Synthesis of Biomimetic Poly(2-(methacryloyloxy)ethyl phosphorylcholine) Nanolatexes via Atom Transfer Radical Dispersion Polymerization in Alcohol/Water Mixtures

Poly(2-(methacryloyloxy)ethyl phosphorylcholine) (PMPC) exhibits a phenomenon known as co-nonsolvency in certain alcohol/water binary mixtures. We have exploited this phenomenon to prepare a series of sterically stabilized PMPC nanolatexes by atom transfer radical polymerization (ATRP) under dispersion polymerization conditions using a near-monodisperse poly(ethylene oxide) (PEO) macroinitiator in a 9:1 isopropanol/water mixture. The as-synthesized nanolatex particles comprised nonsolvated PMPC cores and solvated PEO shells, as determined by 1H NMR spectroscopy. In our preliminary experiments linear core-forming PMPC chains were targeted, but alternatively either ethylene glycol dimethacrylate or bisphenol A dimethacrylate can be used as comonomers (at up to 10 mol % based on MPC) in order to prepare cross-linked PMPC particles that acquire swollen microgel character when dialyzed against pure water. Low levels of cross-linker (e.g., 4 mol %) lead to bimodal microgel size distributions as judged by dynami...