Core‐shell type polymer microspheres prepared by domain fixing of block copolymer films

Well‐defined poly[styrene(S)‐b‐isoprene(I)] diblock copolymers were prepared by sequential anionic addition. The crosslinking reactions of polyisoprene (PI) spherical domains of these block copolymers were carried out in a n ‐hexane solution of sulfur monochloride (S 2 Cl 2 ). Electron micrograph of crosslinked products indicates the structure of core‐shell type polymer microspheres. It is found from NMR and turbi+imetric measurements that the solubility of core‐shell type polymer microspheres depends strongly on that of block chains comprising the shell portion. The particle size of these microspheres shows a narrow distribution.