Self-assembly of inorganic nanorods: a block copolymer paradigm

Z. Nie, D. Fava, S. Zou, G.C. Walker, M. Rubinstein, E. Kumacheva
University of Toronto, CA

Keywords: metal nanorods, polymers, photolithography, self-assembly, electronic properties, optical properties

Abstract:

Organized arrays of anisotropic nanoparticles show electronic and optical properties that originate from the coupling of shape-dependent properties of the individual nanorods. The organization of nanorods in a controllable and predictable way provides a route to the fabrication of new materials and functional devices. So far, significant progress has been achieved in the self-assembly of nanorod arrays, yet the realization of a range of different structures requires changing the surface chemistry of the nanoparticles.We assembled metal nanorods in structures with varying geometries by using a striking analogy between amphiphilic ABA triblock copolymers and the hydrophilic nanorods tethered with hydrophobic polymer chains at both ends. The self-assembly was tunable and reversible and it was achieved solely by changing the solvent quality for the constituent blocks. We mapped a the structures of the nanorods on the phase-like diagrams and demonstrated control over the optical properties of the self-assembled structures. This approach provides a new route to the organization of anisotropic nanoparticles by using the strategies that are established for the self-assembly of block copolymers.