocatalytic copolymerization of a derivative of trimethylene carbonate bearing protected 1,3-diols and d,l-lactide was studied. Homopolymerization of the cyclic carbonate from a PEG macroinitiator exhibited a controlled character, obeying pseudo first-order kinetics up to a conversion of ∼60%. Longer reactions resulted in more polydisperse materials. Kinetics of copolymerization with DLLA showed a considerable accelerative effect of the ester on the polymerizability of the carbonate, attributed to relief of steric limitations that characterize the polymerization of this and other bulky cyclic carbonates. Postpolymerization hydrogenolysis, conveniently adjusted though catalyst concentration, yielded functional poly(ester carbonate)s (PECs) with enhanced chain mobility and hydrophilicity compared to protected analogues. PEG-b-PECs were further used as stabilizers for the formation of fluorophore nanoparticles via flash nanoprecipitation. Nanoparticle size and core properties were discussed in terms ...