Hierarchical nanostructures of bent-core molecules blended with poly(styrene-b-4-vinylpyridine) block copolymer

We report the phase structures observed in blends of poly(styrene-b-4- vinylpyridine) (PS-b-P4VP) block copolymer (BCP) and a bent-core molecule 1-[4′-(3″,4″,5″-tridecyloxybenzoyloxy) phenyleneoxycarbonyl]-3-[(4′-hydroxyphenyl)oxycarbonyl]benzene (BP). Hydrogen bonding between the terminal -OH group of BP and pyridine of P4VP led to the formation of P4VP(BP) _n complex, which exhibited liquid crystalline (LC) order. This LC ordering, combined with microphase separation of the BCP, led to the formation of hierarchical nanostructures. The phase structures of the blend samples were investigated as a function of the concentration of BP using small-angle and wide-angle X-ray scattering and transmission electron microscopy techniques. By increasing the BP content, BCP phase morphology transformed from lamellae to cylinders. In the two cases investigated, the P4VP/BP complex formed a bilayer smectic A LC structure within the BCP domains, and these layered structures were oriented perpendicular to the BCP interface, A detailed structural and morphological study will be reported.