Self-assemblies of block copolymer of 2-perfluorooctylethyl methacrylate and methyl methacrylate

Self-assemblies of poly(methyl methacrylate)-block-poly(2-perfluorooctylethyl methacrylate)-block copolymers in organic solvents were examined. It was confirmed from light scattering that block copolymers formed aggregates of 410 molecules in acetonitrile and of 26 molecules in chloroform. Spherical morphologies were displayed in cryo-transmission electron-microscope (cryo-TEM) photographs and in atomic-force microscope images. The spherical particles consisted of a core of poly(2-perfluorooctylethyl methacrylate) and a shell (corona) of poly(methyl methacrylate). It was elucidated from molecular geometry that the particles in acetonitrile are typical polymer micelles of ∼150 Å core radius and ∼150 Å corona thickness, while those in chloroform are ‘crew-cut’ aggregates. The external contrast variation examination of small-angle neutron scattering and cryo-TEM suggested that the solvent penetration into polymer micelles in acetonitrile is less in the core than in the shell.