A novel approach is employed to produce core corona nanospheres, which introduces a stereoregular hydrophilic part to an amphiphilic block copolymer. The resultant morphology is reported using isotactic-poly(methacrylic acid)-block-poly(butyl acrylate). Infrared spectroscopy revealed a supramolecular interaction, and X ray diffraction revealed the crystallization of the outer isotactic-poly(methacrylic acid) part. The nanostructure, which looks like a nanosized 'grape', was formed when nanospheres and nanofibers coexisted simultaneously and partially fused.