Nano-disks prepared by using the phase separation structures in block copolymer nanoparticles

It is known that block copolymers are formed micro-phase separation structures in their thin films. We have reported that the block copolymer nano-particles with micro-phase separation structures can be prepared by evaporation of THF from the THF/water mixing solution of the block copolymer. In this study, we prepared the nanosized disk structures from the block copolymer nanoparticles. After selective cross-linking of isoprene double bonds with OsO₄, the solvent was exchanged from water to THF, which is a good solvent of polystyrene. Moreover, the solution was sonicated. As a result, the nano-disk structures were formed. The detail structure of the nano-disks were observed by scanning transmission electron microscopy (STEM).