Microphase-separated interface of a two-component triblock copolymer with a lamellar structure

Conformations of middle block chains of 2-vinylpyridine-styrene-2-vinylpyridine (PSP) triblock copolymers with lamellar microphase-separated structures were investigated by small-angle neutron scattering. The radii of gyration of the middle block chains were evaluated in two directions parallel and perpendicular to the lamellar interface. It was found that the middle block chains were elongated along the direction normal to lamellar interface irrespective of the volume fraction of the S-block chain, phi(S), but also found that the degree of deformation was decreasing with increasing phi(S). Further, lamellar interfacial structure of a PSP triblock copolymer with phi(S) of 0.50 was investigated by measuring specular neutron reflection. The interfacial profile was well described by an error function with its full-width at half-maximum value of 4.0 nm, which is fairly close to the value obtained for styrene-2-vinylpyridine diblock copolymers. (C) 1998 Elsevier Science B.V. All rights reserved.