Preparation of graft copolymers of the AB(2) type and their equilibrium structures in bulk

Graft copolymers of the AB(2) type were prepared with various compositions, in which A graft chains are branched at the center of B chains. Their equi librium microphase-separated structures in bulk have been examined. Polysty rene (S) and poly (2-vinylpyridine) (P) are chosen as A and B components. S o, the copolymers used in this study are named SP2. The phase diagram of SP 2 graft copolymers is quite asymmetric and considerably different from that of SP diblock copolymers, reflecting the asymmetric nature of SP2 molecule s. Lamellar microdomain sparing of SP2 is quantitatively smaller than that of diblock copolymers. Furthermore, the single chain dimension of a polysty rene graft has been measured. A graft chain is less deformed than a block c hain with the same molecular weight in lamellar phase.