Synthesis of amphiphilic copolymers by soap-free interface-mediated polymerization

Abstract

Amphiphilic copolymers were synthesized by soap-free heterogeneous polymerization and a novel method of polymer composition control for heterogeneous polymerization is proposed. Various copolymers of 2-methacryloyloxyethylphos-phorylcholine (MPC) and alkyl methacrylates, such as n-hexyl methacrylate (HMA), n-dodecyl methacrylate (DMA), and stearyl methacrylate (SMA), were synthesized by soap-free heterogeneous polymerization. The reaction was carried out with the same monomer concentration but at different solvent compositions. This strategy could control the polymer composition despite the same monomer ratio. The behaviors of polymer composition were different depending on alkyl methacrylate species. It appears that a change of solvent polarity causes a change of the interface between the solution phase and the alkyl methacrylate phase. This phenomenon could be accounted on two factors. First, an increase in the solvent polarity results in an increase of the methacryloyl moieties which orient to the interface to solution phase because methacryloyl moieties are relatively more polar than alkyl chains. Second, the tendency of alkyl methacrylate phase to disperse in the solution phase decreases as the solvent polarity increases. © 2009 The Society of Polymer Science.