MICROPHASE-SEPARATED INTERFACE OF A 2-COMPONENT TRIBLOCK COPOLYMER WITH A LAMELLAR STRUCTURE

Conformations of middle block chains of 2-vinylpyridine-styrene-2-viny lpyridine (PSP) triblock copolymers with lamellar microphase-separated structures were investigated by small-angle neutron scattering. The r adii of gyration of the middle block chains were evaluated in two dire ctions parallel and perpendicular to the lamellar interface. It was fo und that the middle block chains were elongated along the direction no rmal to lamellar interface irrespective of the volume fraction of the S-block chain, phi(S), but also found that the degree of deformation w as decreasing with increasing phi(S). Further, lamellar interfacial st ructure of a PSP triblock copolymer with phi(S) of 0.50 was investigat ed by measuring specular neutron reflection. The interfacial profile w as well described by an error function with its full-width at half-max imum 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.