Direct Nanorod Assembly Using Block Copolymer-Based Supramolecules

One-dimensional nanomaterials with high aspect ratios, such as nanorods, exhibit unique and useful anisotropic optical, magnetic, and electrical properties. The collective properties of 1-D nanomaterials depend on their spatial arrangements, interparticle ordering, and macroscopic alignment. Developing routes to control their organization with high precision is critical to generate functional materials. We have investigated the co-assemblies of nanorods and block copolymer (BCP)-based supramolecules that self-assemble into spherical, lamellar and cylindrical morphologies. By varying energetic contributions from the rod-rod interactions and the deformation of the supramolecule, a wide library of nanorod assemblies including highly aligned arrays, continuous networks, and clusters can be readily accessed. Since macroscopic alignment of BCP microdomains can be obtained by application of external fields, present studies open up a new route to manipulate macroscopic alignments of nanorods. Fundamentally, these studies have demonstrated that in these blends, the energetic contributions from the polymer chain deformation and rod-rod interactions are comparable and can be tailored to disperse nanorods with control over inter-rod ordering and their relative alignment.