Highly ordered hierarchical poly(ethylene oxide)-b-polystyrene/organoclay nanocomposites.

A lamellar forming poly(ethylene oxide)-b-polystyrene (PEO-b-PS)/organoclay nanocomposite with a unique hierarchical structure has been fabricated, by casting solution blends of the block copolymer and organoclay, with subsequent annealing at 180 °C for 8 h under uniaxial constraint. PEO-b-PS provided the nanocomposite lamellar structure with a slightly increased long period. Lamellar layers of the nanocomposite block copolymer were oriented parallel to the film plane. Fully exfoliated clay platelets were localized mostly in the aligned PEO layers, and all platelets were found to be parallel to the interface between PEO and PS layers. PEO crystals in the nanocomposite were oriented with the c-axis perpendicular to the phase-separated layers. The orientation function degree of the PEO crystals within the nanocomposite was lower than that of the crystals within the neat block copolymer.