Abstract
The synthesis and molecular characterization of series of conformationally asymmetric polystyrene-blockpoly(1,3-cyclohexadiene) (PS-b-PCHD) diblock copolymers (PCHD: 90% 1,4 and similar to 10% 1,2), by sequential anionic copolymerization high vacuum techniques, is reported. A vvide range of volume fractions (0.27 <= (phi PS) <= 0.91) was studied by transmission electron microscopy and small-angle X-ray scattering in order to explore in detail the microphase separation behavior of these flexiblefsemiflexible diblock copolymers. Unusual morphologies, consisting of PCHD core(PCHD-1,4)-shell(PCHD-1,2) cylinders in PS matrix and three-phase (PS, PCHD-1,4, PCHD-1,2) four-layer lamellae, were observed suggesting that the chain stiffness of the PCHD block and the strong dependence of the interaction parameter chi on the PCHD microstructures are important factors for the formation of this unusual microphase separation behavior irk PS-b-PCHD diblock copolymers (C) 2016 Wile Periodicals Inc.