Abstract
The supramolecular structure of semi-rigid conjugated polymers can have dramatic impact on their electro-optical properties. Extensive efforts have dedicated to control the self-assembled structure and hence the luminescent behavior of conjugated polymers using, for instance, molecular design, introduction of block copolymer structure and blending. Here we present a simple approach for constructing special supramolecular structure and luminescent behavior by blending a conjugated electroluminescent polymer with a low molecular-weight amiphiphile. The systems studied are the blend of poly(2-phenyl-3-phenyl-4-(3’,7’-dimethyl octyloxy) -1,4-phenylene vinylene) (DPO-PPV) with 4-n-dodecylresorcinol (DR). The hydroxyl group in DR is able to form hydrogen bond with the ether linkage in the conjugated polymers while the hydrophobic interactions between the tails of the amiphiphiles and the polymer side chains drive. For DPO-PPV/DR blends, SAXS results show the formations of lamellar structure at the composition of x = 0.2 to 0.5 (x = molar ratio of the amiphiphile to the monomer units of the polymers) and cylindrical bundles at x = 0.7 to 1.0 in the melt state. Each cylindrical bundle is found to contain ca. 8 polymer chains subsequent crystallization of DR induced coalescence and alignment of the cylindrical bundles, yielding large-scale oriented nanowires. The chain-chain contact emission and/or aggregate emission of DPO-PPV can be reduced by increasing DR in content.