LOCALIZATION OF A HOMOPOLYMER DISSOLVED IN A LAMELLAR STRUCTURE OF A BLOCK-COPOLYMER STUDIED BY SMALL-ANGLE NEUTRON-SCATTERING

The localization of deuterated styrene homopolymer dissolved in a lame llar structure of a styrene-2-vinylpyridine diblock copolymer was stud ied in comparison with that of the end part of the block copolymer by observing diffraction from the styrene and 2-vinylpyridine microdomain s of deuterated styrene homopolymer/styrene-2-vinylpyridine diblock co polymer blends by small-angle neutron scattering (SANS). Even when the average scattering lengths of both domains were equal, that is, ''pha se contrast matching'' was theoretically achieved, diffraction was def initely observed. From the diffraction profiles in SANS and the depend ence of domain spacing on the volume fraction of the styrene homopolym er, it was found that the homopolymers are isolated in the middle of t he polystyrene domain, though they are concentrated less than the end parts of the block chains.