Internal morphologies of diblock copolymer nanorods fabricated from regular and irregular pores of anodized aluminum oxide templates

Internal nanostructures in nanorods of polystyrene-poly(4-vinyl pyridine) (PS-PVP) diblock copolymers fabricated from pores having regular or irregular contours in AAO templates were investigated by cross-sectional transmission electron microscopy. When nanorods of PS-PVP copolymers were produced from pores with regular contours, a typical morphology of concentric cylinders was observed due to the strong affinity of the PVP block to the surface of the AAO pores. In the case of PS-PVP nanorods obtained from pores with irregular contours, a concentric cylindrical morphology was not induced. Instead, a nanostructure of lamellae mostly parallel to the axis of the nanorods was observed with a similar period of lamellae to the bulk lamellar period. In addition, nanorods having a functional coaxial nanostructure were fabricated by synthesizing Au nanoparticles in concentric cylinders of the nanorods to demonstrate the utilization of self-assembled internal nanostructures in nanorods.