CORE-SHELL TYPE POLYMER MICROSPHERES PREPARED FROM BLOCK COPOLYMERS

Block copolymers with incompatible sequences exhibit characteristic morphological behavior and interesting properties, owing to microdomain formation in the solid state. By increasing the polybutadiene (PBu) content of poly(styrene (S)-butadiene (Bu)) di- or triblock copolymer, it can be observed: (1) Up to 16 PERCENT in volume; a cubic structure of PBu spheres, which is of a cubic centered type, for a PBu content between 10-16 PERCENT and (2) Between 16-18 PERCENT; an orthorhombic structure formed by short rods of PBu in a polystyrene (PS) matrix. In this article, we carried out the crosslinking reaction of poly(S-b-4VP)diblock copolymer films with poly(4-vinylpyridine) (P4VP) sphere or short rod structures with the vapor of 1,4-dibromobutane (DBB) in the solid state to obtain the core-shell type polymer microspheres. The morphology and solubility of these polymer microspheres were studied from a view-point of stabilization by crosslinking of the segregated P4VP chains in core. 18 Refs.