Synthesis of microspheres with microphase-separated shells

Novel structural microspheres of the Janus type, with microphase-separated polystyrene (PS) and poly(tert-butyl methacrylate) (PBMA) shells and crossl inked poly(2-vinyl pyridine) (PVP) cores, were synthesized with the crossli nking of PVP spherical domains in poly(styrene-block-2-vinyl pyridine-block -tert-butyl methacrylate) ABC triblock terpolymer film with PS/PBMA lamella e-PVP spherical structures. For the formation of lamellae-sphere structures , toluene, which was a selective solvent for the ABC triblock terpolymer, w as used. With the crosslinking of PVP spheres in the microphase-separated f ilm with 1,4-diiodobutane gas, the microphase structure of the terpolymer w as fixed, and microspheres composed of microphase-separated PS and PBMA she lls and P2VP cores were obtained. The size distribution of the purified mic rospheres was narrow. The characteristics of the microspheres and their agg regation behaviors in selective solvents were investigated by transmission electron microscopy and light scattering methods. (C) 2000 John Wiley & Son s, Inc.