Synthesis of Amphiphilic Statistical Copolymers Bearing Methoxyethyl and Phosphorylcholine Groups and Their Self-Association Behavior in Water

Biocompatible amphiphilic statistical copolymers P(MEA/MPC(m)) composed of 2-methoxyethyl acrylate (MEA) and 2-methacryloyloxyethyl phosphorylcholine (MPC) were prepared with three different mol% of the hydrophilic unit MPC (m = 6, 12 and 46 mol%). The monomer reactivity ratios of MEA (r(MEA)) and MPC (r(MPC)) were 0.53 and 2.21, respectively. The r(MEA) × r(MPC) value of 1.17 demonstrated that statistical copolymerization was successful. P(MEA/MPC(12)) and P(MEA/MPC(46)) copolymers did not undergo aggregation in water, whereas the P(MEA/MPC(6)) copolymer formed micelles in water with a hydrodynamic radius (R(h)) of 96.9 nm and a critical aggregation concentration, which was determined using pyrene fluorescence, at 0.0082 g/L. The restricted motion of the protons in the hydrophobic MEA units in the micelles’ cores provided additional evidence of self-association in P(MEA/MPC(6)).