Swelling and Shrinkage of Lamellar Domain of Conformationally Restricted Block Copolymers by Metal Chloride*

The lamellar domain spacing (D) of symmetric polystyrene-block- poly(2-vinyl pyridine) copolymer (PS-P2VP) and PS-block-poly(4- vinyl pyridine) copolymer (PS-P4VP) with cadmium chloride (CdCl2) were studied by using rheometry, small angle X-ray scattering and transmission electron microscopy. With increasing amount of CdCl2, D of PS-P2VP increased greatly, but it decreased for PS-P4VP. This is due to different types of the coordination between CdCl2 and nitrogen atoms in the 2-position of pyridine ring (intra-chain coordination), compared with nitrogen atoms in the 4-position (inter-chain coordination).